Astronomy:Omicron Leonis
250px Omicron Leonis is located to the lower far right on this map of the constellation. | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Leo |
| Right ascension | 09h 41m 09.032s[1] |
| Declination | +09° 53′ 32.31″[1] |
| Apparent magnitude (V) | +3.52[2] |
| Characteristics | |
| Spectral type | F8-G0III + A7m[3] |
| U−B color index | 0.21[2] |
| B−V color index | 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[5] mas |
| Distance | 133.53±0.45 ly (40.96±0.14 pc) |
| Absolute magnitude (MV) | +0.51[6] |
| Orbit[5] | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 14.498068(6) days |
| Semi-major axis (a) | 0.1834±0.0007 astronomical unit|AU |
| Eccentricity (e) | 0.0007±0.0004 |
| Inclination (i) | 57.8±0.2° |
| Longitude of the node (Ω) | 191.6±0.1° |
| Periastron epoch (T) | 2450623.9(9) days |
| Argument of periastron (ω) (secondary) | 214±22° |
| Semi-amplitude (K1) (primary) | 54.75±0.02 km/s |
| Semi-amplitude (K2) (secondary) | 61.66±0.02 km/s |
| Details[5] | |
| ο Leo Aa | |
| Mass | 2.074±0.013 M☉ |
| Radius | 5.73±0.34 R☉ |
| Luminosity | 41.1+5.8 −5.1 L☉ |
| Temperature | 6,107±93 K |
| Metallicity [Fe/H] | 0.11±0.10 dex |
| Age | 1.06±0.03 Gyr |
| ο Leo Ab | |
| Mass | 1.841±0.011 M☉ |
| Radius | 2.43±0.35 R☉ |
| Luminosity | 17.8+5.7 −4.3 L☉ |
| Temperature | 7,600±200 K |
| Age | 1.06±0.03 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Omicron Leonis (ο Leonis, abbreviated Omicron Leo, ο Leo) is a binary star 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]
The system consists of Omicron Leonis Aa (officially named Subra /ˈsuːbrə/, the traditional name for the system)[8][9] and Omicron Leonis 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).[10]
It bore the traditional name Subra, from the Arabic زبرة zubra (upper part of the back), originally applied to Delta and Theta Leonis.[11]
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[12] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] 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.[9]
In Chinese astronomy, this star is named Taimin (太民); it and ρ Leonis (Shaomin, 少民) are the two southernmost stars of the Xuanyuan (轩辕) constellation.[14]
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.[15] Their combined apparent magnitude is +3.52.
The system has an optical companion, component B, 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.[16] It is only close in the line of sight, being an unrelated background star which is a little more massive and hotter than the Sun.[17]
References
- ↑ 1.0 1.1 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237: 0. Bibcode: 2002yCat.2237....0D.
- ↑ Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series 143 (2): 513. doi:10.1086/342942. Bibcode: 2002ApJS..143..513G.
- ↑ 4.0 4.1 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 5.0 5.1 5.2 Gallenne, A.; Mérand, A.; Kervella, P.; Graczyk, D.; Pietrzyński, G.; Gieren, W.; Pilecki, B. (2023-04-01). "The Araucaria project: High-precision orbital parallaxes and masses of binary stars. I. VLTI/GRAVITY observations of ten double-lined spectroscopic binaries". Astronomy and Astrophysics 672: A119. doi:10.1051/0004-6361/202245712. ISSN 0004-6361. Bibcode: 2023A&A...672A.119G.
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ Herr, Richard B. (April 1969). "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon". Publications of the Astronomical Society of the Pacific 81 (479): 105. doi:10.1086/128748. Bibcode: 1969PASP...81..105H.
- ↑ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
- ↑ 9.0 9.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/.
- ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
- ↑ Jim Kaler's website: http://stars.astro.illinois.edu/sow/subra.html (online 6th Sep 2015)
- ↑ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. https://www.iau.org/science/scientific_bodies/working_groups/280/.
- ↑ "WG Triennial Report (2015-2018) - Star Names". p. 5. https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf.
- ↑ "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ Hummel, C. A.; Carquillat, J. -M.; Ginestet, N.; Griffin, R. F.; Boden, A. F.; Hajian, A. R.; Mozurkewich, D.; Nordgren, T. E. (2001). "Orbital and Stellar Parameters of Omicron Leonis from Spectroscopy and Interferometry". The Astronomical Journal 121 (3): 1623. doi:10.1086/319391. Bibcode: 2001AJ....121.1623H.
- ↑ "Washington Double Star Catalog". United States Naval Observatory. http://ad.usno.navy.mil/wds/.
- ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
External links
- Omicron Leo/Subra in Kaler Stars [1]
- Subra (HIP 47508) Relates to the A star, Subra-B
- Subra - Omi Leonis brief data.
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