Astronomy:HD 198404

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Short description: Star with an optical companion
HD 198404
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Delphinus
Right ascension  20h 49m 59.0925s[1]
Declination +05° 32′ 40.5081″[1]
Apparent magnitude (V) 6.19±0.01[2]
Characteristics
Spectral type K0[3]
U−B color index +0.79[4]
B−V color index +0.98[4]
Astrometry
Radial velocity (Rv)−21.63±0.31[5] km/s
Proper motion (μ) RA: +43.408[1] mas/yr
Dec.: −0.174[1] mas/yr
Parallax (π)8.2537 ± 0.1261[1] mas
Distance395 ± 6 ly
(121 ± 2 pc)
Absolute magnitude (MV)+0.7[6]
Details
Mass3.12[7] M☉
Radius10.54[8] R☉
Luminosity56.3[9] L☉
Surface gravity (log g)2.8[7] cgs
Temperature4,809[10] K
Metallicity [Fe/H]+0.17[7] dex
Other designations
BD+05°4626, GC 29044, HD 198404, HIP 102833, HR 7975, SAO 126267, WDS J20500+0533A[11][12]
Database references
SIMBADdata

HD 198404 (HR 7975) is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.19,[2] allowing it to be faintly seen with the naked eye. Parallax measurements place the object at a distance of 395 light years[1] and it is approaching the Solar System with a heliocentric radial velocity of −21.6 km/s.[5]

HD 198404 has a simple stellar classification of K0,[3] indicating that it is a K-type star. Its enlarged diameter of 10.54 R☉[8] and its low surface gravity[7] suggest that it has evolved away from the main sequence to become a giant star.[7] HD 198404 has 3.12 times the mass of the Sun[7] and radiates at 56 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 4,809 K,[10] giving it a yellowish orange hue. The star is metal enriched, having an iron abundance 48% greater than that of the Sun.[7]

HD 198404 has an optical companion located 78.2″ away along a position angle of 127° (as of 2014).[13]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H. 
  3. ↑ 3.0 3.1 Cannon, Annie Jump; Pickering, Edward Charles (1923). "The Henry Draper catalogue : 19h and 20h". Annals of Harvard College Observatory 98: 1. Bibcode: 1923AnHar..98....1C. 
  4. ↑ 4.0 4.1 Cousins, A. W. J. (16 November 1964). "Photometric Data for Stars in the Equatorial Zone (Seventh List)". Monthly Notes of the Astronomical Society of South Africa 23: 175. ISSN 0024-8266. Bibcode: 1964MNSSA..23..175C. 
  5. ↑ 5.0 5.1 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. doi:10.1051/0004-6361:20041272. Bibcode: 2005A&A...430..165F. 
  6. ↑ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation" (in en). Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Sato, Bun'ei; Takeda, Y.; Li, H. N. (31 March 2014). "The Lithium Abundances of a Large Sample of Red Giants". The Astrophysical Journal 785 (2): 94. doi:10.1088/0004-637X/785/2/94. ISSN 0004-637X. Bibcode: 2014ApJ...785...94L. 
  8. ↑ 8.0 8.1 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics 657: A7. doi:10.1051/0004-6361/202142146. ISSN 0004-6361. Bibcode: 2022A&A...657A...7K. 
  9. ↑ 9.0 9.1 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society 427 (1): 343–357. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. Bibcode: 2012MNRAS.427..343M. 
  10. ↑ 10.0 10.1 Anders, F. et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. Bibcode: 2019A&A...628A..94A. 
  11. ↑ "HR 7975". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+7975. 
  12. ↑ 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. 
  13. ↑ 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. doi:10.1086/323920. ISSN 0004-6256. Bibcode: 2001AJ....122.3466M. 



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