HD 177830
| Observation data EpochJ2000.0EquinoxJ2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h05m20.7732s[1] |
| Declination | +25° 55′ 14.373″[1] |
| Apparent magnitude(V) | 7.175 |
| Characteristics | |
| Spectral type | K0IV[2]/M4V[3] |
| Astrometry | |
| Radial velocity(Rv) | −71.86 ± 0.06[4]km/s |
| Proper motion(μ) | RA:−41.248(12)mas/yr[1] Dec.:−52.580(17)mas/yr[1] |
| Parallax(π) | 16.0063 ± 0.0165mas[1] |
| Distance | 203.8 ± 0.2ly (62.48 ± 0.06pc) |
| Details | |
| Mass | 1.48[5]M☉ |
| Radius | 2.99[5]R☉ |
| Surface gravity(logg) | 4.03[5]cgs |
| Temperature | 4948[5]K |
| Metallicity[Fe/H] | 0.55 ± 0.03[6]dex |
| Rotational velocity(vsini) | 2.54[5]km/s |
| Age | 4.4 ± 2.2[6]Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 177830is a 7thmagnitudebinary starsystem located approximately 205light-yearsaway in theconstellationofLyra.The primary star is slightly more massive than theSun,but cooler being atype Kstar. Therefore, it is asubgiantclearly more evolved than the Sun. In visuallightit is four times brighter than the Sun, but because of its distance, about 204light years,it is not visible to the unaided eye. Withbinocularsit should be easily visible.
The primary star is known to have twoextrasolar planetsorbiting around it.
Stellar system
[edit]The secondary star is aRed dwarfstar orbiting at a distance of 100 to 200AUwith a likely period of roughly 800 years.[3]
Planetary system
[edit]On November 1, 1999,[8]the discovery of a planet HD 177830 b was announced by theCalifornia and Carnegie Planet Searchteam using the very successfulradial velocity methodand an analysis on data released by the team performed by amateur astronomerPeter Jalowiczoralong with two other planets. This planet is nearly 50% more massive than Jupiter (MJ) and takes 407 days to orbit the star in an extremely circular orbit.[2]In 2000 a group of scientists proposed, based on preliminaryHipparcosastrometricalsatellitedata, that the orbital inclination of HD 177830 b is as little as 1.3°. If that was the case, the planet would have a mass of67MJ,making it abrown dwarfinstead of a planet. However, it is very unlikely that the planet would have such orbit. Furthermore, brown dwarfs with short orbits aroundsolar-mass(M☉) stars are exceedingly rare (the so-called "brown dwarf desert") making the claim even more unlikely.
On November 17, 2010, the discovery of a second planet HD 177830 c was announced along with four other planets. The planet has 50% the mass of Saturn and takes 111 days to orbit the star in a very eccentric orbit. This planet is in a near 4:1resonancewith the outer planet.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | ≥0.15 ± 0.03MJ | 0.5137 ± 0.0006 | 110.9 ± 0.3 | 0.3495 ± 0.0002 | — | — |
| b | ≥1.49 ± 0.03MJ | 1.2218 ± 0.0008 | 406.6 ± 0.4 | 0.009 ± 0.004 | — | — |
See also
[edit]- List of exoplanets discovered before 2000- HD 177830 b
- List of exoplanets discovered in 2010- HD 177830 c
References
[edit]- ^abcdVallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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.S2CID244398875. Gaia DR3 record for this sourceatVizieR.
- ^abVogt, Steven S.; et al. (2000)."Six New Planets from the Keck Precision Velocity Survey".The Astrophysical Journal.536(2): 902–914.arXiv:astro-ph/9911506.Bibcode:2000ApJ...536..902V.doi:10.1086/308981.
- ^abRoberts Jr., Lewis C.; et al. (2015)."Know the Star, Know the Planet. V. Characterization of the Stellar Companion to the Exoplanet Host Star HD 177830".The Astronomical Journal.150(4) 103.arXiv:1507.07913.Bibcode:2015AJ....150..103R.doi:10.1088/0004-6256/150/4/103.
- ^Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; 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.arXiv:1410.6422.Bibcode:2015A&A...574A..50J.doi:10.1051/0004-6361/201424474.S2CID53666931.
- ^abcdeFischer, Debra A.; Valenti, Jeff (2005)."The Planet-Metallicity Correlation".The Astrophysical Journal.622(2): 1102.Bibcode:2005ApJ...622.1102F.doi:10.1086/428383.
- ^abcdMeschiari, Stefano; et al. (2011)."The Lick-Carnegie Survey: Four New Exoplanet Candidates".The Astrophysical Journal.727(2) 117.arXiv:1011.4068.Bibcode:2011ApJ...727..117M.doi:10.1088/0004-637X/727/2/117.
- ^"HD 177830 -- Double or multiple star".SIMBADAstronomical Database.Centre de données astronomiques de Strasbourg.Retrieved2014-10-11.
- ^"Astronomers discover six new planets orbiting nearby stars"(Press release). Kamuela, Hawaii: W. M. Keck Observatory. November 1, 1999.RetrievedDecember 19,2017.
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