| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 13h 34m 02.5394s [1] |
| Declination | +53° 43′ 42.698″ [1] |
| Apparent magnitude (V) | 8.06 [2] |
| Characteristics | |
| Spectral type | G0V [3] |
| B−V color index | 0.699±0.012 [4] |
| Astrometry | |
| Radial velocity (Rv) | −29.07±0.24 [4] km/s |
| Proper motion (μ) |
RA: −85.849(18)
mas/
yr
[1] Dec.: −78.888(20) mas/ yr [1] |
| Parallax (π) | 10.8643 ± 0.0180 mas [1] |
| Distance | 300.2 ± 0.5
ly (92.0 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.32 [2] |
| Details [5] | |
| Mass | 1.23±0.03 M☉ |
| Radius | 2.00±0.10 R☉ |
| Luminosity | 3.80±0.30 L☉ |
| Surface gravity (log g) | 3.93±0.02 cgs |
| Temperature | 5,741±35 K |
| Metallicity [Fe/H] | 0.16 [2] dex |
| Rotational velocity (v sin i) | 7.0 [2] km/s |
| Age | 5.4±0.5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | The star |
| planet b | |
| Exoplanet Archive | data |
HD 118203 is a star with an orbiting exoplanet located in the northern circumpolar constellation of Ursa Major. It has the proper name Liesma, which means flame, and it is the name of a character from the Latvian poem Staburags un Liesma (Staburags and Liesma). The name was selected in the NameExoWorlds campaign by Latvia, during the 100th anniversary of the IAU. [7] [8]
The apparent visual magnitude of HD 118203 is 8.06, [2] which means it is invisible to the naked eye but it can be seen using binoculars or a telescope. Based on parallax measurements, it is located at a distance of 300 light years from the Sun. [1] The star is drifting closer with a radial velocity of −29 km/s. [4] Based on its position and space velocity this is most likely (97% chance) an older thin disk star. [9] An exoplanet has been detected in a close orbit around the star. [10]
The spectrum of HD 118203 matches a G-type main-sequence star with a class of G0V. [3] It has a low level of chromospheric activity, which means a low level of radial velocity jitter for planet detection purposes. [10] The star has 1.23 [5] times the mass of the Sun and double the Sun's radius. It is around 5.4 billion years old and is spinning with a projected rotational velocity of 7.0 km/s. [2] HD 118203 is radiating 3.8 times the luminosity of the Sun from its photosphere at an effective temperature of 5,741 K. [5]
Exoplanet
In 2006, a hot Jupiter candidate was reported in an eccentric orbit around this star. It was discovered using the radial velocity method based on observation of high- metallicity stars begun in 2004. [10] In 2020, it was found that this is a transiting planet, which allowed the mass and radius of the body to be determined. This exoplanet has more than double the mass of Jupiter and a 13% greater radius. It is named Staburags. The fact that the parent star is among the brighter known planet hosts (as of 2020) makes it an interesting object for further study. [9]
| Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Staburags | 2.173+0.077 −0.080 MJ |
0.07082+0.00095 −0.00110 |
6.134980+0.000038 −0.000037 |
0.316±0.021 | 88.75+0.86 −1.0 ° |
1.133+0.031 −0.030 RJ |
See also
References
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211. Bibcode: 2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv: 1611.02897. Bibcode: 2017AJ....153...21L. doi: 10.3847/1538-3881/153/1/21. S2CID 119511744. 21.
- ^ a b Grieves, N.; et al. (December 2018). "Chemo-kinematics of the Milky Way from the SDSS-III MARVELS survey". Monthly Notices of the Royal Astronomical Society. 481 (3): 3244–3265. arXiv: 1803.11538. Bibcode: 2018MNRAS.481.3244G. doi: 10.1093/mnras/sty2431.
- ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971. Bibcode: 2012AstL...38..331A. doi: 10.1134/S1063773712050015. S2CID 119257644.
- ^ a b c Bonfanti, A.; et al. (2015). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: A5. arXiv: 1511.01744. Bibcode: 2016A&A...585A...5B. doi: 10.1051/0004-6361/201527297. S2CID 53971692.
- ^ "HD 118203". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-13.
- ^ "Approved names". NameExoworlds. Retrieved 2020-01-02.
- ^ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
- ^ a b c Pepper, Joshua; et al. (2020). "TESS Reveals HD 118203 b to be a Transiting Planet". The Astronomical Journal. 159 (6): 243. arXiv: 1911.05150. Bibcode: 2020AJ....159..243P. doi: 10.3847/1538-3881/ab84f2. S2CID 207930540.
- ^ a b c da Silva, R.; et al. (2006). "Elodie metallicity-biased search for transiting Hot Jupiters I. Two Hot Jupiters orbiting the slightly evolved stars HD118203 and HD149143". Astronomy and Astrophysics. 446 (2): 717–722. arXiv: astro-ph/0510048. Bibcode: 2006A&A...446..717D. doi: 10.1051/0004-6361:20054116. S2CID 18907493.
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