Ant Nebula ( Menzel 3, Mz 3 )
Menzel 3 is a young bipolar planetary nebula (PN) in the constellation Norma that is composed of a bright core and four distinct high-velocity outflows that have been named lobes, columns, rays, and chakram.
These nebulosities are described as: two spherical bipolar lobes, two outer large filamentary hour-glass shaped columns, two cone shaped rays, and a planar radially expanding, elliptically shaped chakram. Mz 3 is a complex system composed of three nested pairs of bipolar lobes and an equatorial ellipse.
Horsehead Nebula is a small dark nebula in the constellation Orion. The nebula is located just to the south of Alnitak, the easternmost star of Orion’s Belt, and is part of the much larger Orion Molecular Cloud Complex.
It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming H II region called IC 434.
The Horsehead Nebula is approximately 422 parsecs or 1,375 light-years from Earth. It is one of the most identifiable nebulae because of its resemblance to a horse’s head.
NGC – 6334
NGC 6334, colloqually known as the Cat’s Paw Nebula, Bear Claw Nebula, or Gum 64, is an emission nebula and star-forming region located in the constellation Scorpius.
It was discovered by astronomer John Herschel in 1837, who observed it from the Cape of Good Hope in South Africa. The nebula is located in the Carina–Sagittarius Arm of the Milky Way, at a distance of approximately 5.5 kilolight-years from the Sun
The nebula is a high mass filamentary cloud structure spanning ~320 ly. Several embedded star-forming regions have been identified from infrared and radio emissions. Four of these sites have formed H II regions.
NGC – 6537
NGC 6357 is a diffuse nebula near NGC 6334 in the constellation Scorpius. The nebula contains many proto-stars shielded by dark disks of gas, and young stars wrapped in expanding “cocoons” or expanding gases surrounding these small stars.
It is also known as the Lobster Nebula and the Madokami Nebula by some fans of the anime Madoka Magica due to its resemblance to the main character from the anime and a popular fan petition to rename it.
This nebula was also given the name War and Peace Nebula by the Midcourse Space Experiment scientists because of its appearance, which, in infrared images the bright, western part resembles a dove, while the eastern part looks like a skull.
It is located about 5500 light years away from Earth.
NGC – 7023
Lady Lucas quieted her fears a little by starting the
The Iris Nebula (also known as NGC 7023 and Caldwell 4) is a bright reflection nebula in the constellation Cepheus.
The designation NGC 7023 refers to the open cluster within the larger reflection nebula designated LBN 487.
The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated SAO 19158.
It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alphirk). It lies 1,300 light-years away and is six light-years across.
V838 – Monocreotis
V838 Monocerotis is a star in the constellation Unicorn, one of the largest known stars. It was discovered on January 6, 2002 by an amateur astronomer. Today it is considered one of the most interesting variable stars.
Its exact nature is not yet clear. It is originally assumed to be new. Today, astronomers believe that its recent evolution has diverted it from the main sequence and is becoming a red supper.
Until then, however, it is assumed that this phase lasts up to thousands of years, but in the case of V 838 Monocerotis took place in a few months. It can also be a completely new kind of eruptive variable star.
The hypotheses about the cause of its variability are very different, some suggest that they are part of a binary.
C 1101 is a supergiant elliptical galaxy at the center of the Abell 2029 galaxy cluster and is one of the largest known galaxies. Its halo extends about 600 kiloparsecs (2 million light-years) from its core, and it has a mass of about 100 trillion stars. The galaxy is located 320 megaparsecs (1.04 billion light-years) from Earth.
The galaxy is classified as a supergiant elliptical (E) to lenticular (S0) and is the brightest galaxy in A2029 (hence its other designation A2029-BCG; BCG meaning brightest cluster galaxy).
The galaxy’s morphological type is debated due to it possibly being shaped like a flat disc but only visible from Earth at its broadest dimensions. However, most lenticulars have sizes ranging from 15 to 37 kpc (50 to 120 thousand ly).
The Kuiper Belt
The Kuiper belt occasionally called the Edgeworth–Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun.
It is similar to the asteroid belt, but is far larger – 20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed.
While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles (termed “ices”), such as methane, ammonia and water.
Westerhout 40 is a star-forming region in our galaxy located in the constellation Serpens Cauda. In this region, interstellar gas forming a diffuse nebula surrounds a cluster of several hundred new-born stars.
The distance to W40 is 436±9 pc (1420±30 light-years), making it one of the closest sites of formation of high-mass O- and B-type stars.
Dust from the molecular cloud in which W40 formed obscures the nebula, rendering W40 difficult to observe at visible wavelengths of light. Thus, X-ray, infrared, and radio observations have been used to see through the molecular cloud to study the star-formation processes going on within.
NGC – 6888
The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792.
It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago.
The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.
C Sharpless 2 – 106
Sh2-106 is an emission nebula and a star formation region in the constellation Cygnus. It is a H II region estimated to be around 2,000 ly (600 pc) from Earth, in an isolated area of the Milky Way.
In the center of the nebula is a young and massive star that emits jets of hot gas from its poles, forming the bipolar structure. Dust surrounding the star is also ionized by the star. The nebula spans about 2 light-years across.
RCW 34 (Gum 19) – H II region and the emission nebula located in the constellation Vela. It is located approximately 22,000 light years from Earth. Named after Australian astronomer Colin Stanley Gum.
The nebula RCW 34 is relatively dark. However, when observed using infrared wavelengths, two different areas are visible – one half of the nebula is bright, the other is dark. The bright side is the hydrogen illuminated by a nearby blue supergiant star, and dark is the place where new stars surround the central star on the other side.
The source of energy that stimulates the nebula RCW 34 to shine is a huge, extremely hot star V391 Velorum with a surface temperature of up to 30,000 °C.
NGC 3372 – The Carina Nebula
The Carina Nebula is a large, complex area of bright and dark nebulosity in the constellation Carina, and is located in the Carina–Sagittarius Arm. The nebula is approximately 8,500 light-years (2,600 pc) from Earth.
The nebula has within its boundaries the large Carina OB1 association and several related open clusters, including numerous O-type stars and several Wolf–Rayet stars. Carina OB1 encompasses the star clusters Trumpler 14 and Trumpler 16.
Trumpler 14 is one of the youngest known star clusters at half a million years old. Trumpler 16 is the home of WR 25, currently the most luminous star known in our Milky Way galaxy, together with the less luminous but more massive and famous Eta Carinae star system and the O2 supergiant HD 93129A.
The Lagoon Nebula (catalogued as Messier 8 or M8, NGC 6523, Sharpless 25, RCW 146, and Gum 72) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as an H II region.
The Lagoon Nebula is estimated to be between 4,000-6,000 light-years away from the Earth. In the sky of Earth, it spans 90′ by 40′, which translates to an actual dimension of 110 by 50 light years.
