Holmberg IX explained

Holmberg IX
Credit:	NASA, ESA, and the Hubble Heritage Team
Epoch:	J2000
Ra:	^[1]
Constellation Name:	Ursa Major
Dist Ly:	12 Mly (3.6 Mpc)^[2]
Type:	dI
Appmag V:	16.5
Size V:	1.41 ± 0.07
Notes:	Satellite galaxy of Messier 81
Names:	UGC 5336, [B93] 17, DDO 66, 2E 0953.7+6918, 2E 2199, 1ES 0953+69.3, HIJASS J0957+69A, Holmberg IX, [IW2001] H42, [IW2001] P63, K68 62, LEDA 28757, Mailyan 48, MCG+12-10-012, [MI94] Im 62, SPB 118, PGC 28757

Holmberg IX is a dwarf irregular galaxy and a satellite galaxy of M81, located in the constellation of Ursa Major. It is of the Magellanic type of Galaxy as it is similar to the Small Magellanic Cloud, neighbour galaxy to Milky Way Galaxy.^[3] The galaxy is named after Erik Holmberg who first described it though it was first found by Sidney van den Bergh.^[3] Based on the observed age distribution of stars it contains, a whole 20% of its stellar mass formed within the last 200 Myr, making it the youngest nearby galaxy.^[4] It is also home to one of two yellow supergiant eclipsing binary systems.^{[5] [6]}

Further reading

• Elemental Abundances of Nearby Galaxies through High Signal-to-Noise Ratio XMM-Newton Observations of Ultraluminous X-Ray Sources . Winter . Lisa M. . Mushotzky . Richard F. . Reynolds . Christopher S. . . 655 . 1 . 163–178 . 2007ApJ...655..163W . 10.1086/510200 . 2007. astro-ph/0610369 . 115819754 .
• The Ultraluminous X-ray Source in Holmberg IX and its Environment . Fabien . Grisé . Pakull . Manfred W. . Motch . Christian . 2006-05-12 . Proceedings of the International Astronomical Union . 1 . S230 . 302–303 . astro-ph/0603768 . 10.1017/S1743921306008519. 2006IAUS..230..302G . 118995588 .
• Tidal dwarfs in the M81 group: the second generation? . L. . Makarova . 2002 . . 396 . 2 . 473–487 . astro-ph/0210235 . 10.1051/0004-6361:20021426 . Grebel . E. K. . Karachentsev . I. D. . Dolphin . A. E. . Karachentseva . V. E. . Sharina . M. E. . Geisler . D. . Guhathakurta . P. . Hodge . P. W. . Sarajedini . A. . Seitzer . P. . 2002A&A...396..473M. 8 .
• The Dwarf Irregular Galaxy Holmberg IX . R. E. . Schulte-Ladbeck . Hopp . U. . 1987 . Mitteilungen der Astronomischen Gesellschaft . 70 . 1987MitAG..70..427S . 427 .
• Two Faint Companions to M81 . F. . Bertola . Maffei . P. . 1974 . . 32 . 1974A&A....32..117B . 117 .
• A study of physical groups of galaxies . E. . Holmberg . 1969 . Arkiv för Astronomi . 5 . 305–343 . 1969ArA.....5..305H.
• A catalogue of dwarf galaxies . van den Bergh . Sidney . 1959 . Publications of the David Dunlap Observatory . . 2 . 5 . 1959PDDO....2..147V . 147.

External links

• • M81's satellite galaxy Holmberg IX
• Holmberg IX: XMM1
• GALEX Completes Four Star-Studded Years in Space
• Dwarf Galaxy Holmberg IX

Notes and References

1. UGC 5336 .
2. LBT Discovery of a Yellow Supergiant Eclipsing Binary in the Dwarf Galaxy Holmberg IX . January 2008 . Prieto . J. L. . etal . . 673 . 1 . L59–L62 . 0709.2376 . 10.1086/527415 . 2008ApJ...673L..59P. 118735678 .
3. News: Holmberg IX news from Hubblesite. 8 January 2008. Hubblesite.
4. Holmberg IX: The Nearest Young Galaxy . E. . Sabbi . Gallagher . J. S. . Smith . L. J. . de Mello . D. F. . Mountain . M. . March 2006 . . 676 . 2 . L113–L117 . 0802.4446 . 10.1086/587548 . 2008ApJ...676L.113S. 119205873 .
5. News: Two new Star Systems are the First of Their kind Ever Found . dead . https://web.archive.org/web/20080402133205/http://researchnews.osu.edu/archive/superyellow.htm . 2008-04-02 .
6. News: Two Yellow Supergiant Eclipsing Binary Systems Discovered: First Of Their Kind Ever Found . 2008-04-01 . .