HD 70642

HD 70642 is a star with an exoplanetary companion in the southern constellation of Puppis. It has an apparent visual magnitude of +7.17,[2] which is too dim to be readily visible to the naked eye. The system is located at a distance of 95.5 light-years (29.3 parsecs) from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +49.3 km/s.[1] It came to within 55.3 ly of the Solar System some 329,000 years ago.[2]

HD 70642
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Puppis
Right ascension 08h 21m 28.13685s[1]
Declination −39° 42′ 19.4843″[1]
Apparent magnitude (V) +7.17[2]
Characteristics
Spectral type G6V CN+0.5[3]
B−V color index 0.692±0.022[2]
Astrometry
Radial velocity (Rv)+49.31±0.12[1] km/s
Proper motion (μ) RA: −201.729 mas/yr[1]
Dec.: 225.102 mas/yr[1]
Parallax (π)34.1478 ± 0.0154 mas[1]
Distance95.51 ± 0.04 ly
(29.28 ± 0.01 pc)
Absolute magnitude (MV)+4.93[2]
Details
Mass1.04±0.02[4] M☉
Radius0.97±0.01[4] R☉
Luminosity0.917±0.004[4] L☉
Surface gravity (log g)4.47±0.02[4] cgs
Temperature5732±23[4] K
Metallicity [Fe/H]+0.17±0.04[5] dex
Rotational velocity (v sin i)1.57[6] km/s
Age1.9±1.1 Gyr[4]
3.8±2.6[6] Gyr
Other designations
CD−39°4247, GJ 304, HD 70642, HIP 40952, SAO 199126, LTT 3116[7]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

This may be considered to be a solar analog star, being similar in physical properties to the Sun.[5] It is a G-type main-sequence star with a stellar classification of G6V CN+0.5.[3] It is comparable to the age of the Sun, estimated to be in the range of 2–6 billion years old. Although chromospherically inactive a magnetic field has been detected.[5] This star has about the same mass and radius as the Sun, is slightly cooler and less luminous,[4] and is richer in abundance of iron relative to hydrogen.[5] It is spinning at a leisurely rate, showing a projected rotational velocity of 1.6 km/s.[6]

Planetary system

A long period planetary companion to HD 70642 was announced in 2003. This planet orbits in a circular orbit (e=0.034) at 3.232 AU.[8] The star is so like Sol that its habitable zone is in the same place (~ 1 AU). The jovian ensures the stability of an Earth-mass planet at 1 AU. This system is one of the most similar in conditions to the Solar System among currently known planetary systems.[9] In 2023, the inclination and true mass of HD 70642 b were determined via astrometry.[10]

The HD 70642 planetary system[10]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination Radius
b 3.9+0.29
−0.27 MJ		 3.295±0.021 5.751+0.038
−0.035		 0.04+0.034
−0.027		 29.9+2.6
−2.4 or 150.1+2.4
−2.6°		 —

See also

References
  1. 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. 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. Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  4. Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951.
  5. Fossati, L.; et al. (March 2013). "Detection of a magnetic field in three old and inactive solar-like planet-hosting stars". Astronomy & Astrophysics. 551: 4. arXiv:1302.0879. Bibcode:2013A&A...551A..85F. doi:10.1051/0004-6361/201220997. S2CID 53377473. A85.
  6. Costa Silva, A. R.; et al. (February 2020). "Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur". Astronomy & Astrophysics. 634: 10. arXiv:1912.08659. Bibcode:2020A&A...634A.136C. doi:10.1051/0004-6361/201936523. S2CID 209405391. A136.
  7. "HD 70642". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-09-04.
  8. Carter, Brad D.; et al. (2003). "A Planet in a Circular Orbit with a 6 Year Period". The Astrophysical Journal Letters. 593 (1): L43–L46. arXiv:astro-ph/0307066. Bibcode:2003ApJ...593L..43C. doi:10.1086/378185.
  9. Hinse, T. C.; et al. (2008). "Dynamics and stability of telluric planets within the habitable zone of extrasolar planetary systems - Numerical simulations of test particles within the HD 4208 and HD 70642 systems". Astronomy & Astrophysics. 488 (3): 1133–1147. Bibcode:2008A&A...488.1133H. doi:10.1051/0004-6361:200809822.
  10. Xiao, Guang-Yao; Liu, Yu-Juan; et al. (May 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics. 23 (5): 055022. arXiv:2303.12409. Bibcode:2023RAA....23e5022X. doi:10.1088/1674-4527/accb7e.
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