Astronomy:HD 27322

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Short description: A-type dwarf; Camelopardalis
HD 27322
Camelopardalis constellation map.svg
Red circle.svg
Location of HD 27322 on the map (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
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[1] mas/yr
Dec.: +7.466[1] mas/yr
Parallax (π)10.4168 ± 0.0907 mas
Distance313 ± 3 ly
(96.0 ± 0.8 pc)
Absolute magnitude (MV)+0.98[8]
Details
A
Mass1.9±0.1[9] M☉
Radius2.64+0.11−0.10[10] R☉
Luminosity54.7+1.0−0.9[1] L☉
Surface gravity (log g)3.88±0.14[11] cgs
Temperature8,414+176−173[3] K
Metallicity [Fe/H]−0.25[12] dex
Rotational velocity (v sin i)130±8[5] km/s
Age640[11] Myr
B
Mass1.30±0.04[9] M☉
Temperature6,492±109[9] K
Rotational velocity (v sin i)20[9] km/s
Other designations
BD+56°509, GC 5253, HD 27322, HIP 20380, HR 1342, SAO 24563[13]
Database references
SIMBADdata

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 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. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 Oja, T. (August 1991). "UBV photometry of stars whose positions are accurately known. VI.". Astronomy and Astrophysics Supplement Series 89: 415. ISSN 0365-0138. Bibcode: 1991A&AS...89..415O. 
  3. ↑ 3.0 3.1 3.2 3.3 Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. Bibcode: 2012A&A...537A.120Z. 
  4. ↑ 4.0 4.1 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. doi:10.1086/110819. ISSN 0004-6256. Bibcode: 1969AJ.....74..375C. 
  5. ↑ 5.0 5.1 5.2 5.3 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. doi:10.1086/192182. ISSN 0067-0049. Bibcode: 1995ApJS...99..135A. 
  6. ↑ 6.0 6.1 Guetter, H. H.; Hewitt, A. V. (1984). "Photoelectric UBV photometry for 317 PZT and VZT stars". Publications of the Astronomical Society of the Pacific (IOP Publishing) 96: 441. doi:10.1086/131362. ISSN 0004-6280. Bibcode: 1984PASP...96..441G. 
  7. ↑ 7.0 7.1 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. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G. 
  8. ↑ 8.0 8.1 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 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. doi:10.3847/0004-6256/152/2/40. Bibcode: 2016AJ....152...40G. 
  10. ↑ 10.0 10.1 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S. 
  11. ↑ 11.0 11.1 11.2 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. doi:10.1088/0004-637X/804/2/146. Bibcode: 2015ApJ...804..146D. 
  12. ↑ 12.0 12.1 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. 
  13. ↑ "HD 27322". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+27322. 
  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. doi:10.1093/mnras/stx2219. ISSN 0035-8711. Bibcode: 2017MNRAS.472.3805G. 
  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. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode: 2008MNRAS.389..869E. 
  16. ↑ Schröder, C.; Schmitt, J. H. M. M. (24 September 2007). "X-ray emission from A-type stars". Astronomy & Astrophysics 475 (2): 677–684. doi:10.1051/0004-6361:20077429. ISSN 0004-6361. Bibcode: 2007A&A...475..677S. 



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