Astronomy:HD 181342
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 19h 21m 04.2304s[1] |
| Declination | −23° 37′ 10.4513″[1] |
| Apparent magnitude (V) | 7.55[2] |
| Characteristics | |
| Spectral type | K0 III[3] |
| B−V color index | +1.02[2] |
| Astrometry | |
| Radial velocity (Rv) | −0.76 ± 0.07[4] km/s |
| Proper motion (μ) | RA: −46.597±0.088[1] mas/yr Dec.: −30.158±0.074[1] mas/yr |
| Parallax (π) | 8.2778 ± 0.0475[1] mas |
| Distance | 394 ± 2 ly (120.8 ± 0.7 pc) |
| Absolute magnitude (MV) | 2.2 ± 0.2[2] |
| Details[4] | |
| Mass | 1.78 ± 0.11 M☉ |
| Radius | 4.55 ± 0.49 R☉ |
| Luminosity | 16.2 L☉ |
| Surface gravity (log g) | 3.42 ± 0.07 cgs |
| Temperature | 4976 ± 26 K |
| Metallicity [Fe/H] | +0.22 ± 0.05 dex |
| Rotational velocity (v sin i) | 1.92 ± 0.23 km/s |
| Age | 1.56 ± 0.28 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 181342 is a star with an orbiting exoplanet in the constellation of Sagittarius. With an apparent magnitude of 7.55,[2] it cannot be seen with the naked eye. Parallax measurements made by Gaia spacecraft put the star at a distance of 394 light-years (121 parsecs) away.[1] It is drifting closer with a heliocentric radial velocity of radial_v −0.8 km/s.[4]
The star HD 181342 is named Belel and the planetary companion is Dopere. The name was selected in the NameExoWorlds campaign by Senegal, during the 100th anniversary of the IAU. Belel is a rare source of water in the north of Senegal. Dopere is an expansive historical area in the north of Senegal where Belel was located.[6][7]
HD 181342 is a K-type red giant star with a stellar classification of K0 III.[3] It was formerly an A-type main-sequence star,[2] but at an age of 1.56 billion years it has swelled up to a size of 4.55 solar radii.[4] It is currently 1.78 times the mass of the Sun, 16.2 times as luminous, and its effective temperature is 4,976 K.[4]
A survey in 2015 ruled out the existence of any additional stellar companions at projected distances from 138 to 762 astronomical units.[8]
Planetary system
HD 181342 is known to have one planet, detected with Doppler spectroscopy.[2] The planet, HD 181342 b, orbits at a distance of 1.59 astronomical units (au), every 564 days (almost 2 years). Its mass is at least two and a half times that of Jupiter.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Dopere | ≥2.54±0.19 MJ | 1.592±0.091 | 564.1±4.1 | 0.022±0.051 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Johnson, John Asher et al. (2010). "Retired a Stars and Their Companions. IV. Seven Jovian Exoplanets from Keck Observatory". Publications of the Astronomical Society of the Pacific 122 (892): 701–711. doi:10.1086/653809. Bibcode: 2010PASP..122..701J.
- ↑ 3.0 3.1 Houk, N.; Smith-Moore, M. (1988). "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0.". Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 4. Bibcode: 1988mcts.book.....H.
- ↑ 4.0 4.1 4.2 4.3 4.4 Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; de la Villarmois, E. Artur; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics 574: A50. doi:10.1051/0004-6361/201424474. Bibcode: 2015A&A...574A..50J.
- ↑ "HD 181342". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+181342.
- ↑ "Approved names" (in en). http://www.nameexoworlds.iau.org/final-results.
- ↑ "International Astronomical Union | IAU". https://www.iau.org/news/pressreleases/detail/iau1912/.
- ↑ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society 450 (3): 3127–3136. doi:10.1093/mnras/stv771. Bibcode: 2015MNRAS.450.3127M. https://academic.oup.com/mnras/article/450/3/3127/1063872. Retrieved 19 June 2020.
- ↑ 9.0 9.1 Luhn, Jacob K. et al. (2019). "Retired A Stars and Their Companions. VIII. 15 New Planetary Signals around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts". The Astronomical Journal 157 (4): 149. doi:10.3847/1538-3881/aaf5d0. Bibcode: 2019AJ....157..149L.
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