Andromeda VIII

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Galaxy
Andromeda VIII
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Constellation Andromeda
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 00 h 42 m 06.0 s
declination + 40 ° 37 ′ 00 ″
Appearance
Morphological type dSph pec  
Brightness  (visual) 9.1 mag
Angular expansion 45 ′ × 10 ′
Surface brightness 24 mag / arcmin²
Physical data
Radial velocity −500 km / s  
distance 2,700,000 ly /
830,000 pc
Absolute brightness −15.6 mag
diameter 35,000 × 8,000 ly
history
discovery Morrison et al.
Discovery date 2003
Catalog names
And VIII

Andromeda VIII also briefly And VIII is a spheroidal dwarf galaxy (dSph) in the constellation of Andromeda . The galaxy is about 2.7 million light years from our solar system. Andromeda VIII is a member of the Local Group and is a satellite of the Andromeda Galaxy M31.

properties

Discovered in August 2003, the galaxy Andromeda VIII remained undiscovered for a long time due to its highly diffuse nature. Ultimately, the redshift of some stars in the foreground of the Andromeda Galaxy revealed their existence, which differed markedly from those of M31.

The dwarf galaxy contains between five to twelve planetary nebulae and one to three globular clusters , as well as a non-negligible amount of neutral hydrogen gas of around 4 × 10 5 M ʘ .

Due to the large differences in radial velocity with both M31 and M32 , it is almost impossible that And VIII is physically associated with them, rather proves that this dwarf galaxy is a separate galaxy with low surface brightness. The extreme elongation of the dwarf galaxy is due to the tidal forces mediated by the Andromeda galaxy, which threaten to tear the dwarf apart. The tides even let a significant number of stars escape from Andromeda VIII and form a star stream along the orbit .

Until at least 2006, the actual status of And VIII as a galaxy was uncertain (Merrett et al. 2006).

additional

Individual evidence

  1. ↑ a b NASA / IPAC Extragalactic Database . In: Results for Andromeda VIII . Retrieved January 21, 2008.
  2. ↑ a b c d e f Heather L. Morrison, Paul Harding, Denise Hurley-Keller and George Jacoby: Andromeda VIII: A New Tidally Distorted Satellite of M31 . In: The Astrophysical Journal . 596, No. 2, 2003, pp. L183-L186. arxiv : astro-ph / 0309254 . doi : 10.1086 / 379625 .
  3. ↑ SIMBAD Astronomical Database . In: Results for And VIII . Retrieved November 29, 2006.
  4. ^ Helen Merrett et al .: A deep kinematic survey of planetary nebulae in the Andromeda galaxy using the Planetary Nebula Spectrograph . In: Monthly Notices of the Royal Astronomical Society . 369, No. 1, June 2006, pp. 120-142. arxiv : astro-ph / 0603125 . bibcode : 2006MNRAS.369..120M . doi : 10.1111 / j.1365-2966.2006.10268.x .

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