Holmberg IX

Holmberg IX is a dwarf irregular galaxy and a satellite galaxy of M81, located in the constellation of Ursa Major. It is a Magellanic type galaxy, similar to the Small Magellanic Cloud, neighbour galaxy to the Milky Way Galaxy.^[3] The galaxy is named after Erik Holmberg who first described it, though it was originally found by Sidney van den Bergh.^[3] Based on the observed age distribution of stars it contains, 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]

Holmberg IX
Hubble Space Telescope image of the dwarf irregular galaxy Holmberg IX
Observation data (J2000 epoch)
Constellation	Ursa Major
Right ascension	09h 57m 32.1s[1]
Declination	+69° 02′ 46″[1]
Distance	12 Mly (3.6 Mpc)[2]
Apparent magnitude (V)	16.5[1]
Characteristics
Type	dI[1]
Apparent size (V)	1.41 ± 0.07[1]
Notable features	Satellite galaxy of Messier 81
Other designations
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