Like many nebulas, it appears pink in time-exposure color photos but is gray to the eye peering through binoculars or a telescope, human vision having poor color sensitivity at low light levels.
The Tarantula Nebula (also known as 30 Doradus) is an H II region in the Large Magellanic Cloud (LMC), from the solar system’s perspective forming its south-east corner.
The Tarantula Nebula was observed by Nicolas-Louis de Lacaille during an expedition to the Cape of Good Hope between 1751 and 1753. He catalogued it as the second of the “Nebulae of the First Class”, “Nebulosities not accompanied by any star visible in the telescope of two feet”. It was described as a diffuse nebula 20′ across.
The Tarantula Nebula has an apparent magnitude of 8. Considering its distance of about 49 kpc (160,000 light-years), this is an extremely luminous non-stellar object. Its luminosity is so great that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast visible shadows. In fact, it is the most active starburst region known in the Local Group of galaxies.
Fox Fur Nebula
Fox Fur Nebula is a nebula located in Monoceros and included in the NGC 2264 Region. In the Sharpless catalog it is number 273.
This formation of gas and dust lies in the constellation of Monoceros (the Unicorn) not far off the right arm of Orion. The image is a close-up of a small section of a much larger complex, generally known as the Christmas Tree cluster. The mysterious Cone Nebula is also a part of this same cloud.
The Eskimo Nebula (NGC 2392), also known as the Clown-faced Nebula, Lion Nebula, or Caldwell 39, is a bipolar double-shell planetary nebula (PN).
It was discovered by astronomer William Herschel in 1787.
The formation resembles a person’s head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star.
The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual, light-year-long filaments.
NGC 2392 lies about 6500 light-years away, and is visible with a small telescope in the constellation of Gemini.
The Pelican Nebula
The Pelican Nebula (also known as IC 5070 and IC 5067) is an H II region associated with the North America Nebula in the constellation Cygnus. The gaseous contortions of this emission nebula bear a resemblance to a pelican, giving rise to its name.
The Pelican Nebula is located nearby first magnitude star Deneb, and is divided from its more prominent neighbour, the North America Nebula, by a molecular cloud filled with dark dust.
The Pelican is much studied because it has a particularly active mix of star formation and evolving gas clouds.
The Helix Nebula (also known as NGC 7293 or Caldwell 63) is a planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, probably before 1824, this object is one of the closest to the Earth of all the bright planetary nebulae.
The distance, measured by the Gaia mission, is 655±13 light-years. It is similar in appearance to the Cat’s Eye Nebula and the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula, varying only in its relative proximity and the appearance from the equatorial viewing angle.
The Helix Nebula has sometimes been referred to as the “Eye of God” in pop culture, as well as the “Eye of Sauron”.
Barnard’s Loop (catalogue designation Sh 2-276) is an emission nebula in the constellation of Orion. It is part of the Orion Molecular Cloud Complex which also contains the dark Horsehead and bright Orion nebulae. The loop takes the form of a large arc centered approximately on the Orion Nebula. The stars within the Orion Nebula are believed to be responsible for ionizing the loop.
The loop extends over about 600 arcminutes as seen from Earth, covering much of Orion. It is well seen in long-exposure photographs, although observers under very dark skies may be able to see it with the naked eye.
Recent estimates place it at a distance of either 159 pc (518 light years) or 440 pc (1434 ly) giving it dimensions of either about 100 or 300 ly across respectively.
It is thought to have originated in a supernova explosion about 2 million years ago, which may have also created several known runaway stars, including AE Aurigae, Mu Columbae and 53 Arietis, which are believed to have been part of a multiple star system in which one component exploded as a supernova.
The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus.
The common name comes from William Parsons, 3rd Earl of Rosse, who observed the object in 1840 using a 36-inch telescope and produced a drawing that looked somewhat like a crab.
The nebula was discovered by English astronomer John Bevis in 1731, and it corresponds with a bright supernova recorded by Chinese astronomers in 1054.
The nebula was the first astronomical object identified that corresponds with a historical supernova explosion.
The Rosette Nebula (also known as Caldwell 49) is an H II region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy.
The open cluster NGC 2244 (Caldwell 50) is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula’s matter.
The cluster and nebula lie at a distance of 5,000 light-years from Earth) and measure roughly 130 light years in diameter.
The Ring Nebula
The Ring Nebula (also catalogued as Messier 57, M57 or NGC 6720) is a planetary nebula in the northern constellation of Lyra.
Such objects are formed when a shell of ionized gas is expelled into the surrounding interstellar medium by a star in the last stages of its evolution before becoming a white dwarf.
M57 is 0.787 kpc (2,570 light-years) from Earth. It has a visual magnitude of 8.8 and photographic magnitude of 9.7.
Photographs taken over a period of 50 years show the rate of nebula expansion is roughly 1 arcsecond per century, which corresponds to spectroscopic observations as 20–30 km s−1. M57 is illuminated by a central white dwarf or planetary nebula nucleus (PNN) of 15.75v visual magnitude.
The Cat’s Eye Nebula
The Cat’s Eye Nebula (also known as NGC 6543 and Caldwell 6) is a planetary nebula in the northern constellation of Draco, discovered by William Herschel on February 15, 1786.
It was the first planetary nebula whose spectrum was investigated by the English amateur astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature.
Structurally, the object has had high-resolution images by the Hubble Space Telescope revealing knots, jets, bubbles and complex arcs, being illuminated by the central hot planetary nebula nucleus (PNN).
It is a well-studied object that has been observed from radio to X-ray wavelengths.
The Boomerang Nebula is a protoplanetary nebula located 5,000 light-years away from Earth in the constellation Centaurus.
It is also known as the Bow Tie Nebula and catalogued as LEDA 3074547. The nebula’s temperature is measured at 1 K (−272.15 °C; −457.87 °F) making it the coolest natural place currently known in the Universe.
The Boomerang Nebula is believed to be a star system evolving toward the planetary nebula phase.
It continues to form and develop due to the outflow of gas from its core where a star in its late stage life sheds mass and emits starlight illuminating dust in the nebula.
The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611, and also known as the Star Queen Nebula and The Spire) is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Cheseaux in 1745–46.
Both the “Eagle” and the “Star Queen” refer to visual impressions of the dark silhouette near the center of the nebula, an area made famous as the “Pillars of Creation” imaged by the Hubble Space Telescope.
The nebula contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation.
The Eagle Nebula is part of a diffuse emission nebula, or H II region, which is catalogued as IC 4703. This region of active current star formation is about 5700 light-years distant.
The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features.
The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust.
The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion’s Belt in the constellation of Orion. It is one of the brightest nebulae, and is visible to the naked eye in the night sky.
