HD 180314 is a star with an orbiting substellar companion in the northern constellation of Lyra. It is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.61.[2] The distance to this system is 401 light years based on parallax measurements, but it is drifting closer with a heliocentric radial velocity of −73.9 km/s.[3] With high probability it is a member of the Hercules stream of co-moving stars.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 14m 50.209s[1] |
| Declination | +31° 51′ 37.26″[1] |
| Apparent magnitude (V) | 6.61[2] |
| Characteristics | |
| Evolutionary stage | giant[2] |
| Spectral type | K0 III[2] |
| B−V color index | +1.000[2] |
| Astrometry | |
| Radial velocity (Rv) | −73.87±0.20[3] km/s |
| Proper motion (μ) | RA: 46.844 mas/yr[1] Dec.: 20.444 mas/yr[1] |
| Parallax (π) | 8.1261 ± 0.0192 mas[1] |
| Distance | 401.4 ± 0.9 ly (123.1 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.931[2] |
| Details[3] | |
| Mass | 2.48±0.08 M☉ |
| Radius | 8.10±0.45 R☉ |
| Luminosity | 43.7 L☉ |
| Surface gravity (log g) | 3.06±0.10 cgs |
| Temperature | 4,997±30 K |
| Metallicity [Fe/H] | 0.22±0.04 dex |
| Age | 0.60±0.05 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved giant star of the K-type with a stellar classification of K0 III.[2] At the age of roughly 600 million years, it has exhausted the supply of hydrogen at its core and expanded away from the main sequence. It has 2.48 times the mass of the Sun and 8.10 times the Sun's radius. The star is radiating 44 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,997 K.[3]
The star is orbited by one substellar companion, HD 180314 b,[4] an object with a minimum mass 22 times that of Jupiter and hence likely to be a brown dwarf.[2] It orbits HD 180314 every 396 days with a semi-major axis of 1.4 AU. HD 180314 b's orbit is moderately eccentric, with an orbital eccentricity of 0.257.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >22 MJ | 1.4 | 396.03 ± 0.62 | 0.257 ± 0.010 | — | — |
References
edit- ^ a b c d 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 g h i Sato, Bun'ei; et al. (2010). "Substellar Companions to Evolved Intermediate-Mass Stars: HD 145457 and HD 180314". Publications of the Astronomical Society of Japan. 62 (4): 1063–69. arXiv:1005.2860. Bibcode:2010PASJ...62.1063S. doi:10.1093/pasj/62.4.1063. S2CID 119113950.
- ^ a b c d Maldonado, J.; et al. (2013). "The metallicity signature of evolved stars with planets". Astronomy & Astrophysics. 554: 2013. arXiv:1303.3418. Bibcode:2013A&A...554A..84M. doi:10.1051/0004-6361/201321082. S2CID 119289111.
- ^ a b "HD 180314". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 February 2014.
- ^ Ramya, P.; Reddy, Bacham E.; Lambert, David L.; Musthafa, M. M. (August 2016). "Chemical compositions and kinematics of the Hercules stream". Monthly Notices of the Royal Astronomical Society. 460 (2): 1356–1370. arXiv:1604.04821. Bibcode:2016MNRAS.460.1356R. doi:10.1093/mnras/stw852.
- ^ "Planet HD 180314 b". Extrasolar Planets Encyclopaedia. Retrieved 1 January 2016.