UGC 9128

UGC 9128 is a dwarf irregular galaxy around 6.8–7.8 Mly (2.1–2.4 Mpc) away; it is thought to be in the Local Group, although its membership is not certain.^[2][3] The galaxy has a mass of about (1.3±0.2)×10⁷ M_☉, around 100 million stars, and a diameter of around 3300 ly.^[3][5] It is therefore quite faint, and so was only discovered in the 20th century.^[2]

UGC 9128
UGC 9128 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Boötes
Right ascension	14h 15m 56.70s[1]
Declination	23° 03′ 16.2″[1]
Distance	6.8–7.8 Mly (2.1–2.4 Mpc)[2][3]
Characteristics
Type	dIrr[4]
Mass	(1.3±0.2)×107 [3] M☉
Size	3300 ly[5]
Other designations
UGC 9128, DDO 187,[6] PGC 50961

UGC 9128 is around 2.7 Mly from GR 8, which is its nearest neighbour.^[6]

UGC 9128 is a starburst galaxy, with the peak of star formation being 20–100 million years ago.^[3][6] It is thought to have both a halo and disc.^[6]