M42 is located at a distance of 1,344 ± 20 light years and is the closest region of massive star formation to Earth.
The Medusa Nebula is a planetary nebula in the constellation of Gemini.
It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula. Until the early 1970s, the nebula was thought to be a supernova remnant.
With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported.
NGC 6302 (also known as the Bug Nebula, Butterfly Nebula, or Caldwell 69) is a bipolar planetary nebula in the constellation Scorpius. The structure in the nebula is among the most complex ever observed in planetary nebulae.
The spectrum of NGC 6302 shows that its central star is one of the hottest stars known, with a surface temperature in excess of 250,000 degrees Celsius, implying that the star from which it formed must have been very large.
The central star, a white dwarf, was identified in 2009, using the upgraded Wide Field Camera 3 on board the Hubble Space Telescope. The star has a current mass of around 0.64 solar masses. It is surrounded by a dense equatorial disc composed of gas and dust.
This dense disc is postulated to have caused the star’s outflows to form a bipolar structure similar to an hourglass.
Flaming Star Nebula
IC 405 (also known as the Flaming Star Nebula, SH 2-229, or Caldwell 31) is an emission and reflection nebula in the constellation Auriga, surrounding the bluish star AE Aurigae. It shines at magnitude +6.0.
It surrounds the irregular variable star AE Aurigae and is located near the emission nebula IC 410, the open clusters M38 and M36, and the K-class star Iota Aurigae.
The nebula measures approximately 37.0′ x 19.0′, and lies about 1,500 light-years away from Earth.
Westerhout – 5
Westerhout 5 (Sharpless 2-199, LBN 667, Soul Nebula) is an emission nebula located in Cassiopeia. Several small open clusters are embedded in the nebula: CR 34, 632, and 634 (in the head) and IC 1848 (in the body).
The object is more commonly called by the cluster designation IC 1848.
Small emission nebula IC 1871 is present just left of the top of the head, and small emission nebulae 670 and 669 are just below the lower back area.
The galaxies Maffei 1 and Maffei 2 are both nearby the nebula, although light extinction from the Milky Way makes them very hard to see.
Once thought to be part of the Local Group, they are now known to belong to their own group- the IC 342/Maffei Group.
This complex is the eastern neighbor of IC1805 (Heart Nebula) and the two are often mentioned together as the “Heart and Soul”.
Sh2 – 279
Sh2-279 (alternatively designated S279 or Sharpless 279) is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion.
It is the northernmost part of the asterism known as Orion’s Sword, lying 0.6° north of the Orion Nebula. The reflection nebula embedded in Sh2-279 is popularly known as the Running Man Nebula.
Sh2-279 comprises three NGC nebulae, NGC 1973, NGC 1975, and NGC 1977 that are divided by darker nebulous regions.
It also includes the open cluster NGC 1981. The brightest nebulosity, later listed as NGC 1977, was discovered by William Herschel in 1786. He catalogued it as “H V 30″ and described ” 42 Orionis and nebula”
The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion. It is about 900 to 1,500 light-years away.
The bright star Alnitak (ζ Ori), the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame and this knocks electrons away from the great clouds of hydrogen gas that reside there.
Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas.
The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.
IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248) is a galactic supernova remnant (SNR) in the constellation Gemini.
On the plane of the sky, it is located near the star Eta Geminorum. Its distance is roughly 5,000 light years from Earth. IC 443 may be the remains of a supernova that occurred 3,000 – 30,000 years ago.
IC 443 is an extended source, having an angular diameter of 50 arcmin (by comparison, the full moon is 30 arcmin across).
NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia.
It lies close to the direction of the open cluster Messier 52. The “bubble” is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575 (BD+60°2522).
The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow.
It was discovered in 1787 by William Herschel. The star BD+60°2522 is thought to have a mass of about 44 M☉.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus.
It constitutes the visible portions of the Cygnus Loop, a supernova remnant, many portions of which have acquired their own individual names and catalogue identifiers.
The source supernova was a star 20 times more massive than the Sun which exploded between 10,000 and 20,000 years ago. At the time of explosion, the supernova would have appeared brighter than Venus in the sky, and visible in daytime.
NGC 6729 (also known as Caldwell 68) is a reflection/emission nebula in the constellation Corona Australis.
It was discovered by Johann Friedrich Julius Schmidt in 1861.
This fan-shaped nebula opens from the star R Coronae Australis toward the star T CrA to the south-east.
R CrA is a pre-main-sequence star in the Corona Australis molecular complex, one of the closer star-forming regions of the galaxy at a distance of 130 pc.
ANGC 6193 (also known as Caldwell 82) is open cluster containing 27 stars in the constellation Ara, visible to the unaided eye.
NGC 6193 lies at the center of the Ara OB1 association, which extends over a square degree.
The cluster is associated with (and provides the energizing radiation for) neighboring regions of the nebulosity NGC 6188.
NGC 1275 (also known as Perseus A or Caldwell 24) is a type 1.5 Seyfert galaxy located around 237 million light-years away in the direction of the constellation Perseus.
NGC 1275 corresponds to the radio galaxy Perseus A and is situated near the center of the large Perseus Cluster of galaxies. NGC 1275 consists of two galaxies, a central type-cD galaxy in the Perseus Cluster, and a so-called “high velocity system” (HVS) which lies in front of it.
The HVS is moving at 3000 km/s towards the dominant system, and is believed to be merging with the Perseus Cluster.
Hubble´s Variable Nebula
NGC 2261 (also known as Hubble’s Variable Nebula or Caldwell 46) is a variable nebula located in the constellation Monoceros.
The nebula is illuminated by the star R Monocerotis (R Mon), which is not directly visible itself.
The star R Monocerotis has lit up a nearby cloud of gas and dust, but the shape and brightness slowly changes visibly even in small telescopes over weeks and months, and the nebula looks like a small comet.
One explanation proposed for the variability is that dense clouds of dust near R Mon periodically block the illumination from the star.This casts a temporary shadow on the nearby clouds.
North America Nebula
The North America Nebula (NGC 7000 or Caldwell 20) is an emission nebula in the constellation Cygnus, close to Deneb (the tail of the swan and its brightest star).
The shape of the nebula resembles that of the continent of North America, complete with a prominent Gulf of Mexico.
The North America Nebula covers a region more than ten times the area of the full moon, but its surface brightness is low, so normally it cannot be seen with the unaided eye.
NGC 281, IC 11 or Sh2-184 is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way’s Perseus Spiral Arm.
This 20×30 arcmin sized nebulosity is also associated with open cluster IC 1590, several Bok globules and the multiple star, B 1. It collectively forms Sh2-184, spanning over a larger area of 40 arcmin.
