# Sextans B

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Dwarf irregular galaxy in the constellation Sextans

Sextans B Sextans B, imaged by the 4-meter Telescope at Kitt Peak National Observatory Observation data (J2000 epoch) Constellation Sextans Right ascension 10h 00m 00.1s[1] Declination +05° 19′ 56″[1] Redshift 301 ± 1 km/s[1] Distance 4.44 ± 0.23 Mly (1.36 ± 0.07 Mpc)[2][3] Apparent magnitude (V) 11.9[1] Characteristics Type ImIV–V[1] Size ~8,900 ly (2.73 kpc) (estimated)[1] Apparent size (V) 5.1′ × 3.5′[1] Other designations DDO 70, UGC 5373, MCG +01-26-005, PGC 28913, CGCG 036-012

**Sextans B** (also known as **UGC 5373** and **DDO 70**) is an [irregular](/source/Irregular_galaxy) [galaxy](/source/Galaxy) that may be part of the [Local Group](/source/Local_Group), or lie just beyond it. The earliest known reference to this galaxy is from a 1954 paper by [Edison Pettit](/source/Edison_Pettit) in [The Astrophysical Journal](/source/The_Astrophysical_Journal), where it was listed as "Wilson Dwarf".[4]

Sextans B is 4.44 million [light-years](/source/Light-year) away from [Earth](/source/Earth) and thus is one of the most distant members of the Local Group, if it is indeed a member. It forms a pair with its neighbouring galaxy [Sextans A](/source/Sextans_A).[5] It is a type Ir IV–V galaxy according to the [galaxy morphological classification](/source/Galaxy_morphological_classification) scheme.[6] Sextans B may also be gravitationally associated with the galaxies [NGC 3109](/source/NGC_3109) and the [Antlia Dwarf](/source/Antlia_Dwarf).[7]

Sextans B has a uniform stellar population,[8] but the interstellar medium in it may be inhomogeneous.[9] Its mass is estimated to be about 2×108 times the mass of the [Sun](/source/Sun), of which 5.5×107 is in the form of atomic [hydrogen](/source/Hydrogen).[8] Star formation in the galaxy seems to have proceeded in distinct periods of low intensity, separated by shorter periods of no activity.[8] The existence of [Cepheid variables](/source/Cepheid_variable) in the galaxy implies that Sextans B contains at least some young stars.[6] The [metallicity](/source/Metallicity) of Sextans B is very low, with a value of approximately Z = 0.001.[8] Sextans B is receding from the [Milky Way](/source/Milky_Way) with a speed of approximately 300 kilometres per second (190 mi/s),[9] and probably lies just outside the edge of the [Local Group](/source/Local_Group), so as its neighbour [Sextans A](/source/Sextans_A).[10]

Five [planetary nebulae](/source/Planetary_nebula) have been identified in Sextans B, which is one of the smallest galaxies where planetary nebulae have been observed. These appear point-like and can be identified by their spectral emission lines.[11] It also contains a massive [globular cluster](/source/Globular_cluster).[12]

Although no [supernovae](/source/Supernova) have been observed in Sextans B, the galaxy is close enough for classical [novae](/source/Nova) to be detected. The first confirmed nova in this galaxy was discovered by [ATLAS](/source/Asteroid_Terrestrial-impact_Last_Alert_System) at magnitude 18.553 on 10 November 2024, and designated AT 2024aawe.[13]

## References

1. ^ [***a***](#cite_ref-ned_1-0) [***b***](#cite_ref-ned_1-1) [***c***](#cite_ref-ned_1-2) [***d***](#cite_ref-ned_1-3) [***e***](#cite_ref-ned_1-4) [***f***](#cite_ref-ned_1-5) [***g***](#cite_ref-ned_1-6) ["NASA/IPAC Extragalactic Database"](http://nedwww.ipac.caltech.edu/). *Results for Sex B*. Retrieved 2006-12-13.

1. **[^](#cite_ref-karachentsevetal2004_2-0)** I. D. Karachentsev; V. E. Karachentseva; W. K. Hutchmeier; D. I. Makarov (2004). ["A Catalog of Neighboring Galaxies"](https://doi.org/10.1086%2F382905). *Astronomical Journal*. **127** (4): 2031–2068. [Bibcode](/source/Bibcode_(identifier)):[2004AJ....127.2031K](https://ui.adsabs.harvard.edu/abs/2004AJ....127.2031K). [doi](/source/Doi_(identifier)):[10.1086/382905](https://doi.org/10.1086%2F382905).

