HD 187123 is a single,[7] yellow-hued star with two exoplanetary companions in the northern constellation of Cygnus. It has an apparent visual magnitude of 7.83,[2] making it an 8th magnitude star that is too faint to be visible with the naked eye. However, it should be easy _target with binoculars or small telescope. The system is located at a distance of 150 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −17 km/s.[1]
 HD 187123 has a planetary system with at least two planets in it. Artist's rendition of planets HD 187123 b and c. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 46m 58.1122s[1] |
| Declination | +34° 25′ 10.281″[1] |
| Apparent magnitude (V) | 7.83[2] |
| Characteristics | |
| Spectral type | G2V[3] |
| B−V color index | 0.661±0.010[2] |
| Astrometry | |
| Radial velocity (Rv) | −16.91(12)[1] km/s |
| Proper motion (μ) | RA: 142.591(15) mas/yr[1] Dec.: −123.715(18) mas/yr[1] |
| Parallax (π) | 21.7166 ± 0.0157 mas[1] |
| Distance | 150.2 ± 0.1 ly (46.05 ± 0.03 pc) |
| Absolute magnitude (MV) | 4.41[2] |
| Details | |
| Mass | 1.06±0.02[4] M☉ |
| Radius | 1.17±0.03[4] R☉ |
| Luminosity | 1.44±0.02[4] L☉ |
| Surface gravity (log g) | 4.32±0.03[4] cgs |
| Temperature | 5,853±53[4] K |
| Metallicity [Fe/H] | 0.121±0.030[5] dex |
| Rotational velocity (v sin i) | 2.15±0.50[5] km/s |
| Age | 5.6±1.3[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an ordinary G-type main-sequence star with a stellar classification of G2V.[3] The physical properties of this star are sufficiently similar to the Sun that it has been considered a solar analog, although the metallicity is higher.[8] It is estimated to be five or six billion years old and is spinning with a projected rotational velocity of 2 km/s.[5] The star has a similar mass to the Sun but is slightly larger with 117% of the Sun's radius. It is radiating 1.44 times the luminosity of the Sun from its photosphere at an effective temperature of 5,853 K.[4]
Planetary system
editIn 1998 the California and Carnegie Planet Search team, after following a suggestion by Kevin Apps, a Briton who at the time was an undergraduate student[9] found a possible planet orbiting the star.[10] There were also indications of another, more distant body orbiting the star and this claim was published in 2006.[11] This planet was confirmed in 2009.[12] The presence of water has been detected in the atmosphere of HD 187123 b with high confidence.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.5074±0.0026 MJ | 0.04213±0.00034 | 3.0965886±0.0000043 | 0.0093±0.0046 | — | — |
| c | >1.818±0.035 MJ | 4.417±0.054 | 3324±46 | 0.280±0.022 | — | — |
See also
edit- List of extrasolar planets
- List of exoplanets discovered before 2000 - HD 187123 b
- List of exoplanets discovered between 2000–2009 - HD 187123 c
References
edit- ^ a b c d e f 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 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 Gray, R. O.; et al. (2001). "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars". The Astronomical Journal. 121 (4): 2148. Bibcode:2001AJ....121.2148G. doi:10.1086/319956. S2CID 117076031.
- ^ a b c d e f g 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 Feng, Y. Katherina; et al. (2015). "The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-period Planets". The Astrophysical Journal. 800 (1). 22. arXiv:1501.00633. Bibcode:2015ApJ...800...22F. doi:10.1088/0004-637X/800/1/22. S2CID 56390823.
- ^ "HD 187123". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-14.
- ^ Ginski, C.; et al. (April 2012). "A lucky imaging multiplicity study of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 421 (3): 2498–2509. arXiv:1202.4586. Bibcode:2012MNRAS.421.2498G. doi:10.1111/j.1365-2966.2012.20485.x.
- ^ Soubiran, C.; Triaud, A. (May 2004). "The Top Ten solar analogs in the ELODIE library". Astronomy and Astrophysics. 418 (3): 1089–1100. arXiv:astro-ph/0402094. Bibcode:2004A&A...418.1089S. doi:10.1051/0004-6361:20035708.
- ^ "British student shows Nasa new planet". BBC News. September 25, 1998. Retrieved December 31, 2011.
- ^ Butler, R. Paul; et al. (1998). "A Planet with a 3.1 Day Period around a Solar Twin". Publications of the Astronomical Society of the Pacific. 110 (754): 1389–1393. Bibcode:1998PASP..110.1389B. CiteSeerX 10.1.1.37.5463. doi:10.1086/316287. S2CID 16360564.
- ^ Wright, J. T.; et al. (2007). "Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars". The Astrophysical Journal. 657 (1): 533–545. arXiv:astro-ph/0611658. Bibcode:2007ApJ...657..533W. doi:10.1086/510553. S2CID 35682784.
- ^ Wright, J. T.; et al. (2009). "Ten New and Updated Multi-planet Systems, and a Survey of Exoplanetary Systems". The Astrophysical Journal. 693 (2): 1084–1099. arXiv:0812.1582. Bibcode:2009ApJ...693.1084W. doi:10.1088/0004-637X/693/2/1084. S2CID 18169921.
- ^ Buzard, Cam; et al. (July 2020). "Simulating the Multi-epoch Direct Detection Technique to Isolate the Thermal Emission of the Non-transiting Hot Jupiter HD187123b". The Astronomical Journal. 160 (1): 13. arXiv:2005.03020. Bibcode:2020AJ....160....1B. doi:10.3847/1538-3881/ab8f9c. S2CID 218538482. 1.
External links
edit- "Notes for star HD 187123". Extrasolar Planets Encyclopaedia. Archived from the original on June 20, 2006. Retrieved 2008-08-25.