HD 27322

HD 27322, also known as HR 1342, is a binary star located in the northern circumpolar constellation Camelopardalis. The visible component is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.92.^[2] The object is located relatively close at a distance of 313 light-years based on Gaia DR3 parallax measurements,^[1] and it is drifting closer with a heliocentric radial velocity of approximately −13 km/s.^[7] At its current distance, HD 27322's brightness is diminished by 0.24 magnitudes due to interstellar extinction^[14] and it has an absolute magnitude of +0.98.^[8]

HD 27322

Location of HD 27322 on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Camelopardalis
Right ascension	04h 21m 51.80623s[1]
Declination	+56° 30′ 22.7351″[1]
Apparent magnitude (V)	5.92±0.01[2]
Characteristics
Evolutionary stage	main sequence star[3]
Spectral type	A3 V[4] or A2 IV-V[5]
U−B color index	+0.08[6]
B−V color index	+0.11[6]
Astrometry
Radial velocity (Rv)	−13±5[7] km/s
Proper motion (μ)	RA: −14.793 mas/yr[1] Dec.: +7.466 mas/yr[1]
Parallax (π)	10.4168 ± 0.0907 mas
Distance	313 ± 3 ly (96.0 ± 0.8 pc)
Absolute magnitude (MV)	+0.98[8]
Details
A
Mass	1.9±0.1[9] M☉
Radius	2.64+0.11 −0.10[10] R☉
Luminosity	54.7+1.0 −0.9[1] L☉
Surface gravity (log g)	3.88±0.14[11] cgs
Temperature	8,414+176 −173[3] K
Metallicity [Fe/H]	−0.25[12] dex
Rotational velocity (v sin i)	130±8[5] km/s
Age	640[11] Myr
B
Mass	1.30±0.04[9] M☉
Temperature	6,492±109[9] K
Metallicity [Fe/H]	−0.50[9] dex
Rotational velocity (v sin i)	20[9] km/s
Other designations
AG+56°463, BD+56°509, GC 5253, HD 27322, HIP 20380, HR 1342, SAO 24563[13]
Database references
SIMBAD	data

HD 27322 A has a stellar classification of A3 V,^[4] indicating that it is an ordinary A-type main-sequence star that is generating energy via hydrogen fusion at its core. Abt & Morell (1995) gave a hotter and slightly more evolved classification of A2 IV-V,^[5] indicating that it is an A-type star with a luminosity class intermediate between a main sequence star and a subgiant. At the age of 640 million years,^[11] HD 27322 A has completed 79.5% of its main sequence lifetime.^[3] It has 1.9 times the mass of the Sun^[9] and 2.64 times the radius of the Sun.^[10] It radiates 54.7 times the luminosity of the Sun^[1] from its photosphere at an effective temperature of 8,414 K.^[3] HD 27322 A is metal deficient with an iron abundance 56% that of the Sun's ([Fe/H] = −0.25)^[12] and it spins rapidly with a projected rotational velocity of 130 km/s.^[5]

The object was generally classified as a solitary star.^[15] However, evidence of HD 27322 being a binary first arose when an X-ray emission with a luminosity of 3.22×10²⁰ W was detected around the star.^[16] A-type stars are expected to be X-ray quiet, so it might be coming from a hidden companion. A 2016 spectroscopic survey detected a companion around HD 27322.^[9] It has 1.3 times the mass of the Sun and it has an effective temperature of 6,492 K.^[9] HD 27322 B is metal deficient with a [Fe/H] of −0.5 and it spins modestly with a projected rotational velocity of 20 km/s.^[9]

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. Oja, T. (August 1991). "UBV photometry of stars whose positions are accurately known. VI". Astronomy and Astrophysics Supplement Series. 89: 415. Bibcode:1991A&AS...89..415O. ISSN 0365-0138.
3. Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. eISSN 1432-0746. ISSN 0004-6361. S2CID 55586789.
4. Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright stars. I. A catalogue of spectral classifications". The Astronomical Journal. 74: 375. Bibcode:1969AJ.....74..375C. doi:10.1086/110819. ISSN 0004-6256. S2CID 121555804.
5. 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.
6. Guetter, H. H.; Hewitt, A. V. (1984). "Photoelectric UBV photometry for 317 PZT and VZT stars". Publications of the Astronomical Society of the Pacific. 96. IOP Publishing: 441. Bibcode:1984PASP...96..441G. doi:10.1086/131362. ISSN 0004-6280. S2CID 122222245.
7. 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.
8. 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.
9. Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (25 July 2016). "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars". The Astronomical Journal. 152 (2): 40. arXiv:1604.06456. Bibcode:2016AJ....152...40G. doi:10.3847/0004-6256/152/2/40. eISSN 1538-3881. S2CID 119179065.
10. 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.
11. David, Trevor J.; Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. eISSN 1538-4357. S2CID 33401607.
12. 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.
13. "HD 27322". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 17, 2023.
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. Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
16. Schröder, C.; Schmitt, J. H. M. M. (24 September 2007). "X-ray emission from A-type stars". Astronomy & Astrophysics. 475 (2): 677–684. Bibcode:2007A&A...475..677S. doi:10.1051/0004-6361:20077429. eISSN 1432-0746. ISSN 0004-6361. S2CID 120317590.