Omicron Leonis

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Template:Short description

Omicron Leonis
File:Leo constellation map.png
Omicron Leonis is located to the lower far right on this map of the constellation.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Leo
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +3.52[2]
Characteristics
Spectral type F8-G0III + A7m[3]
U−B Template:Engvar 0.21[2]
B−V Template:Engvar 0.49[2]
Astrometry
Proper motion (μ) RA: -143.20[4] mas/yr
Dec.: -37.20[4] mas/yr
Parallax (π)24.412±0.081 mas[5]
DistanceTemplate:Val ly
(Template:Val pc)[5]
Absolute magnitude (MV)+0.51[6]
Orbit[5]
PrimaryAa
CompanionAb
Period (P)Template:Val days
Semi-major axis (a)Template:Val
Eccentricity (e)Template:Val
Inclination (i)Template:Val°
Longitude of the node (Ω)Template:Val°
Periastron epoch (T)Template:Val days
Argument of periastron (ω)
(secondary)
Template:Val°
Semi-amplitude (K1)
(primary)
Template:Val km/s
Semi-amplitude (K2)
(secondary)
Template:Val km/s
Details[5]
ο Leo Aa
MassTemplate:Val Template:Solar mass
RadiusTemplate:Val Template:Solar radius
LuminosityTemplate:Val Template:Solar luminosity
TemperatureTemplate:Val K
Metallicity [Fe/H]Template:Val dex
AgeTemplate:Val Gyr
ο Leo Ab
MassTemplate:Val Template:Solar mass
RadiusTemplate:Val Template:Solar radius
LuminosityTemplate:Val Template:Solar luminosity
TemperatureTemplate:Val K
Metallicity [Fe/H]Template:Val dex
AgeTemplate:Val Gyr
Other designations
Subra, ο Leo, 14 Leo, BD+10 2044, FK5 365, HD 83808/83809, HIP 47508, HR 3852, SAO 98709
Database references
SIMBADdata

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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. The position of this system near the ecliptic means it is subject to lunar occultation.[7]

It consists of a binary pair, designated Omicron Leonis A and an optical companion, Omicron Leonis B.[8] A's two components are themselves designated Omicron Leonis Aa (officially named Subra Template:IPAc-en, the traditional name for the system)[9][10] 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).[11]

It bore the traditional name Subra, from the Arabic زبرة zubra (upper part of the back), originally applied to Delta and Theta Leonis.[12]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[13] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[14] 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.[10]

In Chinese astronomy, this star is named Taimin (太民); it and ρ Leonis (Shaomin, 少民) were the two southernmost stars of the Xuanyuan (轩辕) constellation.[15]

Properties

The two members of the spectroscopic pair have similar brightnesses, but are very different stars: the primary is given the type F8-G0III giant; and the secondary is a type A7m dwarf.[16] 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.[8] It is an 11th-magnitude star a little more massive and hotter than the Sun, but much further away than the spectroscopic pair.[17]

References

Template:Reflist

External links

Template:Stars of Leo

  1. a b Template:Cite Gaia DR3
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  8. a b Script error: No such module "citation/CS1".
  9. Script error: No such module "citation/CS1".
  10. a b Script error: No such module "citation/CS1".
  11. Script error: No such module "citation/CS1".
  12. Jim Kaler's website: http://stars.astro.illinois.edu/sow/subra.html (online 6th Sep 2015)
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  17. Template:Cite Gaia DR3