Summary
HD 220773 is a star with an orbiting exoplanet in the northern constellation of Pegasus. It has an apparent visual magnitude of 7.10,[1] which is too faint to be visible with the naked eye. The distance to this system, as determined by parallax measurements, is 165 light years,[2] but it is drifting closer with a radial velocity of −37.7 km/s.[5] The star shows a high proper motion, traversing the celestial sphere at an angular rate of 0.187 arcsec yr−1.[10]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus[1] |
| Right ascension | 23h 26m 27.445s[2] |
| Declination | +08° 38′ 37.84″[2] |
| Apparent magnitude (V) | 7.10[1] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | G0 V[3] or F9 V[4] |
| B−V color index | 0.602±0.005[1] |
| Astrometry | |
| Radial velocity (Rv) | −37.735±0.0009[5] km/s |
| Proper motion (μ) | RA: 27.096 mas/yr[2] Dec.: −222.458 mas/yr[2] |
| Parallax (π) | 19.7694 ± 0.0669 mas[2] |
| Distance | 165.0 ± 0.6 ly (50.6 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.57[1] |
| Details | |
| Mass | 1.154±0.003[6] M☉ |
| Radius | 1.73±0.02[6] R☉ |
| Luminosity | 3.16±0.01[6] L☉ |
| Surface gravity (log g) | 4.02±0.01[6] cgs |
| Temperature | 5,852±26[6] K |
| Metallicity [Fe/H] | 0.09±0.06[7] dex |
| Rotational velocity (v sin i) | 3.82±1.00[8] km/s |
| Age | 6.3±0.1[6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The spectrum of HD 220773 presents as a late type star F-type or early G-type main-sequence star with a stellar classification of F9 V[4] or G0 V,[3] respectively. It is older than the Sun, with an estimated age of 6.3 billion years,[6] and the magnetic activity in the chromosphere is at a low level.[7] The star has 15% greater mass than the Sun but the radius is 73% larger.[6] The abundance of iron, a measure of the star's metallicity, is slightly higher than solar.[7] It is radiating over three times the luminosity of the Sun from its photosphere at an effective temperature of 5,852 K.[6]
A survey in 2015 ruled out the existence of any additional stellar companions at projected distances from 31 to 337 astronomical units.[3]
Planetary system edit
The star is orbited by an exoplanet discovered in 2012. As the inclination of the orbital plane is unknown, only a lower bound on the mass can be determined. This object has at least 1.45 times the mass of Jupiter. It has a very eccentric orbit with a semimajor axis of around 5 AU, taking 10.2 years to complete an orbit.[7] If any inner terrestrial planets exist in the HD 220773 system, these must have eccentric orbits for the planetary system to remain stable over a long time period.[11]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.45±0.3 MJ | 4.94±0.2 | 3,724.7±463 | 0.51±0.1 | — | — |
References edit
- ^ a b c d e 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 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 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. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340.
- ^ a b Wittrock, Justin M.; et al. (2017). "Exclusion of Stellar Companions to Exoplanet Host Stars". The Astronomical Journal. 154 (5): 184. arXiv:1709.05315. Bibcode:2017AJ....154..184W. doi:10.3847/1538-3881/aa8d69. S2CID 55789971.
- ^ a b Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv:1804.09370. Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID 52952408.
- ^ a b c d e f g h i Bonfanti, A.; et al. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
- ^ a b c d Robertson, Paul; et al. (2012). "The McDonald Observatory Planet Search: New Long-period Giant Planets and Two Interacting Jupiters in the HD 155358 System". The Astrophysical Journal. 749 (1): 39. arXiv:1202.0265. Bibcode:2012ApJ...749...39R. doi:10.1088/0004-637X/749/1/39. S2CID 59273311.
- ^ Tejada Arevalo, Roberto A.; et al. (October 2021). "Further Evidence for Tidal Spin-up of Hot Jupiter Host Stars". The Astrophysical Journal. 919 (2): 138. arXiv:2107.05759. Bibcode:2021ApJ...919..138T. doi:10.3847/1538-4357/ac1429. 138.
- ^ "HD 220773". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 September 2020.
- ^ Luyten, W. J. (June 1995). "NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode:1995yCat.1098....0L.
- ^ Antoniadou, Kyriaki I.; Libert, Anne-Sophie (2018). "Puzzling out the coexistence of terrestrial planets and giant exoplanets. The 2/1 resonant periodic orbits". Astronomy & Astrophysics. A60: 615. arXiv:1804.04936. Bibcode:2018A&A...615A..60A. doi:10.1051/0004-6361/201732058. S2CID 119231621.
- ^ "Planet HD 220773 b". exoplanet.eu. Retrieved 2024-01-05.