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]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| 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 mas/yr[1] Dec.: −0.174 mas/yr[1] |
| Parallax (π) | 8.2537 ± 0.1261 mas[1] |
| Distance | 395 ± 6 ly (121 ± 2 pc) |
| Absolute magnitude (MV) | +0.7[6] |
| Details | |
| Mass | 3.12[7] M☉ |
| Radius | 10.54[8] R☉ |
| Luminosity | 56.3[9] L☉ |
| Surface gravity (log g) | 2.8[7] cgs |
| Temperature | 4,809[10] K |
| Metallicity [Fe/H] | +0.17[7] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
edit- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ 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.
- ^ a b 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.
- ^ a b 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. Bibcode:1964MNSSA..23..175C. ISSN 0024-8266.
- ^ 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.
- ^ 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.
- ^ a b c d e f g 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. arXiv:1404.1687. Bibcode:2014ApJ...785...94L. doi:10.1088/0004-637X/785/2/94. eISSN 1538-4357. ISSN 0004-637X.
- ^ a b Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b 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. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711.
- ^ a b 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. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361.
- ^ "HR 7975". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 21, 2022.
- ^ 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.
- ^ 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.