HD 3322

HD 3322 is a binary star[7] system in the northern constellation of Andromeda. With an apparent visual magnitude of 6.51,[2] it lies below the nominal brightness limit for visibility with the normal naked eye, but it is still possible to see the star with excellent vision under ideal seeing conditions. An annual parallax shift of 4.59±0.65 mas[1] provides a distance estimate of roughly 700 light years.

HD 3322
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 36m 20.09863s[1]
Declination +27° 15′ 17.1519″[1]
Apparent magnitude (V) 6.51[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type B8.5 IIIp HgMn[4]
B−V color index −0.070±0.011[2]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)+4.0±7.4[6] km/s
Proper motion (μ) RA: +15.96[1] mas/yr
Dec.: −11.11[1] mas/yr
Parallax (π)4.59 ± 0.65 mas[1]
Distanceapprox. 700 ly
(approx. 220 pc)
Absolute magnitude (MV)−0.13[2]
Orbit[7]
Period (P)399.6±2.1 d
Eccentricity (e)0.57±0.09
Periastron epoch (T)2440462.38 ± 6.05 JD
Argument of periastron (ω)
(secondary)		304±11°
Semi-amplitude (K1)
(primary)		8.07±1.07 km/s
Details
HD 3322 A
Mass3.68±0.21[3] M☉
Radius4.8[8] R☉
Luminosity246+91
−66[3] L☉
Surface gravity (log g)3.821±0.056[9] cgs
Temperature12,882+90
−88[3] K
Rotational velocity (v sin i)14[3] km/s
Other designations
PY And, BD+26° 91, HD 3322, HIP 2865, HR 149, SAO 74136[10]
Database references
SIMBADdata

This is a single-lined spectroscopic binary star system with an orbital period of around 400 days and an eccentricity of 0.57.[7] The visible component has a stellar classification of B8.5 IIIp HgMn,[4] matching a chemically peculiar B-type giant mercury-manganese star.[11] Catalano and Leone (1991) found it to be a α2 CVn variable with a period of 4.6904 days,[12] and thus it received the variable star designation PY And.[5] It has an estimated 3.7[3] times the mass of the Sun and about 4.8[8] times the Sun's radius. It is radiating around 246[3] times the Sun's luminosity from its photosphere at an effective temperature of 12,882 K.[3]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  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, S2CID 119257644.
  3. Zorec, J.; Royer, F. (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, S2CID 55586789.
  4. Abt, Helmut A.; Morrell, Nidia I. (July 1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
  5. Kazarovets, E. V.; et al. (February 1993), "The 71st Name-List of Variable Stars", Information Bulletin on Variable Stars, 3840: 1, Bibcode:1993IBVS.3840....1K.
  6. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  7. Stickland, D. J.; Weatherby, J. (1984), "Radial velocities of northern Mercury stars", Astronomy and Astrophysics Supplement Series, 57: 55–67, Bibcode:1984A&AS...57...55S.
  8. "HIP 2865", Wolfram Alpha, retrieved 2013-08-09
  9. Huang, Wenjin; et al. (October 2010), "A Stellar Rotation Census of B Stars: From ZAMS to TAMS", The Astrophysical Journal, 722 (1): 605–619, arXiv:1008.1761, Bibcode:2010ApJ...722..605H, doi:10.1088/0004-637X/722/1/605, S2CID 118532653.
  10. "V* PY And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-05-01.
  11. Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.
  12. Catalano, F. A.; Leone, F. (April 1991), "Photoelectric photometry of chemically peculiar stars at the Catania Astrophysical Observatory. II - Observations of the CP3 stars HD 3322, HD 27295 and HD 89822", Astronomy and Astrophysics, 244 (2): 327–334, Bibcode:1991A&A...244..327C.
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