IC 10

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IC 10
IC10 BVHa.jpg
Irregular Galaxy IC 10
Observation data (J2000 epoch)
Constellation Cassiopeia
Right ascension 00h 20m 17.3s [1]
Declination +59° 18′ 14″ [1]
Redshift 0.001161±0.000003 [1]
Distance 2.5 ± 0.5 Mly (750 ± 150 kpc) [2]
Apparent magnitude  (V)10.4 ± 0.2 [3]
Characteristics
Type dIrr IV/BCD [1]
Size5000 light years (diameter) [4]
Apparent size  (V)6.8′ × 5.9′ [1]
Notable featuresmild starburst galaxy
Other designations
UGC 192, [1] PGC 1305 [1]

IC 10 is an irregular galaxy in the constellation Cassiopeia. It was discovered by Lewis Swift in 1887 [5] and in 1935 Nicholas Mayall became the first to suggest that the object is extragalactic. Edwin Hubble suspected it might belong to the Local Group of galaxies, but its status remained uncertain for decades. The radial velocity of IC 10 was measured in 1962, and it was found to be approaching the Milky Way at approximately 350 km/s, strengthening the evidence for its membership in the Local Group. [5] Its membership in the group was finally confirmed in 1996 by direct measurements of its distance based on observations of Cepheids; most estimates place the galaxy 2–3 million light years from Earth, with some estimates ranging from 1.5–4.5 million light years. [6] Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the Milky Way and is therefore heavily obscured by interstellar matter. [7]

Contents

The apparent distance between IC 10 and the Andromeda Galaxy is about the same as the apparent distance between the Andromeda Galaxy and the Triangulum Galaxy, which suggests that IC 10 may belong to the M31 subgroup. [7]

IC 10 is the only known starburst galaxy in the Local Group of galaxies; it has many more Wolf–Rayet stars per square kiloparsec (5.1 stars/kpc2) than the Large Magellanic Cloud (2.0 stars/kpc2) or the Small Magellanic Cloud (0.9 stars/kpc2). Although the galaxy has a luminosity similar to the SMC, it is considerably smaller, with an estimated diameter of around 5000 light years. [8] Its higher metallicity compared to the SMC suggests that star formation activity has continued for a longer time period. The H II regions in IC 10 have all formed recently, within the last 10 Myr. [9] The evolutionary status of the Wolf–Rayet stars suggests that they all formed in a relatively short timespan. The ratio between the two types of Wolf–Rayet stars (WC stars and WN stars) in IC 10 is very different from the ratio in other galaxies in the Local Group, which may be somehow due to the starburst nature of the galaxy. Currently, the galaxy produces stars at the rate of 0.04–0.08 solar masses per year, which means that the gas supply in the galaxy can last for only a few billion years longer. [7]

Observations of IC 10 in the far-infrared show that the dust in this mild starburst galaxy is deficient in small grains. [10] It is hypothesized that any small grains that formerly existed were destroyed by strong ultraviolet radiation in the areas around the hot luminous stars that were formed in the galaxy's recent burst of star formation. [11]

The galaxy has a huge envelope of hydrogen gas, with an apparent size measuring 68′ × 80′, which is far larger than the apparent size of the galaxy in visible light (5.5′ × 7.0′). IC 10 is also unusual in the respect that the visible part of the galaxy seems to rotate in a different direction than the outer envelope. [7] It has an H II nucleus. [12]

Related Research Articles

<span class="mw-page-title-main">Local Group</span> Group of galaxies that includes the Milky Way

The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×1019 kilometres), and a total mass of the order of 2×1012 solar masses (4×1042 kg). It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kiloparsecs (3×10^6 ly; 2×1019 km) and are moving toward one another with a velocity of 123 km/s. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

<span class="mw-page-title-main">Small Magellanic Cloud</span> Dwarf irregular galaxy, satellite galaxy of the Milky Way

The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about 5.78 kiloparsecs (18,900 light-years), and contains several hundred million stars. It has a total mass of approximately 7 billion solar masses. 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.

<span class="mw-page-title-main">Wolf–Rayet star</span> Heterogeneous class of stars with unusual spectra

Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface enhancement of heavy elements, depletion of hydrogen, and strong stellar winds. The surface temperatures of known Wolf–Rayet stars range from 20,000 K to around 210,000 K, hotter than almost all other kinds of stars. They were previously called W-type stars referring to their spectral classification.

