Wikipedia

HD 200779

HD 200779 (HIP 104092; Gliese 818; LHS 3624) is a solitary star located in the equatorial constellation Equuleus, the foal. It has an apparent magnitude of 8.27,[2] making it readily visible in binoculars but not to the naked eye. The object is located relatively close at a distance of 49 light years based on Gaia DR3 parallax measurements,[1] which makes it the nearest star in Equuleus.[13] It is classified as a high proper motion star,[12] with a total proper motion of 569 mas/yr.[1]

HD 200779
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Equuleus
Right ascension 21h 05m 19.74605s[1]
Declination +07° 04′ 09.4729″[1]
Apparent magnitude (V) 8.27[2]
Characteristics
Spectral type K6 V[3]
U−B color index +1.12[4]
B−V color index +1.21[4]
R−I color index +0.61[2]
Astrometry
Radial velocity (Rv)−66.94±0.18[5] km/s
Proper motion (μ) RA: +78.562 mas/yr[1]
Dec.: −563.909 mas/yr[1]
Parallax (π)66.4626 ± 0.0225 mas[1]
Distance49.07 ± 0.02 ly
(15.046 ± 0.005 pc)
Absolute magnitude (MV)+7.38[6]
Details
Mass0.68±0.01[7] M☉
Radius0.689+0.077
−0.050[8] R☉
Luminosity0.18[9] L☉
Surface gravity (log g)4.67±0.02[7] cgs
Temperature4,406±73[10] K
Metallicity [Fe/H]+0.05±0.06[7] dex
Rotational velocity (v sin i)5.1±1.2[5] km/s
Age6.33[11] Gyr
Other designations
AG+06°2882, BD+06°4741, GC 29447, GJ 818, HD 200779, HIP 104092, SAO 126533, CCDM J21054+0704A, WDS J21053+0704A, LFT 160, LHS 3624, LTT 16169[12]
Database references
SIMBADdata
ARICNSdata

At its current distance, HD 200779's brightness is diminished by only six hundredths of a magnitude due to interstellar dust[14] and it has an absolute magnitude of +7.38.[6] HD 200779 is expected to come within 7.76 parsecs (25.3 ly) of the Solar System in roughly 160,000 years.[15]

HD 200779 is an ordinary K-type main-sequence star with a stellar classification of K6 V.[3] It has 68% the mass of the Sun[7] and 69% of its radius.[8] However, it only radiates 18% the luminosity of the Sun[9] from its photosphere at an effective temperature of 4,406 K,[10] giving it an orange hue. It has an iron abundance slightly above solar level at [Fe/H] = +0.05[7] and it is estimated to be 6.33 billion years old.[11] HD 200779 spins modestly with a projected rotational velocity of 5.1 km/s.[5] The star is generally considered to be chromospherically active.[3]

HD 200779 has two optical companions: a distant 11th magnitude star located 64.6" away and a 9th magnitude star located 169.4" away.[16]

References

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  1. ^ a b c d e f 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 c Koen, C.; Kilkenny, D.; van Wyk, F.; Marang, F. (21 April 2010). "UBV (RI)C JHK observations of Hipparcos-selected nearby stars". Monthly Notices of the Royal Astronomical Society. 403 (4): 1949–1968. Bibcode:2010MNRAS.403.1949K. doi:10.1111/j.1365-2966.2009.16182.x. eISSN 1365-2966. ISSN 0035-8711.
  3. ^ a b c Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I." The Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. eISSN 1538-3881. ISSN 0004-6256. S2CID 119417105.
  4. ^ a b Roman, Nancy G. (December 1955). "A Catalogue of High-Velocity Stars". The Astrophysical Journal Supplement Series. 2: 195. Bibcode:1955ApJS....2..195R. doi:10.1086/190021. eISSN 1538-4365. ISSN 0067-0049. S2CID 123076474.
  5. ^ a b c Tokovinin, A. A. (March 1992). "The frequency of low-mass companions to K and M stars in the solar neighbourhood". Astronomy and Astrophysics. 256: 121–132. Bibcode:1992A&A...256..121T. ISSN 0004-6361. S2CID 118239049.
  6. ^ a b 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
  7. ^ a b c d e Ramírez, I.; Fish, J. R.; Lambert, D. L.; Allende Prieto, C. (13 August 2012). "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets". The Astrophysical Journal. 756 (1): 46. arXiv:1207.0499. Bibcode:2012ApJ...756...46R. doi:10.1088/0004-637X/756/1/46. eISSN 1538-4357. ISSN 0004-637X. S2CID 119199829.
  8. ^ a b 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. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
  9. ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  10. ^ a b Luck, R. Earle (13 February 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 111. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. eISSN 1538-3881. S2CID 125765376.
  11. ^ a b Dotter, Aaron; Chaboyer, Brian; Jevremović, Darko; Kostov, Veselin; Baron, E.; Ferguson, Jason W. (September 2008). "The Dartmouth Stellar Evolution Database". The Astrophysical Journal Supplement Series. 178 (1): 89–101. arXiv:0804.4473. Bibcode:2008ApJS..178...89D. doi:10.1086/589654. eISSN 1538-4365. ISSN 0067-0049. S2CID 119290835.
  12. ^ a b "HD 2007799". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 23, 2023.
  13. ^ Kirkpatrick, J. Davy; Marocco, Federico; Gelino, Christopher R.; Raghu, Yadukrishna; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella C.; Schurr, Steven D.; Apps, Kevin; Schneider, Adam C.; Meisner, Aaron M.; Kuchner, Marc J.; Caselden, Dan; Smart, R. L.; Casewell, S. L.; Raddi, Roberto (2024-04-01). "The Initial Mass Function Based on the Full-sky 20 pc Census of ∼3600 Stars and Brown Dwarfs". The Astrophysical Journal Supplement Series. 271 (2): 55. arXiv:2312.03639. Bibcode:2024ApJS..271...55K. doi:10.3847/1538-4365/ad24e2. ISSN 0067-0049.
  14. ^ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
  15. ^ Bailer-Jones, C. A. L. (19 February 2015). "Close encounters of the stellar kind". Astronomy & Astrophysics. 575: A35. arXiv:1412.3648. Bibcode:2015A&A...575A..35B. doi:10.1051/0004-6361/201425221. eISSN 1432-0746. ISSN 0004-6361. S2CID 59039482.
  16. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256. S2CID 119533755.
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