Mu Pictoris

μ Pictoris, Latinised as Mu Pictoris, is a binary star[3] system in the southern constellation Pictor. It is bright enough to be dimly visible to the naked eye, having a combined apparent visual magnitude of 5.69.[2] Based upon an annual parallax shift of 4.31 mas as seen from Earth,[1] the system is located roughly 760 light years distant from the Sun. As of 2010, the pair have an angular separation of 2.46 arc seconds along a position angle of 221°.[4]

Mu Pictoris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pictor
Right ascension 06h 31m 58.31021s[1]
Declination −58° 45′ 13.8117″[1]
Apparent magnitude (V) 5.69[2] (5.71 + 9.43)[3]
Characteristics
Spectral type B9 Ve[4] or B9 IVn + A8 V:p?[5]
U−B color index −0.17[2]
B−V color index −0.06[2]
Astrometry
Radial velocity (Rv)+0.40±1.00[6] km/s
Proper motion (μ) RA: −1.34[1] mas/yr
Dec.: +1.77[1] mas/yr
Parallax (π)4.31 ± 0.38[1] mas
Distance760 ± 70 ly
(230 ± 20 pc)
Absolute magnitude (MV)0.20/3.75[7]
Details
μ Pic A
Mass3.60±0.09[8] M☉
Luminosity355[8] L☉
Temperature10,568[8] K
Rotational velocity (v sin i)228[8] km/s
Other designations
μ Pic, CPD−58° 722, HD 46860, HIP 31137, HR 2412, SAO 234564[9]
Database references
SIMBADdata

The primary, designated component A, is a blue-white star with a visual magnitude of 5.71[3] and a stellar classification of B9 Ve[4] or B9 IVn.[5] The first classification suggests is a B-type main-sequence star, with the 'e' suffix indicating a Be star. The second may instead indicate a somewhat more evolved B-type star that is spinning rapidly, resulting in "nebulous" absorption lines. Photometrically, it shows a pulsation period of 0.397 days, which is likely the same as the rotation period.[10]

The secondary companion, component B, is a white-hued star of magnitude 9.43[3] with a classification of A8 V:p?.[5] This indicates it is an A-type main-sequence star, with the 'p?' suffix suggesting it may be chemically peculiar while the ':' notation says there is some uncertainty about the general classification.

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. Hurly, P. R. (1975), "Combined-light UBV Photometry of 103 Bright Southern Visual Doubles", Monthly Notes of the Astronomical Society of Southern Africa, 34: 7, Bibcode:1975MNSSA..34....7H.
  3. Eggleton, P. P.; Tokovinin, A. A. (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, S2CID 14878976.
  4. Oudmaijer, René D.; Parr, Andrew M. (July 2010), "The binary fraction and mass ratio of Be and B stars: a comparative Very Large Telescope/NACO study", Monthly Notices of the Royal Astronomical Society, 405 (4): 2439–2446, arXiv:1003.0618, Bibcode:2010MNRAS.405.2439O, doi:10.1111/j.1365-2966.2010.16609.x, S2CID 119209332.
  5. Corbally, C. J. (1984), "Close visual binaries. I - MK classifications", Astrophysical Journal Supplement Series, 55: 657, Bibcode:1984ApJS...55..657C, doi:10.1086/190973.
  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. Corbally, C. J. (December 1984), "Close visual binaries. III - Parameters and evolutionary status", Astronomical Journal, 89: 1887–1896, Bibcode:1984AJ.....89.1887C, doi:10.1086/113700.
  8. 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, S2CID 55586789.
  9. "mu. Pic". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-08.
  10. Balona, L. A. (December 1995), "Tests of the Pulsation and Starspot Models for the Periodic Be-Stars", Monthly Notices of the Royal Astronomical Society, 277 (4): 1547, Bibcode:1995MNRAS.277.1547B, doi:10.1093/mnras/277.4.1547.
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