NGC 4631 is a barred spiral galaxy in the constellation Canes Venatici about 30 million light years away from Earth. This galaxy's slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname. Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.

<span class="mw-page-title-main">Centaurus A</span> Radio galaxy in the constellation Centaurus

Centaurus A is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance. NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target. It is only visible from the southern hemisphere and low northern latitudes.

<span class="mw-page-title-main">NGC 1569</span> Galaxy in the constellation Camelopardalis

NGC 1569 is a dwarf irregular galaxy in Camelopardalis. The galaxy is relatively nearby and consequently, the Hubble Space Telescope can easily resolve the stars within the galaxy. The distance to the galaxy was previously believed to be only 2.4 Mpc. However, in 2008 scientists studying images from Hubble calculated the galaxy's distance at nearly 11 million light-years away, about 4 million light-years farther than previously thought, meaning it is a member of the IC 342 group of galaxies.

<span class="mw-page-title-main">Tucana Dwarf</span> Dwarf galaxy in the constellation Tucana

The Tucana Dwarf Galaxy is a dwarf galaxy in the constellation Tucana. It was discovered in 1990 by R.J. Lavery of Mount Stromlo Observatory. It is composed of very old stars and is very isolated from other galaxies. Its location on the opposite side of the Milky Way from other Local Group galaxies makes it an important object for study.

<span class="mw-page-title-main">NGC 6822</span> Galaxy in the constellation Sagittarius

NGC 6822 is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.

<span class="mw-page-title-main">NGC 7331</span> Galaxy in the constellation Pegasus

NGC 7331, also known as Caldwell 30, is an unbarred spiral galaxy about 40 million light-years (12 Mpc) away in the constellation Pegasus. It was discovered by William Herschel in 1784. NGC 7331 is the brightest galaxy in the field of a visual grouping known as the NGC 7331 Group of galaxies. In fact, the other members of the group, NGC 7335, 7336, 7337 and 7340, lie far in the background at distances of approximately 300-350 million light years.

<span class="mw-page-title-main">IC 1613</span> Irregular dwarf galaxy in the constellation Cetus

IC 1613 is an irregular dwarf galaxy, visible in the constellation Cetus near the star 26 Ceti. It was discovered in 1906 by Max Wolf, and is approaching Earth at 234 km/s.

<span class="mw-page-title-main">NGC 5253</span> Irregular galaxy in the M83 group of galaxies

NGC 5253 is an irregular galaxy in the constellation Centaurus. It was discovered by William Herschel on 15 March 1787.

<span class="mw-page-title-main">NGC 4214</span> Galaxy in the constellation Canes Venatici

NGC 4214 is a dwarf barred irregular galaxy located around 10 million light-years away in the constellation Canes Venatici. NGC 4214 is a member of the M94 Group.

<span class="mw-page-title-main">NGC 346</span> Open cluster in the constellation Tucana

NGC 346 is a young open cluster of stars with associated nebula located in the Small Magellanic Cloud (SMC) that appears in the southern constellation of Tucana. It was discovered August 1, 1826 by Scottish astronomer James Dunlop. J. L. E. Dreyer described it as, "bright, large, very irregular figure, much brighter middle similar to double star, mottled but not resolved". On the outskirts of the cluster is the multiple star system HD 5980, one of the brightest stars in the SMC.

<span class="mw-page-title-main">NGC 4449</span> Galaxy in the constellation Canes Venatici

NGC 4449, also known as Caldwell 21, is an irregular Magellanic type galaxy in the constellation Canes Venatici, being located about 13 million light-years away. It is part of the M94 Group or Canes Venatici I Group that is relatively close to the Local Group hosting our Milky Way galaxy.

<span class="mw-page-title-main">NGC 1313</span> Galaxy in the constellation Reticulum

NGC 1313 is a field galaxy and a irregular galaxy discovered by the Scottish astronomer James Dunlop on 27 September 1826. It has a diameter of about 50,000 light-years, or about half the size of the Milky Way.

<span class="mw-page-title-main">NGC 376</span> Globular cluster located in the constellation Tucana

NGC 376 is a young open cluster of stars in the southern constellation of Tucana. It was discovered on September 2, 1826, by Scottish astronomer James Dunlop. Dreyer, a Danish/British astronomer, described it as a "globular cluster, bright, small, round." It is irregular in form, with a central spike.

