HD 191806
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cygnus
Right ascension 20h 09m 28.30936s[1]
Declination +52° 16′ 34.8000″[1]
Apparent magnitude (V) 8.08±0.01[2]
Characteristics
Spectral type rG0V[3]
B−V color index +0.63[2]
Astrometry
Radial velocity (Rv)−15.33±0.13[1] km/s
Proper motion (μ) RA: 114.022±0.022 mas/yr[1]
Dec.: 91.296±0.022 mas/yr[1]
Parallax (π)15.1975 ± 0.0182 mas[1]
Distance214.6 ± 0.3 ly
(65.80 ± 0.08 pc)
Absolute magnitude (MV)+3.89[4]
Details
Mass1.1±0.1[5] M☉
Radius1.48+0.14
−0.13[6] R☉
Luminosity2.23±0.16[7] L☉
Surface gravity (log g)4.15±0.15[6] cgs
Temperature5,894+155
−86[5] K
Metallicity [Fe/H]+0.30±0.02[7] dex
Rotation20.6±6.9 d[7]
Rotational velocity (v sin i)3.3[7] km/s
Age2.9±0.4[7] Gyr
Other designations
AG+52°1354, BD+51°2782, HD 191806, HIP 99306, SAO 32320[8]
Database references
SIMBADdata
Exoplanet Archivedata

HD 191806 is a star located in the northern constellation Cygnus. With an apparent magnitude of 8.093, it's undetectable with the naked eye, but can be seen with binoculars. HD 191806 is currently placed at a distance of 215 light years based on parallax measurements and is drifting towards the Solar System with a spectroscopic radial velocity of −15.28 km/s.

HD 191806 has a stellar classification of G0V,[3] indicating that it is a G-type main sequence star. It has 110% the mass of the Sun[5] and a slightly enlarged radius of 1.48 R☉.[6] It radiates at 2.23 times the luminosity of the Sun[7] from its photosphere at an effective temperature of 5,894 K,[5] giving a yellow hue. HD 191806 is estimated to be about 3 billion years old and has a metallicity nearly twice of the Sun's.[7] It spins with a projected rotational velocity of 3.3 km/s, which corresponds to a rotational period of 21 days.[7]

Planetary System

Observations for exoplanets orbiting the star began in 2007 when it was selected by the N2K Consortium as a potential host due to its high metallicity.[9] After ten years of, a team of astronomers found a super Jupiter orbiting the star.[7] The star has a secular acceleration of >11 km/s, suggesting either the presence of a stellar companion or another planet.[7] In 2022, the inclination and true mass of HD 191806 b were measured via astrometry.[10]

The HD 191806 planetary system[10]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(years) 		Eccentricity Inclination Radius
b 9.334+0.919
−0.852 MJ 		2.749+0.106
−0.118 		4.390+0.027
−0.031 		0.213+0.029
−0.028 		66.519+5.830
−4.851° 		—

See also

References

  1. ^ a b c d e 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. ^ a b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
  3. ^ a b Pickles, A.; Depagne, É. (2010). "All-Sky Spectrally Matched UBVRI - ZY and u′ g′ r′ i′ z′ Magnitudes for Stars in the Tycho2 Catalog". Publications of the Astronomical Society of the Pacific. 122 (898): 1437. arXiv:1011.2020. Bibcode:2010PASP..122.1437P. doi:10.1086/657947. S2CID 54678796.
  4. ^ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. ISSN 1063-7737. S2CID 119257644.
  5. ^ a b c d Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256.
  6. ^ a b c Allende Prieto, C.; Lambert, D. L. (December 1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. ISSN 0004-6361.
  7. ^ a b c d e f g h i j Díaz, R. F.; et al. (July 2016). "The SOPHIE search for northern extrasolar planets". Astronomy & Astrophysics. 591: A146. arXiv:1604.07610. Bibcode:2016A&A...591A.146D. doi:10.1051/0004-6361/201628331. eISSN 1432-0746. ISSN 0004-6361.
  8. ^ "HD 191806". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-09.
  9. ^ Robinson, Sarah E.; Ammons, S. Mark; Kretke, Katherine A.; Strader, Jay; Wertheimer, Jeremy G.; Fischer, Debra A.; Laughlin, Gregory (April 2007). "The N2K Consortium. VII. Atmospheric Parameters of 1907 Metal‐rich Stars: Finding Planet‐Search Targets". The Astrophysical Journal Supplement Series. 169 (2): 430–438. arXiv:astro-ph/0701631. Bibcode:2007ApJS..169..430R. doi:10.1086/513108. eISSN 1538-4365. ISSN 0067-0049.
  10. ^ a b Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.


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