HD 121504 is a star with an orbiting exoplanet in the southern constellation of Centaurus. It is located at a distance of 136 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 19.6 km/s.[5] With an apparent visual magnitude of 7.54,[1] this star is too faint to be visible to the naked eye. It shows a high proper motion, traversing the celestial sphere at an angular rate of 0.270 arcsec yr−1.[8]

HD 121504
Observation data
Epoch J2000      Equinox J2000
Constellation Centaurus[1]
Right ascension 13h 57m 17.239s[2]
Declination −56° 02′ 24.16″[2]
Apparent magnitude (V) 7.54[1]
Characteristics
Spectral type G2V[3]
B−V color index 0.593±0.002[4][1]
Astrometry
Radial velocity (Rv)19.603±0.0004[5] km/s
Proper motion (μ) RA: −249.354 mas/yr[2]
Dec.: −84.570 mas/yr[2]
Parallax (π)24.0593 ± 0.0269 mas[2]
Distance135.6 ± 0.2 ly
(41.56 ± 0.05 pc)
Absolute magnitude (MV)4.27[1]
Details
Mass1.16±0.02[6] M
Radius1.15±0.03[6] R
Luminosity1.62±0.04[6] L
Surface gravity (log g)4.38±0.03[6] cgs
Temperature6,089±47[6] K
Metallicity [Fe/H]0.16[4] dex
Rotation8.6 days[4]
Rotational velocity (v sin i)2.6[4] km/s
Age1.9±1.0[6] Gyr
Other designations
CD−55°5427, GC 18842, HD 121504, HIP 68162, SAO 241321, WDS J13573-5602A, LTT 5432, NLTT 35734[7]
Database references
SIMBADdata
Exoplanet Archivedata

The spectrum of this star presents as an ordinary G-type main-sequence star, a yellow dwarf similar in appearance to the Sun, having a stellar classification of G2V.[3] It is roughly two billion years old and is spinning with a rotation period of 8.6 days. The star has 16% more mass than the Sun and a 15% greater radius.[6] The metallicity (the abundance of elements more massive than helium) is higher than solar.[4] The star is radiating 162% of the luminosity of the Sun from its photosphere at an effective temperature of 6,089 K.[6]

A nearby visual companion, designated as SAO 241323 has been proposed as a component of the system. However, the pair form an optical binary with an angular separation of 34.2″,[4] and in reality this is a white giant star located thousands of light years away.[citation needed]

Exoplanet

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In 2000 the Geneva Extrasolar Planet Search Team announced the discovery of an extrasolar planet orbiting the star.[9]

The HD 121504 planetary system[4]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b >1.22 MJ 0.33 63.33 ± 0.03 0.03 ± 0.01

See also

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References

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  1. ^ a b c d e 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
  2. ^ a b c d 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.
  3. ^ a b Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
  4. ^ a b c d e f g 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. arXiv:astro-ph/0310316. Bibcode:2004A&A...415..391M. doi:10.1051/0004-6361:20034250. S2CID 5233877.
  5. ^ a b Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv:1804.09370. Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID 52952408.
  6. ^ a b c d e f g h 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.
  7. ^ "HD 121504". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-04-03.
  8. ^ Luyten, W. J. (June 1995). "VizieR Online Data Catalog: NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode:1995yCat.1098....0L.
  9. ^ "European Southern Observatory: Six Extrasolar Planets Discovered". SpaceRef Interactive Inc. 7 August 2000. Retrieved 15 August 2009.