Astronomy:HD 85512

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Short description: Star in the constellation Vela
HD 85512
250px
HD 85512 imaged by the Digitized Sky Survey
Observation data
Equinox J2000.0]] (ICRS)
Constellation Vela
Right ascension  09h 51m 07.05180s[1]
Declination −43° 30′ 10.0237″[1]
Apparent magnitude (V) 7.66[citation needed]
Characteristics
Evolutionary stage main sequence[1]
Spectral type K6V[2]
U−B color index 1.12[citation needed]
B−V color index 1.18[citation needed]
V−R color index 0.71[citation needed]
Astrometry
Radial velocity (Rv)−9.78±0.12[1] km/s
Proper motion (μ) RA: 461.603[1] mas/yr
Dec.: −471.880[1] mas/yr
Parallax (π)88.6737 ± 0.0173[1] mas
Distance36.782 ± 0.007 ly
(11.277 ± 0.002 pc)
Absolute magnitude (MV)7.39[3]
Details[2][4]
Mass0.69 M☉
Radius0.533 ± 0.04[note 1] R☉
Luminosity (bolometric)0.126 ± 0.008 L☉
Surface gravity (log g)4.604±0.017 cgs
Temperature4404±10 K
Metallicity([Si/H] dex) -0.02
Metallicity [Fe/H]-0.28 dex
Rotation47.13 ± 6.98
Rotational velocity (v sin i)2.194±0.118 km/s
Age5.61 ± 0.61 Gyr
Other designations
CD−42°5678, Gaia DR2 5412947081287925504, GJ 370, HD 85512, HIP 48331, LHS 2201, 2MASS J09510700-4330097[5]
Database references
SIMBADdata

HD 85512 is a solitary K-type main-sequence star 36.8 light-years (11.3 parsecs) away in the constellation Vela. It is about 1 billion years older than the Sun. It is extremely chromospherically inactive, only slightly more active than Tau Ceti. It exhibits a long-term variability[2] and was thought to host one low-mass planet, although this is now doubtful.[6]

Proposed planetary system

On August 19, 2011, a ≥3.6 Earth-mass planet was discovered using HARPS that is "just inside" the habitable zone, along with the inner planets of e (or 82 G.) Eridani, and HD 192310 c in Capricornus. These two other systems are closer to Earth than this system.[7] Modelling at the time of the discovery announcement found that the planet could be cool enough to host liquid water if it has more than 50% cloud coverage,[8] but with revised models of the habitable zone two years later it was found to be too hot to be potentially habitable.[9] For a time it ranked fifth-best for habitability in the Planetary Habitability Laboratory's Habitable Exoplanets Catalog, which later listed it in an article about "false starts" in the search for potentially habitable exoplanets.[10]

In 2023, a study reassessed the radial velocity data of HD 85512. A signal was detected with a period of 51 days, inconsistent with the previously published 58-day orbital period of HD 85512 b, but consistent with previous estimates of the stellar rotation period. This indicates that the signal is very likely to be caused by the stellar rotation, rather than an orbiting planet.[6]: 25–27 [6]: 44  Due to this, the NASA Exoplanet Archive now considers this planet as a false positive detection.[11] A 2026 study concluded that the radial velocity variations are indeed attributable to stellar activity.[12]: 13 

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 Anglada-Escudé, Guillem; Butler, R. Paul (2012), "The HARPS-TERRA project. I. Description of the algorithms, performance, and new measurements on a few remarkable stars observed by HARPS", The Astrophysical Journal Supplement Series 200 (2): 15, doi:10.1088/0067-0049/200/2/15, Bibcode: 2012ApJS..200...15A 
  3. ↑ Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H. 
  4. ↑ Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES) I. Code description and dwarf stars catalogue Full table D.1
  5. ↑ "HD 85512". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+85512. 
  6. ↑ 6.0 6.1 6.2 Laliotis, Katherine; Burt, Jennifer A.; Mamajek, Eric E. et al. (22 February 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal 165 (4): 176. doi:10.3847/1538-3881/acc067. Bibcode: 2023AJ....165..176L. 
  7. ↑ Pepe, F. et al. (2011). "The HARPS search for Earth-like planets in the habitable zone. I. Very low-mass planets around HD 20794, HD 85512, and HD 192310". Astronomy and Astrophysics 534: A58. doi:10.1051/0004-6361/201117055. Bibcode: 2011A&A...534A..58P. http://www.aanda.org/articles/aa/full_html/2011/10/aa17055-11/aa17055-11.html. 
  8. ↑ Kaltenegger, L.; Udry, S.; Pepe, F. (2011). "A Habitable Planet around HD 85512?". arXiv:1108.3561 [astro-ph.EP].
  9. ↑ Kopparapu, Ravi Kumar et al. (2013). "Habitable Zones Around Main-Sequence Stars: New Estimates". The Astrophysical Journal 765 (2): 131. doi:10.1088/0004-637X/765/2/131. Bibcode: 2013ApJ...765..131K. 
  10. ↑ "False Starts: Potentially Habitable Exoplanets - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/library/notes/falsestarts. 
  11. ↑ Template:Cite exoplanet archive
  12. ↑ Boulkaboul, Amina; Sozzetti, Alessandro; Soubiran, Caroline; Damerdji, Yassine (2026-03-28). "Magnetic Activity Cycles and Rotation in Planet-hosting and Non-hosting Solar-type Stars". Research in Astronomy and Astrophysics. doi:10.1088/1674-4527/ae587e. ISSN 1674-4527. 

Notes

  1. ↑ From R=L4πσTeff4, where R is the radius, L is the luminosity, Teff is the effective surface temperature and σ is the Stefan–Boltzmann constant.

Coordinates: Sky map 09h 51m 07.1s, −43° 30′ 10″



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