HD 187123

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]
Distance150.2 ± 0.1 ly
(46.05 ± 0.03 pc)
Absolute magnitude (MV)4.41[2]
Details
Mass1.06±0.02[4] M☉
Radius1.17±0.03[4] R☉
Luminosity1.44±0.02[4] L☉
Surface gravity (log g)4.32±0.03[4] cgs
Temperature5,853±53[4] K
Metallicity [Fe/H]0.121±0.030[5] dex
Rotational velocity (v sin i)2.15±0.50[5] km/s
Age5.6±1.3[4] Gyr
Other designations
BD+34°3708, HD 187123, HIP 97336, SAO 68845, LTT 15779[6]
Database references
SIMBADdata

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]

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

In 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]

The HD 187123 planetary system[5]
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

References

  1. 1 2 3 4 5 6 7 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.
  2. 1 2 3 4 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.
  3. 1 2 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.
  4. 1 2 3 4 5 6 7 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.
  5. 1 2 3 4 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.
  6. ↑ "HD 187123". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-14.
  7. ↑ 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.
  8. ↑ 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.
  9. ↑ "British student shows Nasa new planet". BBC News. September 25, 1998. Retrieved December 31, 2011.
  10. ↑ 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.
  11. ↑ 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.
  12. ↑ 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.
  13. ↑ 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.
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