<span class="mw-page-title-main">NGC 7130</span> Galaxy in the constellation Piscis Austrinus

NGC 7130 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 7130 is about 100,000 light years across. It was discovered by John Herschel on September 25, 1834, and discovered independently by Lewis Swift on September 17, 1897. The location of the galaxy given in the New General Catalogue was off by 30 arcminutes in declination from the location of the galaxy.

<span class="mw-page-title-main">Antlia-Sextans Group</span> Galaxy group in the constellations of Hydra, Sextans, Antlia and Leo

The Antlia-Sextans Group is a small Galaxy group in the constellations Hydra, Sextans, Antlia and Leo. It is, on average, approximately 4.3 million light-years away from the Milky Way. It is generally considered to be at the very edge of the Local Group and thus part of it. However, other researchers indicate it is an independent Galaxy group, unlikely to be gravitationally bound to the Local Group due to probably lying outside the Local Group's Zero-velocity surface, and thus the nearest Galaxy group to the Local Group rather than a subgroup within the Local Group. Nonetheless—this possible independence may disappear as the Milky Way continues coalescing with Andromeda due to the increased mass, and density thereof, plausibly widening the radius of the Zero-velocity surface of the Local Group.

<span class="mw-page-title-main">NGC 4393</span> Galaxy in the constellation of Coma Berenices

NGC 4393 is a spiral galaxy about 46 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 11, 1785. It is a member of the NGC 4274 Group, which is part of the Coma I Group or Cloud.

References

  1. 1 2 3 4 5 6 7 "NASA/IPAC Extragalactic Database". Results for IC 10. Retrieved 15 March 2007.
  2. ↑ "NED Query Results for IC 0010". ned.ipac.caltech.edu. Retrieved 8 August 2021.
  3. ↑ "IC 10". Star-Watcher.
  4. ↑ "APOD: 2012 January 4 – Starburst Galaxy IC 10". apod.nasa.gov. Retrieved 8 August 2021.
  5. 1 2 "IC 10". SEDS Messier Database. Retrieved 15 May 2006.
  6. ↑ "NED Query Results for IC 0010". ned.ipac.caltech.edu. Retrieved 8 August 2021.
  7. 1 2 3 4 Van den Bergh, Sidney (2000). Galaxies of the Local Group (1st ed.). Cambridge University Press. ISBN   0-521-65181-6.
  8. ↑ "APOD: 2012 January 4 – Starburst Galaxy IC 10". apod.nasa.gov. Retrieved 8 August 2021.
  9. ↑ Cosens, Maren; Wright, Shelley A.; Murray, Norman; Armus, Lee; Sandstrom, Karin; Do, Tuan; Larson, Kirsten; Martinez, Gregory; Sabhlok, Sanchit; Vayner, Andrey; Wiley, James (2022). "Kinematics and Feedback in H II Regions in the Dwarf Starburst Galaxy IC 10". The Astrophysical Journal. 929 (1): 74. arXiv: 2202.04098 . Bibcode:2022ApJ...929...74C. doi: 10.3847/1538-4357/ac52f3 . S2CID   246679827.
  10. ↑ Bolatto, A. D.; Jackson, J. M.; Wilson, C. D.; Moriarty-Schieven, G. (2000). "Submillimeter Observations of IC 10: The Dust Properties and Neutral Carbon Content of a Low-Metallicity Starburst". Astrophysical Journal. 532 (2): 909–921. arXiv: astro-ph/9910564 . Bibcode:2000ApJ...532..909B. doi:10.1086/308590. S2CID   15330330.
  11. ↑ van den Bergh, Sidney (April 2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific. 112 (770): 529–536. arXiv: astro-ph/0001040 . Bibcode:2000PASP..112..529V. doi:10.1086/316548. S2CID   1805423.
  12. ↑ Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W. (October 1997). "A Search for 'Dwarf' Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". Astrophysical Journal Supplement. 112 (2): 315–390. arXiv: astro-ph/9704107 . Bibcode:1997ApJS..112..315H. doi:10.1086/313041. S2CID   17086638.
  13. ↑ "Spiral, elliptical, irregular". www.spacetelescope.org. Retrieved 17 June 2019.


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