Andromeda I

Infobox Galaxy
name = Andromeda I


epoch = J2000
type = E3 pec?cite web
title=NASA/IPAC Extragalactic Database
work=Results for Andromeda I
url=http://nedwww.ipac.caltech.edu/
accessdate=2008-01-21 ]
ra = RA|00|45|39.8
dec = DEC|+38|02|28
dist_ly = 2.40 ± 0.08 Mly (735 ± 23 kpc)citation
author = I. D. Karachentsev, V. E. Karachentseva, W. K. Hutchmeier, D. I. Makarov
title = A Catalog of Neighboring Galaxies
journal = Astronomical Journal
year = 2004
volume = 127
pages = 2031–2068
url = http://adsabs.harvard.edu/abs/2004AJ....127.2031K
doi = 10.1086/382905] citation
author = Karachentsev, I. D.; Kashibadze, O. G.
title = Masses of the local group and of the M81 group estimated from distortions in the local velocity field
journal = Astrophysics
year = 2006
volume = 49
issue = 1
pages = 3–18
url = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap.....49....3K
doi = 10.1007/s10511-006-0002-6]
z = -368 ± 11 km/s
appmag_v = 13.6
size_v = 2′.5 × 2′.5
constellation name = Andromeda
notes = satellite galaxy of M31
names = And I, Anon 0043+37, PGC 2666

Andromeda I is a dwarf spheroidal galaxy(dSph)citation
last1 = van den Bergh
first1 = Sydney
authorlink1 = Sidney van den Bergh
journal = Astrophysical Journal
year = 1972
date = January 1972
title = Search for Faint Companions to M31
volume = 171
url = http://adsabs.harvard.edu/abs/1972ApJ...171L..31V
pages = L31
doi = 10.1086/180861] about 2.40 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.citation
publisher = Students for the Exploration and Development of Space (SEDS)
title = Andromeda I
year = 2001
date = July 25 2001
url = http://www.seds.org/~spider/spider/LG/and1.html] As of 2005, it is the closest known dSph companion to M31citation
url = http://adsabs.harvard.edu/abs/2005AJ....129.2232P
title = The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda I and Andromeda III
authors = Pritzl, Barton J.; Armandroff, Taft E.; Jacoby, George H.; Da Costa, G. S.
year = 2005
date = May 2005
journal = The Astronomical Journal
volume = 129
issue = 5
pages = 2232–2256
doi = 10.1086/428372] at an estimated projected distance of ~40citation
url = http://adsabs.harvard.edu/abs/2004MNRAS.350..243M
title = Determining the location of the tip of the red giant branch in old stellar populations: M33, Andromeda I and II
authors = McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N.
year = 2004
date = May 2004
journal = Monthly Notices of the Royal Astronomical Society
volume = 350
issue = 1
pages = 250
doi = 10.1111/j.1365-2966.2004.07637.x] kpc.

Andromeda I was discovered by Sidney van den Berghcite journal
author=McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N.
title=Distances and metallicities for 17 Local Group galaxies
journal=Monthly Notices of the Royal Astronomical Society
year=2005
volume=356
issue=4
pages=979–997
url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005MNRAS.356..979M | doi=10.1111/j.1365-2966.2004.08514.x] in 1970 with the Mount Palomar Observatory 48-inch telescope. Further study of Andromeda I was done by the WFPC2 camera of the Hubble Space Telescope. This found that the horizontal branch stars, like other dwarf spheroidal galaxies were predominantly red.citation
authors = Da Costa, G. S.; Armandroff, T. E.; Caldwell, Nelson; Seitzer, Patrick
title = The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I
year = 1996
date = December 1996
url = http://adsabs.harvard.edu/abs/1996AJ....112.2576D
journal = Astronomical Journal
volume = 112
pages = 2576
doi = 10.1086/118204] From this, and the abundance of blue horizontal branch stars, along with 99 RR Lyrae stars detected in 2005, 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 Andromeda I, being the least luminous galaxy where such a cluster was found.citation
authors = Grebel, E. K.; Dolphin, A. E.; Guhathakurta, P.
title = Discovery of a Globular Cluster in M31's Dwarf Spheroidal Companion Andromeda I
year = 2000
url = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?2000AGM....17..P61G
journal = Astronomische Gesellschaft Abstract Series
chapter = Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft
place = Bremen
date = September 18-23, 2000
volume = 17
issue =
pages = ]

ee also

* Andromeda's satellite galaxies

External links

*

References