A recent distance from radio parallaxes of water masers at 22 GHz made during 2014 is estimated it lies 2.82±0.20 kpc. (9200 ly.) from us.
Lady Lucas quieted her fears a little by starting the idThe Saturn Nebula (also known as NGC 7009 or Caldwell 55) is a planetary nebula in the constellation Aquarius. It appears as a greenish-yellowish hue in a small amateur telescope.
It was discovered by William Herschel on September 7, 1782, using a telescope of his own design in the garden at his home in Datchet, England, and was one of his earliest discoveries in his sky survey.
The nebula was originally a low-mass star that ejected its layers into space, forming the nebula.
The central star is now a bright white dwarf star of apparent magnitude 11.5. The Saturn Nebula gets its name from its superficial resemblance to the planet
NGC 2359 (also known as Thor’s Helmet) is an emission nebula[ in the constellation Canis Major. The nebula is approximately 3,670 parsecs (11.96 thousand light years) away and 30 light-years in size.
The central star is the Wolf-Rayet star WR7, an extremely hot star thought to be in a brief pre-supernova stage of evolution.
It is similar in nature to the Bubble Nebula, but interactions with a nearby large molecular cloud are thought to have contributed to the more complex shape and curved bow-shock structure of Thor’s Helmet.
It is also catalogued as Sharpless 2-298 and Gum 4.
Sh 2 – 297
Sh2-297 (also known as Sharpless 297) is an emission nebula in the constellation Canis Major. The region was catalogued in 1959 in the extended seconded edition of the Sharpless catalogue.
This area is part of the Canis Major OB1 Association, and is a very active area of new star formation.
Studies in 1988 found that the bright star illuminating the nebula was 8th magnitude HD 53623 / HIP 34178 with spectral class B1II/III.
Later in 2004 it was shown that there was embedded a cold but massive Young Stellar Object or YSO within Sh2-297 near the edge of one of the dark rifts.
IC 2177 is a region of nebulosity that lies along the border between the constellations Monoceros and Canis Major. It is a roughly circular H II region centered on the Be star HD 53367.
This nebula was discovered by Welsh amateur astronomer Isaac Roberts and was described by him as “pretty bright, extremely large, irregularly round, very diffuse.”
The name Seagull Nebula is sometimes applied by amateur astronomers to this emission region, although it more properly includes the neighboring regions of star clusters, dust clouds and reflection nebulae.
This latter region includes the open clusters NGC 2335 and NGC 2343.
Skull and Crossbones Nebula
NGC 2467, nicknamed the “Skull and Crossbones Nebula is a star-forming region whose appearance has occasionally also been likened to that of a colorful mandrill.
It includes areas where large clouds of hydrogen gas incubate new stars. This region was one of the areas featured in the book Hubble’s Universe: Greatest Discoveries and Latest Images by Terence Dickinson.
NGC 2467 had long been considered to be the nucleus of the Puppis I association.
However, NGC 2467 does not represent a distinct open cluster; rather, it represents a superimposition of several stellar groups along the same approximate line of sight that have distinctly different distances and distinctly different radial velocities.
NGC 2736 (also known as the Pencil Nebula) is a small part of the Vela Supernova Remnant, located near the Vela Pulsar in the constellation Vela. The nebula’s linear appearance triggered its popular name.
It resides about 815 light-years (250 parsecs) away from the Solar System. It is thought to be formed from part of the shock wave of the larger Vela Supernova Remnant.
The Pencil Nebula is moving at roughly 644,000 kilometers per hour (400,000 miles per hour).
On 1 March 1835, John Herschel discovered this object at the Cape of Good Hope and described it as “eeF, L, vvmE; an extraordinary long narrow ray of excessively feeble light; position 19 ±.
RCW 38 is an HII region containing a massive star cluster located approximately 5,500 light years away from Earth in the direction of the constellation Vela (known as, the Sails).
The stars were very recently formed, and are still enshrouded within the dark cloud in which they were born.
The star cluster is surrounded by clouds of brightly glowing gas and is composed of several short-lived massive stars, hundreds of young stars, and many protostars.
The star cluster several O-type stars with masses much larger than the sun. When these stars die, likely before the dispersal of the cluster, they will explode as supernovae.
RCW 86 (SN 185) was a transient astronomical event observed in AD 185, likely a supernova. The transient occurred in the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA 14h 43m Dec −62° 30′, in Circinus.
This “guest star” was observed by Chinese astronomers in the Book of Later Han (后汉书),and might have been recorded in Roman literature.
It remained visible in the night sky for eight months. This is believed to be the first supernova for which records exist.
RCW 120 is an emission nebula and H II region in the southern Milky Way and located some 4,300 light-years from Earth.
Its designation appears in the RCW Catalogue published in 1960, whose circular diameter size is 6 arcmin. It also catalogued as Sh 2-3 and Gum 58.
Veta S. Avedisova considers RCW 120 is being ionised by the O8 V star CD -38 11636 and the B2 V star VDBH 84B, and places the nebula in the star formation region SFR 348.26+0.47 along with 3 masers and the radio HII region CH87 347.386+0.266.
The Herschel infra-red telescope’s image shows an embryonic star that is likely to become one of the brightest stars in our Galaxy at some time within the next few hundred thousand years.
Spiral Planetary Nebula
NGC 5189 (Gum 47, IC 4274, nicknamed Spiral Planetary Nebula) is a planetary nebula in the constellation Musca.
It was discovered by James Dunlop on 1 July 1826, who catalogued it as Δ252.
For many years, well into the 1960s, it was thought to be a bright emission nebula. It was Karl Gordon Henize in 1967 who first described NGC 5189 as quasi-planetary based on its spectral emissions.
Seen through the telescope it seems to have an S shape, reminiscent of a barred spiral galaxy.
The S shape, together with point-symmetric knots in the nebula, have for a long time hinted to astronomers that a binary central star is present.
Simeis 147, also known as the Spaghetti Nebula, SNR G180.0-01.7 or Sharpless 2-240, is a supernova remnant (SNR) in the Milky Way, straddling the border between the constellations Auriga and Taurus.
Discovered in 1952 at the Crimean Astrophysical Observatory using a 25-inch Schmidt-Cassegrain telescope, it is difficult to observe due to its extremely low brightness. The nebulous area is fairly large with an almost spherical shell and filamentary structure.
The remnant has an apparent diameter of approximately 3 degrees, an estimated distance of approximately 3000 (±350) light-years, and an age of approximately 40,000 years.
It is believed that after its stellar explosion a rapidly spinning neutron star known as pulsar PSR J0538+2817 was left behind in the nebula core, emitting a strong radio signal.
N49 or LMC N49 is the brightest supernova remnant in the Large Magellanic Cloud, approximately 160,000 light-years from Earth.
