Astronomy:Upsilon Leonis
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Leo |
| Right ascension | 11h 36m 56.92983s[1] |
| Declination | +00° 49′ 25.8758″[1] |
| Apparent magnitude (V) | 4.33[2] |
| Characteristics | |
| Spectral type | G9 III[3] |
| U−B color index | +0.76[2] |
| B−V color index | +1.00[2] |
| Astrometry | |
| Radial velocity (Rv) | 1.79±0.16[4] km/s |
| Proper motion (μ) | RA: +1.76[1] mas/yr Dec.: +43.37[1] mas/yr |
| Parallax (π) | 17.97 ± 0.22[1] mas |
| Distance | 182 ± 2 ly (55.6 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.59[5] |
| Details | |
| Mass | 2.58[5] M☉ |
| Radius | 11[4] R☉ |
| Luminosity | 56[4] L☉ |
| Surface gravity (log g) | 2.7[4] cgs |
| Temperature | 4,842[4] K |
| Metallicity [Fe/H] | –0.34[4] dex |
| Rotational velocity (v sin i) | 0.0[4] km/s |
| Age | 4.12±2.08[6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Upsilon Leonis (υ Leo) is a star in the zodiac constellation of Leo. It is visible to the naked eye with an apparent visual magnitude of 4.33.[2] The distance to this star, as determined using parallax measurements,[1] is about 182 light years. At that distance, the visual magnitude of the star is diminished by an estimated extinction factor of 0m.02 because of interstellar dust.[5]
With an age of around 4 billion years, this star has evolved into a G-type giant star with a stellar classification of G9 III.[3] It has 2.6 times the Sun's mass,[5] but has expanded to 11 times the solar radius and shines with 56 times the luminosity of the Sun at an effective temperature of 4,842 K.[4] The rate of rotation is too small to be measured, with a projected rotational velocity of 0.0 km/s.[4] The chemical abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is less than half that in the Sun.[4] It is most likely a member of the galactic thin disk population.[6]
Planetary system
In 2021, a gas giant planet was detected by radial velocity method.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.51+0.06−0.26 MJ | 1.18+0.11−0.32 | 385.2+2.8−1.3 | 0.320+0.134−0.218 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram 4: 1, Bibcode: 1962MtSOM...4....1B.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Massarotti, Alessandro et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 5.0 5.1 5.2 5.3 Takeda, Yoichi et al. (February 2005), "Stellar Parameters and Photospheric Abundances of Late-G Giants: Properties of the Targets of the Okayama Planet Search Program", Publications of the Astronomical Society of Japan 57 (1): 109–125, doi:10.1093/pasj/57.1.109, Bibcode: 2005PASJ...57..109T.
- ↑ 6.0 6.1 Soubiran, C. et al. (March 2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics 480 (1): 91–101, doi:10.1051/0004-6361:20078788, Bibcode: 2008A&A...480...91S.
- ↑ "* ups Leo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+ups+Leo.
- ↑ 8.0 8.1 Teng, Huan-Yu; Sato, Bun'ei; Takarada, Takuya; Omiya, Masashi; Harakawa, Hiroki; Izumiura, Hideyuki; Kambe, Eiji; Takeda, Yoichi et al. (2022), "Regular radial velocity variations in nine G- and K-type giant stars: Eight planets and one planet candidate", Publications of the Astronomical Society of Japan 74: 92–127, doi:10.1093/pasj/psab112
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