HD 28204

HD 28204, also designated as HR 1401, is a spectroscopic binary^[16] located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.93,^[2] making it faintly visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 331 light-years and it is currently receding with a heliocentric radial velocity of 9 km/s.^[5] At its current distance, HD 28204's brightness is diminished by 0.18 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.91.^[6]

HD 28204

Location of HD 28204 on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Camelopardalis
Right ascension	04h 33m 30.68009s[1]
Declination	+72° 31′ 42.9803″[1]
Apparent magnitude (V)	5.93±0.01[2]
Characteristics
Spectral type	kA8 hF0 mF2[3]
U−B color index	+0.16[4]
B−V color index	+0.28[4]
Astrometry
Radial velocity (Rv)	9.0±0.9[5] km/s
Proper motion (μ)	RA: +30.055 mas/yr[1] Dec.: −90.625 mas/yr[1]
Parallax (π)	9.8596 ± 0.0214 mas[1]
Distance	330.8 ± 0.7 ly (101.4 ± 0.2 pc)
Absolute magnitude (MV)	+0.91[6]
Orbit[7]
Period (P)	4.1950 d
Eccentricity (e)	0.040±0.029[8]
Inclination (i)	28-43°
Periastron epoch (T)	2,426,034.6450 JD
Argument of periastron (ω) (secondary)	337±244[8]°
Semi-amplitude (K1) (primary)	31.3 km/s
Details
Aa
Mass	1.68[9] M☉
Radius	3.48±0.18[10] R☉
Luminosity	35.7±0.2[1] L☉
Surface gravity (log g)	3.58+0.10 −0.06[11] cgs
Temperature	7,320±157[12] K
Metallicity [Fe/H]	−0.14[13] dex
Rotational velocity (v sin i)	23±10[3] km/s
Age	1.103[14] Gyr
Ab
Mass	0.474[9] M☉
Other designations
AG+72°116, BD+72°227A, FK5 2333, GC 5478, HD 28204, HIP 21247, HR 1401, SAO 5238, ADS 3267 A, CCDM J04335+7232A, WDS J04335+7232A, TIC 103566595[15]
Database references
SIMBAD	data

HD 28204 is a single-lined spectroscopic binary consisting of an Am star and an unseen companion, as the primary is the only one detectable in the spectrum. With a mass of 0.474 M_☉,^[9] the companion might be a K-type main-sequence star. Both stars take 4.2 days to revolve around each other in a nearly circular orbit, which is somewhat constrained.^[7] HD 28204 has two optical companions: a 12th magnitude star located 39" away along a position angle of 257° and a 14th magnitude star located 27.3" along a position angle of 55°.^[17]

The visible component has a stellar classification of kA8hF0mF2,^[3] indicating that it is an Am star with the calcium K-lines of an A8 star, the hydrogen lines of a F0 star, and the metallic lines of a F2 star. It has 1.68 times the mass of the Sun^[9] and an enlarged radius 3.48 times that of the Sun.^[10] It radiates 35.7 times the luminosity of the Sun^[1] from its photosphere at an effective temperature of 7,320 K,^[12] giving it the typical white hue of an A-type star. It is slightly metal deficient with an iron abundance of [Fe/H] = −0.15 or 72% that of the Sun's.^[13] Like many Am stars it spins slowly, having a projected rotational velocity of 23 km/s.^[3]

References

1. 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. 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. S2CID 17128864.
3. 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. Oja, T. (April 1983). "UVB photometry of FK4 and FK4 Supplement stars". Astronomy and Astrophysics Supplement Series. 52: 131–134. Bibcode:1983A&AS...52..131O. ISSN 0365-0138.
5. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode:1953GCRV..C......0W. S2CID 120000732.
6. 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. Luyten, W. J. (1936). "A Rediscussion of the Orbits of Seventy-Seven Spectroscopic Binaries". The Astrophysical Journal. 84. American Astronomical Society: 85. Bibcode:1936ApJ....84...85L. doi:10.1086/143751. ISSN 0004-637X. S2CID 121750381.
8. Lucy, L. B.; Sweeney, M. A. (August 1971). "Spectroscopic binaries with circular orbits". The Astronomical Journal. 76. American Astronomical Society: 544. Bibcode:1971AJ.....76..544L. doi:10.1086/111159. ISSN 0004-6256.
9. Kraicheva, Z.; Popova, E.; Tutukov, A.; Yungelson, L. (July 1980). "Catalogue of physical parameters of spectroscopic binary stars". Bull. Inf. Centre Données Stellaires. 19: 71. Bibcode:1980BICDS..19...71K. S2CID 118298938.
10. 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. 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.
12. 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. 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. eISSN 1432-0746. ISSN 0004-6361. S2CID 131780028.
14. Gontcharov, G. A. (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. S2CID 118345778.
15. "HD 28204". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 30, 2023.
16. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (23 August 2004). "SB⁹: The ninth catalogue of spectroscopic binary orbits". Astronomy & Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. eISSN 1432-0746. ISSN 0004-6361. S2CID 119387088.
17. 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.