Its form has been assessed to be roughly 5,000 years old.
The latest pictures of N49 by the Chandra X-ray Observatory have revealed a bullet-shaped object traveling at about 5 million miles an hour away from a bright X-ray and gamma-ray point source, probably a neutron star with an extremely powerful magnetic field, known as a soft gamma repeater.
A particularly strong gamma-ray burst from LMC N49 was detected on March 5, 1979.
G292.0+01.8 is a supernova remnant located in the constellation Centaurus. It first gained notice as a strong radio source, and eventually deep images revealed a hot optical nebula at the location. It lies about 15,000 light years away.
The remnant’s spectrum shows no detectable lines of hydrogen and helium and the presence of only oxygen and neon.
The assumption is that a massive star burned through its hydrogen, producing oxygen and neon, and exploded before processing any heavier elements. It must have taken place relatively recently, as the oxygen and neon have not yet mixed with the interstellar hydrogen.
W49B (also known as SNR G043.3-00.2 or 3C 398) is a nebula in Westerhout 49 (W49). The nebula is a supernova remnant, probably from a type Ib or Ic supernova that occurred around 1,000 years ago.
It may have produced a gamma-ray burst and is thought to have left a black hole remnant.
W49B is a supernova remnant (SNR) located roughly 33,000 light-years from Earth, Radio wavelengths show a shell four arc minutes across. There are infrared “rings” (about 25 light-years in diameter) forming a “barrel”, and intense X-ray radiation coming from forbidden emission of nickel and iron in a bar along its axis.
W49B is also one of the most luminous SNRs in the galaxy at gamma-ray wavelengths. It is invisible at optical wavelengths.
SN 1006 was a supernova that is likely the brightest observed stellar event in recorded history, reaching an estimated −7.5 visual magnitude, and exceeding roughly sixteen times the brightness of Venus.
Appearing between April 30 and May 1, 1006 AD in the constellation of Lupus, this “guest star” was described by observers across the modern day countries of China, Japan, Iraq, Egypt, and the continent of Europe, and possibly recorded in North American petroglyphs.
Some reports state it was clearly visible in the daytime.
Modern astronomers now consider its distance from Earth to be about 7,200 light-years.
E0102, short for 1E 0102.2-7219, is the remnant of a supernova that exploded in the Small Magellanic Cloud, a neighbouring galaxy of the Milky Way.
The supernova was caused when a star much more massive than the Sun collapsed under its own gravity. The explosion would have been visible from the Southern Hemisphere of the Earth over 1000 years ago.
The appearance of E0102 is best explained by a model in which the ejecta is shaped like a cylinder that is being viewed almost exactly end-on.
SN 1993J is a supernova observed in the galaxy M81. It was discovered on 28 March 1993 by F. Garcia in Spain. At the time, it was the second-brightest type II supernova observed in the twentieth century behind SN 1987A.
The spectral characteristics of the supernova changed over time. Initially, it looked more like a type II supernova (a supernova formed by the explosion of a giant star) with strong hydrogen spectral line emission, but later the hydrogen lines faded and strong helium spectral lines appeared, making the supernova look more like a type Ib.
SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf satellite galaxy of the Milky Way. It occurred approximately 51.4 kiloparsecs (168,000 light-years) from Earth and was the closest observed supernova since Kepler’s Supernova.
1987A’s light reached Earth on February 23, 1987, and as the earliest supernova discovered that year, was labeled “1987A”. Its brightness peaked in May, with an apparent magnitude of about 3.
It was the first supernova that modern astronomers were able to study in great detail, and its observations have provided much insight into core-collapse supernovae.
SN 1987A provided the first opportunity to confirm by direct observation the radioactive source of the energy for visible light emissions, by detecting predicted gamma-ray line radiation from two of its abundant radioactive nuclei.
This proved the radioactive nature of the long-duration post-explosion glow of supernovae.
The Andromeda Galaxy
The Andromeda Galaxy , also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula , is a barred spiral galaxy approximately 2.5 million light-years (770 kiloparsecs) from Earth and the nearest major galaxy to the Milky Way.
The galaxy’s name stems from the area of Earth’s sky in which it appears, the constellation of Andromeda, which itself is named after the Ethiopian (or Phoenician) princess who was the wife of Perseus in Greek mythology.
The Antennae Galaxies (also known as NGC 4038/NGC 4039 or Caldwell 60/Caldwell 61) are a pair of interacting galaxies in the constellation Corvus.
They are currently going through a starburst phase, in which the collision of clouds of gas and dust, with entangled magnetic fields, causes rapid star formation. They were discovered by William Herschel in 1785.
The Antennae Galaxies are undergoing a galactic collision.
Located in the NGC 4038 group with five other galaxies, these two galaxies are known as the Antennae Galaxies because the two long tails of stars, gas and dust ejected from the galaxies as a result of the collision resemble an insect’s antennae.
NGC 4622 is a face-on unbarred spiral galaxy with a very prominent ring structure located in the constellation Centaurus. The galaxy is a member of the Centaurus Cluster.
The spiral galaxy, NGC 4622 (also called Backward galaxy), lies approx. 111 million light years away from Earth in the constellation Centaurus.
NGC 4622 is an example of a galaxy with leading spiral arms.
In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation.
In NGC 4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation.
Black Eye Galaxy
The Black Eye Galaxy (also called Evil Eye Galaxy and designated Messier 64, M64, or NGC 4826) is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices.
It was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier the next year.
A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the “Black Eye” or “Evil Eye” galaxy.
Messier 81 (also known as NGC 3031 or Bode’s Galaxy) is a grand design spiral galaxy about 12 million light-years away, with a diameter of 90,000 light years, in the constellation Ursa Major.
Due to its proximity to our galaxy, large size, and active galactic nucleus (which harbors a 70 million M☉ supermassive black hole), Messier 81 has been studied extensively by professional astronomers.
The galaxy’s large size and relatively high brightness also makes it a popular target for amateur astronomers.
Messier 81 was first discovered by Johann Elert Bode on 31 December 1774.
NGC 4567 and NGC 4568 (nicknamed the Butterfly Galaxies or Siamese Twins) are a set of unbarred spiral galaxies about 60 million light-years away in the constellation Virgo.
They were both discovered by William Herschel in 1784. They are part of the Virgo Cluster of galaxies. Only one supernova (SN 2004cc) was observed in the Butterfly Galaxies until March 31, 2020, when the Zwicky Transient Facility detected the rapidly-rising supernova 2020fqv.
These galaxies are in the process of colliding and merging with each other, as studies of their distributions of neutral and molecular hydrogen show, with the highest star-formation activity in the part where they overlap.
However, the system is still in an early phase of interaction.
