HD 20104

Last updated
HD 20104
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Camelopardalis [1]
A
Right ascension 03h 17m 31.527s [2]
Declination +65° 39′ 30.11″ [2]
Apparent magnitude  (V)7.05±0.01 [2]
B
Right ascension 03h 17m 31.593s [2]
Declination +65° 39′ 30.26″ [2]
Apparent magnitude  (V)7.39±0.01 [2]
Characteristics
A
Spectral type A2 V [3]
U−B color index +0.06 [4]
B−V color index +0.08 [4]
B
Spectral type A4V [3]
Astrometry
Radial velocity (Rv)−6±2 [5] km/s
Proper motion (μ)RA: −10.54 mas/yr [6]
Dec.: +5.84 mas/yr [6]
Parallax (π)5.92±0.65  mas [6]
Distance approx. 550  ly
(approx. 170  pc)
Absolute magnitude  (MV)+0.3 [1]
Orbit [7]
PrimaryHD 20104 A
CompanionHD 20104 B
Period (P)350 yr
Semi-major axis (a)0.46″
Eccentricity (e)0.4
Inclination (i)135°
Longitude of the node (Ω)58°
Periastron epoch (T)2055.0
Argument of periastron (ω)
(secondary)		100°
Details
A
Mass 2.46 [8]   M☉
B
Mass 2.27 [8]   M☉
Other designations
BD+65°338, GC 3893, HD 20104, HIP 15309, HR 967, SAO 12686, ADS 2436, WDS J03175+6540
Database references
SIMBAD The system
A
B

HD 20104 (HR 967) is a visual binary in the northern circumpolar constellation Camelopardalis. The system has a combined apparent magnitude of 6.41, [9] making it near naked eye visibility. When resolved in a large telescope, HD 20104 appears to be a pair of 7th magnitude A-type main-sequence stars with a separation of about 0.5″ . [10] Located approximately 550 light years away, [6] the system is approaching the Sun with a heliocentric radial velocity of −6  km/s . [5]

The system's stars have masses twice that of the Sun [8] and effective temperatures ranging from 8,100 to 8,700 K, [9] [11] typical of stars their type. The primary radiates at 71.3  L☉ [11] − over luminous for its class − and spins with a projected rotational velocity of 159  km/s . [12] HD 20104 has an age of 313 million years. [11]

References

  1. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 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 . ISSN   0004-6361.
  3. 1 2 Edwards, T. W. (April 1976). "MK classification for visual binary components". The Astronomical Journal. 81: 245. Bibcode:1976AJ.....81..245E. doi: 10.1086/111879 . ISSN   0004-6256.
  4. 1 2 Haupt, H. F.; Schroll, A. (1974). "Photoelektrische Photometrie von Shell-Sternen". Astronomy and Astrophysics Supplement Series. 15: 311–319. Bibcode:1974A&AS...15..311H. ISSN   0365-0138.
  5. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode:1953GCRV..C......0W.
  6. 1 2 3 4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi: 10.1051/0004-6361:20078357 . ISSN   0004-6361.
  7. ↑ Heintz, W. D. (July 1998). "Observations of Double Stars. XVIII". The Astrophysical Journal Supplement Series. 117 (2): 587–598. Bibcode:1998ApJS..117..587H. doi: 10.1086/313127 .
  8. 1 2 3 Cvetkovic, Zorica; Ninkovic, S. (2010). "On the component masses of visual binaries". Serbian Astronomical Journal. 180 (180): 71–80. Bibcode:2010SerAJ.180...71C. doi: 10.2298/SAJ1080071C .
  9. 1 2 Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; de Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (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.
  10. ↑ 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.
  11. 1 2 3 Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv: 1201.2052 . Bibcode:2012A&A...537A.120Z. doi: 10.1051/0004-6361/201117691 . ISSN   0004-6361. S2CID   55586789.
  12. ↑ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007). "Rotational velocities of A-type stars: III. Velocity distributions". Astronomy & Astrophysics. 463 (2): 671–682. arXiv: astro-ph/0610785 . Bibcode:2007A&A...463..671R. doi: 10.1051/0004-6361:20065224 . ISSN   0004-6361.
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