HD 181342
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 19h 21m 04.23095s[1] |
| Declination | −23° 37′ 10.4528″[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: −45.87[1] mas/yr Dec.: −30.58[1] mas/yr |
| Parallax (π) | 9.04 ± 0.61[1] mas |
| Distance | 360 ± 20 ly (111 ± 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 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 Hipparcos put the star at a distance of 360 light-years (111 parsecs) away.[1]
HD 181342 is a K-type red giant star.[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 surface temperature is 4976 K.[4]
Planetary system
HD 181342 is known to have one planet, detected with Doppler spectroscopy. The planet, HD 181342 b, orbits at a distance of 1.78 astronomical units (au), every 663 days (almost 2 years). Its mass is at least 3.3 times that of Jupiter.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >3.3 ± 0.2 MJ | 1.78 ± 0.07 | 663 ± 29 | 0.177 ± 0.057 | — | — |
References
- 1 2 3 4 5 6 van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- 1 2 3 4 5 6 7 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. arXiv:1003.3445. Bibcode:2010PASP..122..701J. doi:10.1086/653809.
- 1 2 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.
- 1 2 3 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. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474.
- ↑ "HD 181342". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 3 September 2017.