The Cartwheel Galaxy (also known as ESO 350-40 or PGC 2248) is a lenticular galaxy and ring galaxy about 500 million light-years away in the constellation Sculptor.
It is an estimated 150,000 light-years diameter, and has a mass of about 2.9–4.8 × 109 solar masses; its outer ring has a circular velocity of 217 km/s.
It was discovered by Fritz Zwicky in 1941.
An estimation of the galaxy’s span resulted in a conclusion of 150,000 light years, which is a moderate amount smaller than the Milky Way.
Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major.
A member of the M81 Group, it is about five times more luminous than the Milky Way and has a center one hundred times more luminous.
The starburst activity is thought to have been triggered by interaction with neighboring galaxy M81. As the closest starburst galaxy to Earth, M82 is the prototypical example of this galaxy type.
SN 2014J, a type Ia supernova, was discovered in the galaxy on 21 January 2014. In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated M82 X-2.
The Circinus Galaxy
The Circinus Galaxy is a Seyfert galaxy in the constellation of Circinus. It is located 4 degrees below the Galactic plane, and, at a distance of 4.0 Mpc (13 Mly), is one of the closest major galaxies to the Milky Way.
The galaxy is undergoing tumultuous changes, as rings of gas are likely being ejected from the galaxy. Its outermost ring is 1400 light-years across while the inner ring is 260 light-years across.
Although the Circinus galaxy can be seen using a small telescope, it was not noticed until 1977 because it lies close to the plane of the Milky Way and is obscured by galactic dust.
Coma Pinwheel Galaxy
Messier 99 or M99, also known as NGC 4254, is a grand design spiral galaxy in the northern constellation Coma Berenices approximately 15,000,000 parsecs (49,000,000 light-years) from the Milky Way.
It was discovered by Pierre Méchain on 17 March 1781.
The discovery was then reported to Charles Messier, who included the object in the Messier Catalogue of comet-like objects. It was one of the first galaxies in which a spiral pattern was seen. This pattern was first identified by Lord Rosse in the spring of 1846.
The Comet Galaxy, a spiral galaxy located 3.2 billion light-years from Earth, in the galaxy cluster Abell 2667, was found with the Hubble Space Telescope.
This galaxy has slightly more mass than our Milky Way. It was detected on 2 March 2007.
This unique spiral galaxy, which is situated 3.2 billion light-years from the Earth, has an extended stream of bright blue knots and diffuse wisps of young stars.
It rushes at 3.5 million km/h through the cluster Abell 2667 and therefore, like a comet, shows a tail, with a length of 600,000 light-years.
Cosmos Redshift 7 Galaxy
Cosmos Redshift 7 (also known as COSMOS Redshift 7, Galaxy Cosmos Redshift 7, Galaxy CR7 or CR7) is a high-redshift Lyman-alpha emitter galaxy.
At a redshift z = 6.6, the galaxy is observed as it was about 800 million years after the Big Bang, during the epoch of reionisation. With a light travel time of 12.9 billion years, it is one of the oldest, most distant galaxies known.
CR7 shows some of the expected signatures of Population III stars i.e. the first generation of stars produced during early galaxy formation. These signatures were detected in a bright pocket of blue stars; the rest of the galaxy contains redder Population II stars.
Eye of Sauron Galaxy
NGC 4151 is an intermediate spiral Seyfert galaxy with weak inner ring structure located 15.8 megaparsecs (52 million light-years) from Earth in the constellation Canes Venatici.
The galaxy was first mentioned by William Herschel on March 17, 1787; it was one of the two Seyfert galaxies described in the paper which defined the term.
It is one of the nearest galaxies to Earth to contain an actively growing supermassive black hole; it was speculated that the nucleus may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting with a 15.8-year period. This is, however, still a matter of active debate.
NGC 6946, also known as the Fireworks Galaxy or Caldwell 12, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus.
Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs,xx similar to the distance of M101 (NGC 5457) in the constellation Ursa Major.
Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
The Hockey Stick Galaxy
NGC 4656/57 is a highly warped barred spiral galaxy located in the constellation Canes Venatici and is sometimes informally called the Hockey Stick Galaxies or the Crowbar Galaxy.
The galaxy is a member of the NGC 4631 Group. A Luminous Blue Variable in “super-outburst” was discovered in NGC 4656/57 on March 21, 2005.
Hoag’s Object is a non-typical galaxy of the type known as a ring galaxy. The galaxy is named after Arthur Hoag who discovered it in 1950 and identified it as either a planetary nebula or a peculiar galaxy with eight billion stars, spanning roughly 100,000 light years.
A nearly perfect ring of young hot blue stars circles the older yellow nucleus of this ring galaxy c. 600 million light-years away in the constellation Serpens.
The diameter of the 6 arcsecond inner core of the galaxy is about 17±0.7 kly (5.3±0.2 kpc) while the surrounding ring has an inner 28″ diameter of 75±3 kly (24.8±1.1 kpc) and an outer 45″ diameter of 121±4 kly (39.9±1.7 kpc).
The Large Magellanic Cloud
The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000 light-years), the LMC is the second or third closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal (~16 kpc) and the possible dwarf irregular galaxy known as the Canis Major Overdensity.
Based on readily visible stars and a mass of approximately 10 billion solar masses, the diameter of the LMC is about 14,000 light-years (4.3 kpc).
AM 0644-741, also known as the Lindsay-Shapley Ring, is an unbarred lenticular galaxy, and a ring galaxy, which is 300 million light-years away in the southern constellation Volans.
The yellowish nucleus was once the center of a normal spiral galaxy, and the ring which currently surrounds the center is 150,000 light years in diameter.
The ring is theorized to have formed by a collision with another galaxy, which triggered a gravitational disruption that caused dust in the galaxy to condense and form stars, which forced it to then expand away from the galaxy and create a ring.
Little Sombrero Galaxy
NGC 7814 (also known as UGC 8 or Caldwell 43) is a spiral galaxy about 40 million light-years away in the constellation Pegasus.
The galaxy is seen edge-on from Earth. It is sometimes referred to as “the little sombrero”, a miniature version of Messier 104.
The star field behind NGC 7814 is known for its density of faint, remote galaxies as can be seen in the image here – in the same vein as the Hubble Deep Field.
Malin 1 Galaxy
Malin 1 is a giant low surface brightness (LSB) spiral galaxy. It is located 1.19 billion light-years (366 Mpc) away in the constellation Coma Berenices, near the North Galactic Pole.
As of February 2015, it is the largest known spiral galaxy, with an approximate diameter of 650,000 light-years (200,000 pc), thus over three times the diameter of our Milky Way.
It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist.
Its high surface brightness central spiral is 30,000 light-years (9,200 pc) across, with a bulge of 10,000 light-years (3,100 pc). The central spiral is a SB0a type barred-spiral.
