Omicron Leonis

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Omicron Leonis

Omicron Leonis is located to the lower far right on this map of the constellation.
Observation data
J2000.0
Constellation Leo
Right ascension 09h 41m 09.03s
Declination +09° 53' 32.30"
Apparent magnitude (V) +3.52[1]
Characteristics
Spectral type F8-G0III + A7m[2]
U−B color index 0.21[1]
B−V color index 0.49[1]
Distance
135 ly
(41.4±0.1[4] pc)
Absolute magnitude (MV)+0.51[5]
Myr
ο Leo Ab
Mass1.87±0.01 M☉
Radius2.2±0.3 R☉
Luminosity15.4±1.0 L☉
Temperature7,600±400 K
HR 3852, SAO
98709
Database references
SIMBADdata

Omicron Leonis (ο Leonis, abbreviated Omicron Leo, ο Leo) is a

multiple star system in the constellation of Leo, west of Regulus, some 130 light-years from the Sun
, where it marks one of the lion's forepaws.

It consists of a binary pair, designated Omicron Leonis A and an optical companion, Omicron Leonis B.[6] A's two components are themselves designated Omicron Leonis Aa (officially named Subra /ˈsuːbrə/, the traditional name for the system)[7][8] and Ab.

Nomenclature

ο Leonis (Latinised to Omicron Leonis) is the star's Bayer designation. The designations of the two constituents as Omicron Leonis A and B, and those of A's components—Omicron Leonis Aa and Ab—derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[9]

It bore the traditional name Subra, from the Arabic زبرة zubra (upper part of the back), originally applied to Delta and Theta Leonis.[10]

In 2016, the

multiple systems.[12] It approved the name Subra for the component Omicron Leonis Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[8]

Properties

The two members of the spectroscopic pair have similar brightnesses, but are very different stars: the primary is given the

dwarf.[4] Their combined apparent magnitude
is +3.52.

The visible companion, component B, is a much fainter star that has increased its separation from about an

arc-minute to one and a half arc-minutes in the 350 years since it was first measured.[6] It is an 11th-magnitude star a little more massive and hotter than the Sun, but much further away than the spectroscopic pair.[13]

References

  1. ^
    Bibcode:2002yCat.2237....0D
    .
  2. doi:10.1086/342942
    .
  3. ^
    S2CID 18759600
    .
  4. ^
    S2CID 120280239
    .
  5. S2CID 119257644
    .
  6. ^ a b "Washington Double Star Catalog". United States Naval Observatory. Archived from the original on 14 February 2011. Retrieved 2 January 2018.
  7. ISBN 978-1-931559-44-7
    .
  8. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  9. arXiv:1012.0707 [astro-ph.SR
    ].
  10. ^ Jim Kaler's website: http://stars.astro.illinois.edu/sow/subra.html (online 6th Sep 2015)
  11. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  12. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  13. S2CID 244398875
    . Gaia DR3 record for this source at VizieR.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Omicron_Leonis&oldid=1197410516"