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Andromeda I is a dwarf spheroidal galaxy about 3 million light-years away in the constellation Andromeda. Andromeda I is part of the Local group of galaxies and a satellite galaxy of the Andromeda Galaxy (M31). It is roughly 3.5 degrees south and slightly east of M31.
And 1 was discovered by Sydney van Der Bergh in 1970 with the Mount Palomar Observatory 48-inch telescope. Further study of And 1 was done by the WFPC2 camera of the Hubble Space Telescope. This found that the horizontal branch stars, like other dSph galaxies were predominantly red. From this, and the abundance of blue horizontal branch stars, along with RR Lyrae stars, lead to the conclusion there was an extended epoch of star formation. The estimated age is approximately 10 Gyr. The Hubble telescope also found a globular cluster in And 1, being the least luminous galaxy where such a cluster was found.
See also
References
- Grebel, E. K.; Dolphin, A. E.; Guhathakurta, P. Discovery of a Globular Cluster in M31's Dwarf Spheroidal Companion Andromeda I (2000) The Publications of the Astronomical Society of the Pacific, Volume 112, Issue 770, pp. 529-536.
- Da Costa, G. S.; Armandroff, T. E.; Caldwell, Nelson; Seitzer, Patrick. The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I (1996) Astronomical Journal v.112, p.2576
- van den Bergh, Sidney. Search for Faint Companions to M31 (1972). Astrophysical Journal, vol. 171, p. L31-L33
- van den Bergh, Sidney. Updated Information on the Local Group. (2000) PASP, Vol. 112, No. 770, p. 529-536
Andromeda Subgroup | Dwarf spheroidal galaxies | Andromeda constellation
"Andromeda I"