NGC 4194, the Medusa merger, is a pair of interacting galaxies in the constellation Ursa Major.
A region of extreme star formation 500 ly (150 pc) across exists in the center of the Eye of Medusa, the central gas-rich region.
The Sculptor Dwarf Galaxy
The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy, and formerly as the Sculptor System) is a dwarf spheroidal galaxy that is a satellite of the Milky Way.
The galaxy lies within the constellation Sculptor.
It was discovered in 1937 by American astronomer Harlow Shapley using the 24-inch Bruce refractor at Boyden Observatory. The galaxy is located about 290,000 light-years away from the Solar System.
The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe.
NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years away, they began the process of colliding and merging.
Their name refers to the long tails produced by tidal action—the relative difference between gravitational pulls on the near and far parts of each galaxy—known here as a galactic tide.
It is a possibility that both galaxies, which are members of the Coma cluster, have experienced collision, and will continue colliding until they coalesce.
The Small Magellanic Cloud
The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a diameter of about 7,000 light-years, contains several hundred million stars, and has a total mass of approximately 7 billion solar masses.
The SMC contains a central bar structure, and astronomers speculate that it was once a barred spiral galaxy that was disrupted by the Milky Way to become somewhat irregular.
At a distance of about 200,000 light-years, the SMC is among the nearest intergalactic neighbors of the Milky Way and is one of the most distant objects visible to the naked eye.
There is a bridge of gas connecting the Small Magellanic Cloud with the Large Magellanic Cloud (LMC), which is evidence of tidal interaction between the galaxies.
Mayall’s Object (also classified under the Atlas of Peculiar Galaxies as Arp 148) is the result of two colliding galaxies located 500 million light years away within the constellation of Ursa Major.
It was discovered by American astronomer Nicholas U. Mayall of the Lick Observatory on 13 March 1940, using the Crossley reflector.
When first discovered, Mayall’s Object was described as a peculiar nebula, shaped like a question mark.
Originally theorized to represent a galaxy reacting with the intergalactic medium, it is now thought to represent the collision of two galaxies, resulting in a new object consisting of a ring-shaped galaxy with a tail emerging from it.
The Milky Way Galaxy
The Milky Way is the galaxy that contains our Solar System, with the name describing the galaxy’s appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye.
From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within.
NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximately 10.
It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel, it is a prominent example of an edge-on spiral galaxy.
NGC 4565 is a giant spiral galaxy more luminous than the Andromeda Galaxy. Much speculation exists in literature as to the nature of the central bulge.
In the absence of clear-cut dynamical data on the motions of stars in the bulge, the photometric data alone cannot adjudge among various options put forth.
The Wolf–Lundmark–Melotte (WLM) is a barred irregular galaxy discovered in 1909 by Max Wolf, located on the outer edges of the Local Group.
The discovery of the nature of the galaxy was accredited to Knut Lundmark and Philibert Jacques Melotte in 1926. It is in the constellation Cetus.
In 1994, A. E. Dolphin used the Hubble Space Telescope to create a color–magnitude diagram for WLM. It showed that around half of all the star formation in this galaxy occurred during a starburst that started ~13 Gyr ago.
The Pinwheel Galaxy
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy 21 million light-years (6.4 megaparsecs) away from Earth in the constellation Ursa Major.
It was discovered by Pierre Méchain in 1781.
M101 is a large galaxy, with a diameter of 170,000 light-years. By comparison, the Milky Way has a diameter of 100,000 light-years.
It has around a trillion stars, twice the number in the Milky Way. It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.
The Sculptor Galaxy
The Sculptor Galaxy (also known as the Silver Coin, Silver Dollar Galaxy, NGC 253, or Caldwell 65) is an intermediate spiral galaxy in the constellation Sculptor.
The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.
The Sculptor Galaxy is located at the center of the Sculptor Group, one of the nearest groups of galaxies to the Milky Way.
The Sombrero Galaxy
The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a spiral galaxy in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs (31.1 million light-years) from our galaxy, within the local supercluster.
It has a diameter of approximately 15 kiloparsecs (49,000 light-years), 0.3x times the size of the Milky Way.
Southern Pinwheel Galaxy
Messier 83 or M83, also known as the Southern Pinwheel Galaxy and NGC 5236, is a barred spiral galaxy approximately 15 million light-years away in the constellation borders of Hydra and Centaurus.
Nicolas Louis de Lacaille discovered M83 on February 23, 1752 at the Cape of Good Hope.
Charles Messier added it to his catalogue of nebulous objects (now known as the Messier Catalogue) in March 1781.
Lady Lucas quieted her fears a little by starting the idea of his being gone to London only to get a large party for the ball.
The Tadpole Galaxy
The Tadpole Galaxy is a disrupted barred spiral galaxy located 420 million light-years from Earth in the northern constellation Draco.
Its most dramatic feature is a trail of stars about 280,000 light-years long. Its size has been attributed to a merger with a smaller galaxy that is believed to have occurred about 100 million years ago. It is filled with bright blue star clusters.
It is hypothesized that a more compact intruder galaxy crossed in front of the Tadpole Galaxy – from left to right from the perspective of Earth – and was slung around behind the Tadpole by their mutual gravitational attraction.
During this close encounter, tidal forces drew out the spiral galaxy’s stars, gases and dust, forming the conspicuous tail.
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598.
The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Milky Way and the Andromeda Galaxy (the largest). It is one of the most distant permanent objects that can be viewed with the naked eye.
The galaxy is the smallest spiral galaxy in the Local Group and is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky. It also has an H II nucleus.
With a diameter of about 60,000 light-years, the Triangulum Galaxy is the third largest member of the Local Group of galaxies, roughly 60% the size of the Milky Way.
The Whirlpool Galaxy
The Whirlpool Galaxy, also known as Messier 51a, M51a, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy.
Its distance is estimated to be 31 million light-years away from Earth.
The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars.
The Whirlpool Galaxy has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.
is a short-period comet visible from Earth every 75–76 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the only naked-eye comet that can appear twice in a human lifetime.
Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061.
Halley’s periodic returns to the inner Solar System have been observed and recorded by astronomers around the world since at least 240 BC.
But it was not until 1705 that the English astronomer Edmond Halley understood that these appearances were reappearances of the same comet.
Comet NEOWISE is a long period comet with a near-parabolic orbit discovered on March 27, 2020, by astronomers during the NEOWISE mission of the Wide-field Infrared Survey Explorer (WISE) space telescope.
At that time, it was an 18th-magnitude object, located 2 AU (300 million km; 190 million mi) away from the Sun and 1.7 AU (250 million km; 160 million mi) away from Earth.
NEOWISE is known for being the brightest comet in the northern hemisphere since Comet Hale–Bopp in 1997.
