Wikipedia

HD 195479

HD 195479, also designated as HR 7839, is a solitary star located in the northern constellation Delphinus, the dolphin. It has an apparent magnitude of 6.20,[2] placing it near the limit for naked eye visibility, even under ideal conditions. The object is located relatively close at a distance of 288 light-years based on Gaia DR3 parallax measurements[1] and it is drifting closer with a heliocentric radial velocity of −40.1 km/s.[5] At its current distance, HD 195479's brightness is diminished by an interstellar extinction of 0.27 magnitudes[14] and it has an absolute magnitude of +1.53.[6]

HD 195479
Location of HD 195479 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Delphinus
Right ascension 20h 30m 58.26388s[1]
Declination +20° 36′ 23.0762″[1]
Apparent magnitude (V) 6.20±0.01[2]
Characteristics
Spectral type kA1 hA9 mF2[3]
U−B color index +0.13[4]
B−V color index +0.12[4]
Astrometry
Radial velocity (Rv)−40.1±1.6[5] km/s
Proper motion (μ) RA: +95.633 mas/yr[1]
Dec.: +58.78 mas/yr[1]
Parallax (π)11.3074 ± 0.0337 mas[1]
Distance288.4 ± 0.9 ly
(88.4 ± 0.3 pc)
Absolute magnitude (MV)+1.53[6]
Details
Mass2.05+0.38
−0.24[7] M☉
Radius2.15±0.11[8] R☉
Luminosity38.96+0.36
−0.42[1] L☉
Surface gravity (log g)4.08[9] cgs
Temperature8,454[10] K
Metallicity [Fe/H]−0.11[11] dex
Rotational velocity (v sin i)18.0±0.6[9] km/s
Age631[12] Myr
Other designations
AG+20°2271, BD+20°4602, GC 28540, HD 195479, HIP 101213, HR 7839, SAO 88783, CCDM J20310+2036A, WDS J20310+2036A, TIC 379435621[13]
Database references
SIMBADdata

HD 195479 is an Am star with a stellar classification of kA1hA9mF2.[3] The notion indicates that it has the calcium K-lines of an A1 star, the hydrogen lines of an A9 star, and the metallic lines of a F2 star. It has 2.05 times the mass of the Sun[7] and 2.15 times the radius of the Sun.[8] It radiates 38.96 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 8,454 K,[10] giving it white hue when viewed in the night sky. HD 195479 is deficient in iron, having an abundance 77.6% of the Sun's.[11] It is estimated to be 631 million years old[12] and it spins modestly with a projected rotational velocity of 18.0 km/s,[9] common for Am stars.

The star has two optical companions: a 12th magnitude star designated B located 5.7" away along a position angle of 88° and a 13th magnitude star designated C located 55.9" away along a position angle of 206°.[15] They were both observed by American astronomer Sherburne Wesley Burnham during the late 19th century.[16] B and C are both background stars that are far more distant than HD 195479.[17][18]

References

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  1. ^ a b c d e f g 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 Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (March 2002). "The Tycho double star catalogue". Astronomy & Astrophysics. 384 (1): 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822. eISSN 1432-0746. ISSN 0004-6361.
  3. ^ a b Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182. ISSN 0067-0049. S2CID 120495962.
  4. ^ a b Mendoza, E. E.; Gomez, V. T.; Gonzalez, S. (June 1978). "UBVRI photometry of 225 AM stars". The Astronomical Journal. 83: 606. Bibcode:1978AJ.....83..606M. doi:10.1086/112242. S2CID 121449759.
  5. ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
  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 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.
  8. ^ 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.
  9. ^ a b c Shorlin, S. L. S.; Wade, G. A.; Donati, J.-F.; Landstreet, J. D.; Petit, P.; Sigut, T. A. A.; Strasser, S. (2002). "A highly sensitive search for magnetic fields in B, A and F stars". Astronomy & Astrophysics. 392 (2): 637–652. Bibcode:2002A&A...392..637S. doi:10.1051/0004-6361:20021192. ISSN 0004-6361. S2CID 1706867.
  10. ^ a b 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.
  11. ^ a b Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv:2111.01860. Bibcode:2022A&A...658A..91A. doi:10.1051/0004-6361/202142369. eISSN 1432-0746. ISSN 0004-6361.
  12. ^ a b Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. eISSN 1562-6873. ISSN 1063-7737. S2CID 118345778.
  13. ^ "HD 195479". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 13, 2024.
  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. ^ 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.
  16. ^ Burnham, S. W. (November 1875). "Sixth Catalogue of 90 new double stars discovered with a 6‐inch refractor". Astronomische Nachrichten. 86 (22). Wiley: 337–350. Bibcode:1875AN.....86..337B. doi:10.1002/asna.18750862202. ISSN 0004-6337. S2CID 121918815.
  17. ^ 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.
  18. ^ 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.
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