Wikipedia

HD 85709

HD 85709 (HR 3915; 14 G. Sextantis; NSV 18292) is a solitary star[15] located in the equatorial constellation Sextans. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.95.[2] The object is located relatively far at a distance of 1,100 light-years based on Gaia DR3 parallax measurements but it is slowly drifting closer with a heliocentric radial velocity of −0.66 km/s.[8] At its current distance, HD 85709's brightness is diminished with an interstellar extinction of two-tenths of a magnitude[16] and it has an absolute magnitude of −1.30.[9]

HD 85709
Location of HD 85709 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 09h 53m 42.92424s[1]
Declination +05° 57′ 30.8742″[1]
Apparent magnitude (V) 5.95[2] (5.89 - 5.95)[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M2.5 III[5]
U−B color index +1.93[6]
B−V color index +1.66[6]
Variable type suspected[7]
Astrometry
Radial velocity (Rv)−0.66±0.40[8] km/s
Proper motion (μ) RA: −3.026 mas/yr[1]
Dec.: +1.315 mas/yr[1]
Parallax (π)2.9474 ± 0.107 mas[1]
Distance1,110 ± 40 ly
(340 ± 10 pc)
Absolute magnitude (MV)−1.30[9]
Details
Radius133±7[10] R☉
Luminosity1,918±144[11] L☉
Surface gravity (log g)0.469[12] cgs
Temperature3,622±125[12] K
Metallicity [Fe/H]+0.23[13] dex
Other designations
14 G. Sextantis[14], NSV 18292, AG+06°1262, BD+06°2224, GC 13608, HD 85709, HIP 48519, HR 3915, SAO 117975
Database references
SIMBADdata

HD 85709 has a stellar classification of M2.5 III,[5] indicating that it is an evolved M-type giant star. It is currently on the asymptotic giant branch,[4] the point where it is generating energy via the fusion of hydrogen and helium shells around an inert carbon core. Having expanded to 133 times the radius of the Sun,[10] it now radiates 1,918 times the luminosity of the Sun[11] from its enlarged photosphere at an effective temperature of 3,622 K.[12] HD 85709 is metal enriched with an iron abundance 1.58 times that of the Sun's.[13]

In 1991, astronomer V.G. Kornilov and colleagues observed that HD 85709 fluctuated between magnitudes 5.89 and 5.95 in optical light during a photometry survey.[3] As of 2004 however, its variability has not been confirmed.[17]

References

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  1. ^ 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.
  2. ^ a b Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ a b Kornilov, V. G.; Volkov, I. M.; Zakharov, A. I.; Kozyreva, V. S.; Kornilova, L. N.; Krutyakov, A. N.; Krylov, A. V.; Kusakin, A. V.; Leont'ev, S. E.; Mironov, A. V.; Moshkalev, V. G.; Pogrosheva, T. M.; Sementsov, V. N.; Khaliullin, Kh. F. (1991). "Catalogue of WBVR-magnitudes of bright stars of the northern sky". Trudy Gosudarstvennogo Astronomicheskogo Instituta. 63: 4–399. Bibcode:1991TrSht..63....1K. ISSN 0371-6791.
  4. ^ a b Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239. ISSN 0004-6256. S2CID 121672252.
  5. ^ a b Wilson, Ralph E.; Joy, Alfred H. (March 1950). "Radial Velocities of 2111 Stars". The Astrophysical Journal. 111: 221. Bibcode:1950ApJ...111..221W. doi:10.1086/145261. eISSN 1538-4357. ISSN 0004-637X. S2CID 122883647.
  6. ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  7. ^ Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
  8. ^ a b Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
  9. ^ 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.
  10. ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
  11. ^ 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.
  12. ^ a b c McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711. S2CID 73594365.
  13. ^ a b Zhou, Xu (August 1991). "The near-IR NA I doublet and CA II triplet in late-type stars and the determination of stellar atmosphere parameters". Astronomy and Astrophysics. 248: 367. Bibcode:1991A&A...248..367Z. ISSN 0004-6361.
  14. ^ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  15. ^ Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
  16. ^ 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.
  17. ^ Samus, N. N.; Durlevich, O. V. (November 2004). "VizieR Online Data Catalog: Combined General Catalogue of Variable Stars (Samus+ 2004)". VizieR Online Data Catalog: II/250. Bibcode:2004yCat.2250....0S.
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