Astronomy:HD 216770
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Piscis Austrinus |
| Right ascension | 22h 55m 53.708s[1] |
| Declination | –26° 39′ 31.54″[1] |
| Apparent magnitude (V) | 8.11[2] |
| Characteristics | |
| Spectral type | K0V[2] or G9VCN+1[3] |
| B−V color index | 0.821[2] |
| Astrometry | |
| Radial velocity (Rv) | 31.141±0.0004[4] km/s |
| Proper motion (μ) | RA: 226.237[1] mas/yr Dec.: −177.985[1] mas/yr |
| Parallax (π) | 27.2923 ± 0.0245[1] mas |
| Distance | 119.5 ± 0.1 ly (36.64 ± 0.03 pc) |
| Absolute magnitude (MV) | 5.22[2] |
| Details | |
| Mass | 0.74±0.07[5] M☉ |
| Radius | 0.93±0.02[5] R☉ |
| Luminosity | 0.79[2] L☉ |
| Surface gravity (log g) | 4.37±0.04[5] cgs |
| Temperature | 5,399±18[5] K |
| Metallicity [Fe/H] | 0.27[5] dex |
| Rotation | 35.6 d[2] |
| Rotational velocity (v sin i) | 1.4[2] km/s |
| Age | 3.1[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 216770 is a star with an orbiting exoplanet in the southern constellation of Piscis Austrinus. With an apparent visual magnitude of 8.11,[2] it is too faint to be visible to the naked eye. It is located at a distance of 120 light years from the Sun, as determined by parallax measurements, and is drifting further away with a radial velocity of 31.1 km/s.[4] The star shows a high proper motion, traversing the celestial sphere at an angular rate of 0.302 arcsec yr−1.[7]
The spectrum of HD 216770 presents as a late G-type main-sequence star, a yellow dwarf, with a stellar classification of G9VCN+1,[3] where the suffix notation indicates anomalously strong band of CN. The star is smaller than the Sun, with 74% of the Sun's mass and 93% of the Sun's radius.[5] It is about three billion years old and is spinning slowly with a rotation period of 35.6 days.[2] The abundance of iron, a measure of the metallicity of the star, is higher than solar. The star is radiating 79% of the luminosity of the Sun from its photosphere at an effective temperature of 5,399 K.[5]
In 2003 an exoplanet was announced orbiting it by the Geneva Extrasolar Planet Search team.[2] As the inclination of the orbital plane is unknown, only a lower bound on the mass of the object can be determined. It has at least 65% of the mass of Jupiter. The body has an eccentric orbit with a period of 118.5 days.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.65 MJ | 0.46 | 118.45 ± 0.55 | 0.37 ± 0.06 | — | — |
See also
References
- ↑ 1.0 1.1 1.2 1.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Mayor, M. et al. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE". Astronomy and Astrophysics 415 (1): 391–402. doi:10.1051/0004-6361:20034250. Bibcode: 2004A&A...415..391M.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 Soubiran, C. et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics 616: A7. doi:10.1051/0004-6361/201832795. Bibcode: 2018A&A...616A...7S.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Stassun, Keivan G. et al. (2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal 153 (3): 136. doi:10.3847/1538-3881/aa5df3. Bibcode: 2017AJ....153..136S.
- ↑ "HD 216770". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+216770.
- ↑ Luyten, W. J. (June 1995). "NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode: 1995yCat.1098....0L.
External links
- "Notes for star HD 216770". Extrasolar Planets Encyclopaedia. http://exoplanet.eu/star.php?st=HD+216770.
Coordinates: 
22h 55m 53.7097s, −26° 39′ 31.547″
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