1. **[^](#cite_ref-Karachentsevetal2006_3-0)** Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". *Astrophysics*. **49** (1): 3–18. [Bibcode](/source/Bibcode_(identifier)):[2006Ap.....49....3K](https://ui.adsabs.harvard.edu/abs/2006Ap.....49....3K). [doi](/source/Doi_(identifier)):[10.1007/s10511-006-0002-6](https://doi.org/10.1007%2Fs10511-006-0002-6). [S2CID](/source/S2CID_(identifier)) [120973010](https://api.semanticscholar.org/CorpusID:120973010).

1. **[^](#cite_ref-4)** Pettit, Edison (1954). "Magnitudes and Color Indices of Extragalactic Nebulae Determined Photoelectrically". *The Astrophysical Journal*. **120**: 413. [Bibcode](/source/Bibcode_(identifier)):[1954ApJ...120..413P](https://ui.adsabs.harvard.edu/abs/1954ApJ...120..413P). [doi](/source/Doi_(identifier)):[10.1086/145932](https://doi.org/10.1086%2F145932).

1. **[^](#cite_ref-SandageCarlson1985_5-0)** Sandage, Allan; Carlson, George (July 1985). ["The brightest stars in nearby galaxies. V – Cepheids and the brightest stars in the dwarf galaxy Sextans B compared with those in Sextans A"](https://doi.org/10.1086%2F113809). *[Astronomical Journal](/source/Astronomical_Journal)*. **90**: 1019–1026. [Bibcode](/source/Bibcode_(identifier)):[1985AJ.....90.1019S](https://ui.adsabs.harvard.edu/abs/1985AJ.....90.1019S). [doi](/source/Doi_(identifier)):[10.1086/113809](https://doi.org/10.1086%2F113809).

1. ^ [***a***](#cite_ref-vandenBergh2000_6-0) [***b***](#cite_ref-vandenBergh2000_6-1) van den bergh, Sidney (2000). [*The galaxies of the Local Group*](https://books.google.com/books?id=NfOwG3cyAGIC&pg=PA265). [University of Cambridge](/source/University_of_Cambridge). p. 265. [ISBN](/source/ISBN_(identifier)) [978-0-521-65181-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-521-65181-3).

1. **[^](#cite_ref-vandenbergh1999_7-0)** van den Bergh, Sidney (1999). "Stellar Content of Local Group Galaxies – An Introduction". *The Stellar Content of Local Group Galaxies*. **192**: 3. [Bibcode](/source/Bibcode_(identifier)):[1999IAUS..192....3V](https://ui.adsabs.harvard.edu/abs/1999IAUS..192....3V).

1. ^ [***a***](#cite_ref-TosiEtAl1991_8-0) [***b***](#cite_ref-TosiEtAl1991_8-1) [***c***](#cite_ref-TosiEtAl1991_8-2) [***d***](#cite_ref-TosiEtAl1991_8-3) Tosi, M; Greggio, L.; Marconi, G.; Focardi, P. (September 1991). "Star formation in dwarf irregular galaxies – Sextans B". *[Astronomical Journal](/source/Astronomical_Journal)*. **102**: 951–974. [Bibcode](/source/Bibcode_(identifier)):[1991AJ....102..951T](https://ui.adsabs.harvard.edu/abs/1991AJ....102..951T). [doi](/source/Doi_(identifier)):[10.1086/115925](https://doi.org/10.1086%2F115925).

1. ^ [***a***](#cite_ref-KniazevEtAl2005_9-0) [***b***](#cite_ref-KniazevEtAl2005_9-1) Kniazev, Alexei Y.; Grebel, Eva K.; Pustilnik, Simon A.; Pramskij, Alexander G.; Zucker, Daniel B. (October 2005). "Spectrophotometry of Sextans A and B: Chemical Abundances of H II Regions and Planetary Nebulae". *[Astronomical Journal](/source/Astronomical_Journal)*. **130** (4): 1558–1573. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0502562](https://arxiv.org/abs/astro-ph/0502562). [Bibcode](/source/Bibcode_(identifier)):[2005AJ....130.1558K](https://ui.adsabs.harvard.edu/abs/2005AJ....130.1558K). [doi](/source/Doi_(identifier)):[10.1086/432931](https://doi.org/10.1086%2F432931). [S2CID](/source/S2CID_(identifier)) [14176608](https://api.semanticscholar.org/CorpusID:14176608).

1. **[^](#cite_ref-AlloinGieren_10-0)** Alloin, Danielle M.; Gieren, Wolfgang (2000). [*Stellar candles for the extragalactic distance scale*](https://books.google.com/books?id=rpR1xfK3yFoC&pg=PA265). University of Cambridge. p. 265. [ISBN](/source/ISBN_(identifier)) [978-3-540-20128-1](https://en.wikipedia.org/wiki/Special:BookSources/978-3-540-20128-1).

