Leo V dwarf galaxy

from Wikipedia, the free encyclopedia
Galaxy
Leo V dwarf galaxy
{{{Card text}}}
Photo-request.svg
AladinLite
Constellation lion
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 11 h 31 m 9.6 s
declination + 02 ° 13 ′ 12 ″
Appearance
Morphological type dSph  
Brightness  (visual) (16.0 ± 0.4) mag
Angular expansion (5.2 ± 1.2) ′
Physical data
Affiliation Local group  
distance 585,000
(570,000 ± 30,000) ly /
180,000
(175,000 ± 9,000) pc
Absolute brightness (−5.2 ± 0.4) mag
history
Discovery date 2007
Catalog names
Leo V

The Leo V dwarf galaxy , also known as Leo V for short , is a spheroidal dwarf galaxy (dSph) in the constellation of Leo . It was discovered in 2007 based on data from the Sloan Digital Sky Survey . The galaxy lies at a distance of about 180 k pc and is moving away from our sun at a speed of about 173 km / s . It is almost spherical in shape and has a half-light radius of approximately 130 pc.

properties

Leo V is one of the smallest and faintest satellites of the Milky Way . The integral luminosity of the galaxy is about 10,000 times that of the sun and in absolute brightness is M V = (−5.2 ± 0.4) mag (other sources also mention the value −4.3 mag and one here smaller half-light radius of 40 pc, which would be less than that of a typical globular cluster ).

Even so, the mass of Leo V is 330,000 solar masses , which results in a mass-to-luminosity ratio of 75. This relatively high value implies a dominance by dark matter for this galaxy. The star population of the dwarf galaxy consists mainly of ancient stars that formed more than 12 billion years ago. The metallicity of the galaxy is correspondingly low with [Fe / H] ≈ −2.0 ± 0.2, ie it has about a hundredth of heavy elements compared to the sun .

Leo V is only about 3 degrees away from another satellite galaxy Leo IV in our Milky Way. The latter is still 20 kpc closer to the sun. There is evidence that the two galaxies are physically coupled, and evidence of a connection through stellar currents , a star bridge.

Individual evidence

  1. ↑ a b SIMBAD Astronomical Database . In: Results for Leo V Dwarf Spheroidal . Retrieved February 4, 2010.
  2. ↑ a b c d e f g V. Belokurov, Walker, MG; Evans, NW et al. : Leo V: A companion of a companion of the Milky Way galaxy . In: The Astrophysical Journal . 686, No. 2, 2008, pp. L83-L86. arxiv : 0807.2831 . bibcode : 2008ApJ ... 686L..83B . doi : 10.1086 / 592962 .
  3. ↑ a b c d e f De Jong, JTA; Martin, NF; Rix, HW; Smith, KW; Jin, S .; MacCiò, AV: The Enigmatic Pair of Dwarf Galaxies Leo IV and Leo V: Coincidence or Common Origin? . In: The Astrophysical Journal . 710, No. 2, 2010, p. 1664. doi : 10.1088 / 0004-637X / 710/2/1664 .
  4. ↑ a b M. G. Walker, Belokurov, V .; Evans, NW et al. : Leo V: Spectroscopy of a Distant and Disturbed Satellite . In: The Astrophysical Journal . 694, No. 2, 2009, pp. L144-147. arxiv : 0902.3003 . bibcode : 2009ApJ ... 694L.144W . doi : 10.1088 / 0004-637X / 694/2 / L144 .