Andromeda I

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Galaxy
Andromeda I
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Andromeda I as seen by the Hubble Space Telescope
Andromeda I as seen by the Hubble Space Telescope
AladinLite
Constellation Andromeda
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 00 h 45 m 39.8 s
declination + 38 ° 02 ′ 28 ″
Appearance
Morphological type E3 pec / dSph  
Brightness  (visual) 13.6 mag
Angular expansion 2 ′, 5 × 2 ′, 5
Physical data
Redshift −0.001228 ± 0.000037  
Radial velocity (−368 ± 11) km / s  
distance (2,400,000 ± 80,000) ly /
(735,000 ± 23,000) pc
history
discovery Sidney van den Bergh
Discovery date 1970
Catalog names
PGC  2666 • And I, Anon 0043 + 37,

Andromeda I is a spheroidal dwarf galaxy (dSph) in the constellation of Andromeda . The galaxy is about 2.4 million light years from our solar system. Andromeda I is a member of the Local Group and is a satellite of the Andromeda Galaxy (M31).

properties

The dwarf galaxy is roughly 3.5 degrees south and slightly east of M31. As of 2005, it is the closest satellite galaxy to Andromeda with an estimated projected distance of around 40 k pc or 150,000 light years.

Andromeda I was discovered in 1970 by Sidney van den Bergh with the 1.2 m Oschin Schmidt telescope at the Palomar observatory . Further research on Andromeda I was carried out using the Wide Field / Planetary Camera 2 of the Hubble Space Telescope .

As with other spheroidal dwarf galaxies, these found a horizontal branch mainly dominated by red giants . This and the additional determination of the frequency of the blue stars on the horizontal branch as well as the discovery of 99 RR Lyrae stars in 2005 could show that Andromeda I lived through an extended era of star formation of around 10 billion years. The Hubble telescope also discovered a globular cluster as a companion to Andromeda I , which makes it the faintest galaxy with such a satellite.

additional

Individual evidence

  1. ↑ a b c d e f NASA / IPAC Extragalactic Database. In: Results for Andromeda I. Retrieved January 21, 2008 .
  2. ↑ a b I. D. Karachentsev, VE Karachentseva, WK Hutchmeier, DI Makarov: A Catalog of Neighboring Galaxies . In: Astronomical Journal . tape 127 , no. 4 , 2004, p. 2031-2068 , doi : 10.1086 / 382905 , bibcode : 2004AJ .... 127.2031K .
  3. ↑ ID Karachentsev, OG Kashibadze: Masses of the local group and of the M81 group estimated from distortions in the local velocity field . In: Astrophysics . tape 49 , no. 1 , 2006, p. 3–18 , doi : 10.1007 / s10511-006-0002-6 , bibcode : 2006Ap ..... 49 .... 3K .
  4. ↑ a b c A. W. McConnachie, MJ Irwin, AMN Ferguson, RA Ibata, GF Lewis, N. Tanvir: Determining the location of the tip of the red giant branch in old stellar populations: M33, Andromeda I and II . In: Monthly Notices of the Royal Astronomical Society . tape 350 , no. 1 , May 2004, p. 250 , doi : 10.1111 / j.1365-2966.2004.07637.x , arxiv : astro-ph / 0401453 , bibcode : 2004MNRAS.350..243M .
  5. ^ A b Sidney van den Bergh: Search for Faint Companions to M31 . In: Astrophysical Journal . tape 171 , January 1972, p. L31 , doi : 10.1086 / 180861 , bibcode : 1972ApJ ... 171L..31V .
  6. ↑ a b Andromeda I . In: Students for the Exploration and Development of Space (SEDS) . July 25, 2001 ( seds.org ).
  7. ↑ a b Barton J. Pritzl, Taft E. Armandroff, George H. Jacoby, GS Da Costa: The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda I and Andromeda III . In: The Astronomical Journal . tape 129 , no. 5 , May 2005, pp. 2232–2256 , doi : 10.1086 / 428372 , arxiv : astro-ph / 0501083 , bibcode : 2005AJ .... 129.2232P .
  8. ↑ AW McConnachie, MJ Irwin, AMN Ferguson, RA Ibata, GF Lewis, N. Tanvir: Distances and metallicities for 17 Local Group galaxies . In: Monthly Notices of the Royal Astronomical Society . tape 356 , no. 4 , 2005, p. 979–997 , doi : 10.1111 / j.1365-2966.2004.08514.x , arxiv : astro-ph / 0410489 , bibcode : 2005MNRAS.356..979M .
  9. ↑ GS Da Costa, TE Armandroff, Nelson Caldwell, Patrick Seitzer: The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I . In: Astronomical Journal . tape 112 , December 1996, p. 2576 , doi : 10.1086 / 118204 , arxiv : astro-ph / 9610083 , bibcode : 1996AJ .... 112.2576D .
  10. ↑ EK Grebel, AE Dolphin, P. Guhathakurta: Discovery of a Globular clusters in M31's Dwarf Spheroidal Companion Andromeda I . In: Astronomical Society Abstract Series . tape 17 , Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft, September 18, 2000, bibcode : 2000AGM .... 17..P61G .

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