Under dark skies, it could be seen with the naked eye and remained visible to the naked eye throughout July 2020.
Comet Hyakutake (C/1996 B2) is a comet, discovered on 31 January 1996, that passed very close to Earth in March of that year. It was dubbed The Great Comet of 1996; its passage near the Earth was one of the closest cometary approaches of the previous 200 years.
Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale–Bopp, which was approaching the inner Solar System at the time.
Comet Encke is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PANSTARRS has a period of 3.2 years.)
Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke.
Like Halley’s Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer.
Comet Kohoutek (C/1973 E1) was first sighted on 7 March 1973 by Czech astronomer Luboš Kohoutek. It attained perihelion on 28 December that same year.
Comet Kohoutek is a long-period comet; its previous apparition was about 150,000 years ago, and its next apparition will be in about 75,000 years.
At its apparition in 1973, it had a hyperbolic trajectory (e > 1) due to gravitational perturbations from giant planets.
Comet McNaught, (C/2006 P1) also known as Great Comet of 2007 is a non-periodic comet discovered on 7 August 2006 by British-Australian astronomer Robert H. McNaught using the Uppsala Southern Schmidt Telescope.
It was the brightest comet in over 40 years, and was easily visible to the naked eye for observers in the Southern Hemisphere in January and February 2007. Comet C/2006 P1 took millions of years coming directly from the Oort cloud.
Comet West (C/1975 V1, 1976 VI, and 1975n) was a comet described as one of the brightest objects to pass through the inner Solar System in 1976. It is often described as a “great comet.”
It was discovered photographically by Richard M. West, of the European Southern Observatory, on August 10, 1975.
The comet came to perihelion (closest approach to the Sun) on February 25, 1976.
With a nearly parabolic trajectory, estimates for the orbital period of this comet have varied from 254,000 to 558,000 years.
As the comet passed within 30 million km of the Sun, the nucleus was observed to split into four fragments.
Comet Hale–Bopp (C/1995 O1) is a comet that was perhaps the most widely observed of the 20th century and one of the brightest seen for many decades.
The comet’s orbit was shortened considerably to a period of roughly 2,533 years, and it will next return to the inner Solar System around the year 4385. Its greatest distance from the Sun (aphelion) will be about 370 AU, reduced from about 525 AU.
Alan Hale and Thomas Bopp discovered Comet Hale–Bopp separately on July 23, 1995, before it became visible to the naked eye.
It was visible to the naked eye for a record 18 months, twice as long as the Great Comet of 1811, the previous record holder. Accordingly, Hale–Bopp was dubbed the great comet of 1997.
Comet Ikeya–Seki (C/1965 S1) was a long-period comet discovered independently by Kaoru Ikeya and Tsutomu Seki.
First observed as a faint telescopic object on September 18, 1965, the first calculations of its orbit suggested that on October 21, it would pass just 450,000 km above the Sun’s surface, and would probably become extremely bright.
In Japan, where it reached perihelion at local noon, it was seen shining at magnitude −10. It proved to be one of the brightest comets seen in the last thousand years, and is sometimes known as the Great Comet of 1965.
Types of Galaxies
Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters.
Barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about half of all spiral galaxies. Bars generally affect both the motions of stars and interstellar gas within spiral galaxies and can affect spiral arms as well. The Milky Way Galaxy is classified as a barred spiral galaxy.
Elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth. Most elliptical galaxies are composed of older, low-mass stars, with a sparse interstellar medium and minimal star formation activity, and they tend to be surrounded by large numbers of globular clusters.
Irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.
Lenticular galaxy is a type of galaxy intermediate between an elliptical and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation.
Peculiar galaxy is a galaxy of unusual size, shape, or composition. Between five and ten percent of known galaxies are categorized as peculiar. When two galaxies come close to each other, their mutual gravitational forces can cause them to acquire highly irregular shapes.
Kilonova is a transient astronomical event that occurs in a compact binary system when two neutron stars or a neutron star and a black hole merge into each other.
Kilonovae are thought to emit short gamma-ray bursts and strong electromagnetic radiation due to the radioactive decay of heavy r-process nuclei that are produced and ejected fairly isotropically during the merger process.
The first observational suggestion of a kilonova came in 2008 following the short-hard gamma-ray burst GRB 080503, where a faint object appeared in optical and infrared light after one day and rapidly faded.
Aurora is a natural light predominantly seen in high-latitude regions (around the Arctic and Antarctic).
Auroras are the result of disturbances in the magnetosphere caused by solar wind.
These disturbances alter the trajectories of charged particles in the magnetospheric plasma.
These particles, mainly electrons and protons, precipitate into the upper atmosphere (thermosphere/exosphere).
The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles.
Most of the planets in the Solar System, some natural satellites, brown dwarfs, and even comets also host auroras.
Exoplanet is a planet outside the Solar System.
The first possible evidence of an exoplanet was noted in 1917, but was not recognized as such.
The first confirmation of detection occurred in 1992. The discovery of exoplanets has intensified interest in the search for extraterrestrial life.
There is special interest in planets that orbit in a star’s habitable zone, where it is possible for liquid water, a prerequisite for life on Earth, to exist on the surface.
Newton’s cradle is a device that demonstrates the conservation of momentum and the conservation of energy with swinging spheres.
When one sphere at the end is lifted and released, it strikes the stationary spheres, transmitting a force through the stationary spheres that pushes the last sphere upward.
The last sphere swings back and strikes the nearly stationary spheres, repeating the effect in the opposite direction.
Mushroom cloud is a distinctive mushroom-shaped flammagenitus cloud of debris, smoke and usually condensed water vapor resulting from a large explosion.
The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same effect.
They can be caused by powerful conventional weapons, like thermobaric weapons.
Some volcanic eruptions and impact events can produce natural mushroom clouds.
Sound is defined as Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces, or the superposition of such propagated oscillation.
Auditory sensation evoked by the oscillation described in.
Sound can be viewed as a wave motion in air or other elastic media. In this case, sound is a stimulus.
Sound can also be viewed as an excitation of the hearing mechanism that results in the perception of sound.
In this case, sound is a sensation.
Large Hadron Collider (LHC)
LHC is the world’s largest and highest-energy particle collider. It was built by the European Organization for Nuclear Research (CERN).
It lies in a tunnel 27 kilometres (17 mi) in circumference and as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva.
The first collisions were achieved in 2010 at an energy of 3.5 teraelectronvolts (TeV) per beam, about four times the previous world record. After upgrades it reached 6.5 TeV per beam (13 TeV total collision energy, the present world record).
Spacetime is any mathematical model which fuses the three dimensions of space and the one dimension of time into a single four-dimensional manifold.
Spacetime diagrams can be used to visualize relativistic effects, such as why different observers perceive differently where and when events occur.