Antlia B

Antila B
NGC 3109 (which Antila B is a satellite of) is located towards the far left
Observation data (J2000.0 epoch)
Constellation	Antila
Right ascension	09 48 56.1
Declination	-25 59 24
Group or cluster	NGC 3109 association
Characteristics
Type	Dwarf irregular
Other designations
Ant B

Antlia B (also known as Ant B) is a faint dwarf irregular satellite galaxy located around 72 kiloparsecs from NGC 3109, a small irregular galaxy located 4.3 million light years from Earth at the edge of the local group. ^[1] Antila B has a complex mixture of old red giant branch stars over 10 billion years old and young blue stars only a few hundred years old. Despite Antlia B being rich in gas, Antlia B shows no evidence of active star formation. ^[2]

Stellar population

The stellar population of Antlia B is composed of prominent old, metal-poor red giant branch stars with ages greater than 10 billion years and young blue stars somewhere between 200-400 million years old. ^[1] Despite Antlia B being rich in gas to form new stars, there seems to be no evidence for active star formation within Antlia B. ^[2]

Stellar history

The history of star formation in Antlia B shows that there was relatively constant stellar mass growth for the first ~10-11 billion years of its history and then almost no growth for the last ~2-3 billion years. ^[2]

Discovery

The discovery of Antila B was from the Dark Energy Camera survey (DES). ^[1]

References

1. Sand, D. J.; Spekkens, K.; Crnojević, D.; Hargis, J. R.; Willman, B.; Strader, J.; Grillmair, C. J. (2015). "Antlia B: A Faint Dwarf Galaxy Member of the NGC 3109 Association". The Astrophysical Journal. 812 (1): L13. arXiv: 1508.01800 . Bibcode:2015ApJ...812L..13S. doi:10.1088/2041-8205/812/1/L13.
2. Hargis, Jonathan R.; Albers, S.; Crnojević, D.; Sand, D. J.; Weisz, D. R.; Carlin, J. L.; Spekkens, K.; Willman, B.; Peter, A. H. G.; Grillmair, C. J.; Dolphin, A. E. (2019). "Hubble Space Telescope Imaging of Antlia B: Star Formation History and a New Tip of the Red Giant Branch Distance". arXiv: 1907.07185 [astro-ph.GA].