UGC 9128

UGC 9128
UGC 9128
Observation data (J2000 epoch)
Constellation	Boötes
Right ascension	14^h 15^m 56.70^s[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)×10^7 [3] M☉
Size	3300 ly[5]
Other designations
UGC 9128, DDO 187,[6] PGC 50961

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 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]

References

1. Cotton, W. D.; Condon, J. J.; Arbizzani, E. (1999). "Arcsecond Positions of UGC Galaxies". The Astrophysical Journal Supplement Series. 125 (2): 409–412. Bibcode:1999ApJS..125..409C. doi:10.1086/313286. S2CID 122517686.
2. "Dwarf galaxy: small but perfectly formed". www.spacetelescope.org. Retrieved 8 August 2021.
3. "Dynamics of starbursting dwarf galaxies" (PDF). Retrieved 8 August 2021.
4. McConnachie, Alan W. (2012-06-05). "The Observed Properties of Dwarf Galaxies in and Around the Local Group". The Astronomical Journal. 144 (1): 4. arXiv:1204.1562. Bibcode:2012AJ....144....4M. doi:10.1088/0004-6256/144/1/4. ISSN 0004-6256. S2CID 118515618.
5. Plait, Phil (25 April 2011). "And the cottonball galaxies shall inherit the Universe". Slate Magazine. Retrieved 8 August 2021.
6. Aparicio, Antonio; Tikhonov, Nikolay; Karachentsev, Igor (2000). "DDO 187: Do Dwarf Galaxies Have Extended, Old Halos?". The Astronomical Journal. 119 (1): 177–187. arXiv:astro-ph/9909493. Bibcode:2000AJ....119..177A. doi:10.1086/301157.