1. **[^](#cite_ref-MagriniEtAl2002_11-0)** Magrini, L.; Corradi, R. L. M.; Walton, N. A.; Zijlstra, A. A.; Pollacco, D. L.; Walsh, J. R.; Perinotto, M.; Lennon, D. J.; Greimel, R. (2002). "The Local Group Census: Planetary nebulae in Sextans B". *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **386** (3): 869–873. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0202516](https://arxiv.org/abs/astro-ph/0202516). [Bibcode](/source/Bibcode_(identifier)):[2002A&A...386..869M](https://ui.adsabs.harvard.edu/abs/2002A&A...386..869M). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20020296](https://doi.org/10.1051%2F0004-6361%3A20020296). [S2CID](/source/S2CID_(identifier)) [16954005](https://api.semanticscholar.org/CorpusID:16954005).

1. **[^](#cite_ref-SharinaEtAl2007_12-0)** Sharina, M.E.; Puzia, T. H.; Krylatyh, A. S. (September 2009). "A globular cluster in the dwarf galaxy Sextans B". *[Astrophysical Bulletin](https://en.wikipedia.org/w/index.php?title=Astrophysical_Bulletin&action=edit&redlink=1)*. **62** (3): 209–216. [arXiv](/source/ArXiv_(identifier)):[0704.3908](https://arxiv.org/abs/0704.3908). [Bibcode](/source/Bibcode_(identifier)):[2007AstBu..62..209S](https://ui.adsabs.harvard.edu/abs/2007AstBu..62..209S). [doi](/source/Doi_(identifier)):[10.1134/S1990341307030029](https://doi.org/10.1134%2FS1990341307030029). [S2CID](/source/S2CID_(identifier)) [119588326](https://api.semanticscholar.org/CorpusID:119588326).

1. **[^](#cite_ref-13)** ["AT 2024aawe"](https://www.wis-tns.org/object/2024aawe). *Transient Name Server*. [IAU](/source/International_Astronomical_Union). Retrieved 12 November 2024.

## External links

Wikimedia Commons has media related to [Sextans B](https://commons.wikimedia.org/wiki/Category:Sextans_B).

- Sextans B on [WikiSky](/source/WikiSky): [DSS2](http://www.wikisky.org/?object=Sextans+B&img_source=DSS2), [SDSS](http://www.wikisky.org/?object=Sextans+B&img_source=SDSS), [GALEX](http://www.wikisky.org/?object=Sextans+B&img_source=GALEX), [IRAS](http://www.wikisky.org/?object=Sextans+B&img_source=IRAS), [Hydrogen α](http://www.wikisky.org/?object=Sextans+B&img_source=HALPHA), [X-Ray](http://www.wikisky.org/?object=Sextans+B&img_source=RASS), [Astrophoto](http://www.wikisky.org/?object=Sextans+B&img_source=IMG_all), [Sky Map](http://www.wikisky.org/?object=Sextans+B), [Articles and images](http://www.wikisky.org/starview?object=Sextans+B)

v t e Constellation of Sextans COSMOS field List of stars in Sextans Sextans in Chinese astronomy Stars Bayer α β γ δ ε Flamsteed 7 18 19 23 24 25 35 41 Variable Y UY HR 3879 3915 4092 4233 HD 86081 (Bibhā) 92788 93396 Other BD−08°2823 Gliese 393 K2-239 LHS 292 PSR J0952−0607 TOI-561 WASP-43 (Gnomon) WASP-127 Exoplanets BD−08°2823 b c HD 86081 b (Santamasa) HD 92788 b KELT-11b TOI-561 b WASP-43b (Astrolábos) Galaxies NGC 2967 2974 2980 3007 3015 3018 3044 3110 3115 3156 3166 3169 3326 3341 3423 Other 3MM-1 AzTECC71 Baby Boom Galaxy CAPERS-LRD-z9 CID-42 CID-346 Cosmos Redshift 7 HD1 Infinity Galaxy J1000+0221 J1010+0612 J10405643–0103584 LAE J095950.99+021219.1 LBQS 1009−0252 MoM-z14 PG 1011−040 PG 1012+008 PGC 29820 PGC 3092152 PMN J0948+0022 REBELS-25 Sextans A Sextans B Sextans Dwarf Spheroidal Zhúlóng Galaxy clusters Abell 907 CL J1001+0220 Hyperion proto-supercluster Astronomical events AT 2018hyz SN 1000+0216 Category

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Adapted from the Wikipedia article [Sextans B](https://en.wikipedia.org/wiki/Sextans_B) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Sextans_B?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.