Cassiopeia dwarf galaxy

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Galaxy
Cassiopeia dwarf galaxy
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Image of the Cassiopeia dwarf galaxy by HST / WikiSky
Image of the Cassiopeia dwarf galaxy by HST / WikiSky
AladinLite
Constellation Cassiopeia
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 23 h 26 m 31.0 s
declination 50 ° 41 ′ 31 ″
Appearance
Morphological type dSph  
Brightness  (visual) 12.9 mag
Angular expansion (2.5 × 2.0) ′
Physical data
Affiliation Local group  
Radial velocity (−307 ± 2) km / s  
distance (2,580,000 ± 130,000) Lj /
(790,000 ± 40,000) pc
history
discovery Karachentsev and Karachentseva
Discovery date 1998
Catalog names
PGC  2807155 • Andromeda VII, And VII, Cas dSph

The Cassiopeia dwarf galaxy or Andromeda VII is a spheroidal dwarf galaxy in the constellation of Cassiopeia and was discovered in 1998 together with Pegasus II by a Russian- Ukrainian team of astronomers (Karachentsev and Karachentseva).

The dwarf galaxy is part of the local group and satellite galaxy of the Andromeda Galaxy ( M31 ). The galaxy is in a distance of about 790 k pc of our solar system and is approaching this with a speed of approximately 307 km / s .

The Cassiopeia dwarf galaxy (as well as Pegasus II) are further away from M31 than their previously known satellites, but seem to be gravitationally bound to them. The galaxy shows just as little evidence of young, massive stars as it does of recent star formation . The star population is dominated by a very old star population up to 10 billion years old.

additional

Individual evidence

  1. ↑ SIMBAD Astronomical Database. Retrieved November 21, 2011 .
  2. ↑ a b c d e NED
  3. ↑ ID Karachentsev, VE Karachentseva, WK Hutch Meier, 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 .
  4. ↑ ID Karachentsev, VE Karachentseva: New probable companions to M31 found on the POSS-II . In: Astronomy and Astrophysics . tape 341 , no. 1 , 1999, p. 355–356 , bibcode : 1999A & A ... 341..355K .
  5. ^ Results for Andromeda VII. In: SIMBAD Astronomical Database. Center de Données astronomiques de Strasbourg, accessed March 6, 2010 .
  6. ↑ 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 .

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