63 Andromedae

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63 Andromedae (abbreviated 63 And) is an Alpha2 Canum Venaticorum (α2 CVn) variable star in the constellation Andromeda. Its variable star designation is PZ Andromedae. With an apparent magnitude of about 5.6, it is bright enough to be seen by naked eye. Based upon an annual parallax shift of 8.53 mas, it is located 382 light years away.

63 Andromedae
Location of 63 Andromedae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 02h 20m 58.202s[1]
Declination +50° 09′ 05.39″[1]
Apparent magnitude (V) 5.59[2]
Characteristics
Spectral type B9VpSi[3]
B−V color index −0.089[4]
Variable type α2 CVn[2]
Astrometry
Radial velocity (Rv)−0.30[5] km/s
Proper motion (μ) RA: 39.818[1] mas/yr
Dec.: −31.607[1] mas/yr
Parallax (π)8.5275 ± 0.1684 mas[1]
Distance382 ± 8 ly
(117 ± 2 pc)
Absolute magnitude (MV)+0.26[6]
Details[6]
Mass3.07±0.14 M
Radius2.4±0.3 R
Luminosity110 L
Surface gravity (log g)4.29±0.11 cgs
Temperature11,967 K
Rotation4.189 days
Other designations
PZ And, BD+49 640, HD 14392, HIP 10944, HR 682, NSV 790, SAO 37960, PPM 27476
Database references
SIMBADdata

The spectral type of this star is B9VpSi, indicating that it is a chemically peculiar main sequence star with abnormally strong silicon lines. Although it has a B-type spectral class, this type of star is known as an Ap star, a class of stars with very strong spectral lines of certain heavy elements and strong magnetic fields. The chemical peculiarities are caused by stratification in the atmosphere due to slow rotation.[7]

The star has 3 times the mass of the Sun and 2.4 times the Sun's radius. It is radiating 110 times the Sun's luminosity from its photosphere at an effective temperature of 11,967 K.[6]

A light curve for PZ Andromedae, plotted from TESS data[8]

63 Andromedae varies in brightness by about 0.05 magnitudes with a period of 4.189 days. This is believed to occur as it rotates. This type of variable star is known as an α2 Canum Venaticorum variable after the first example to be studied.[2]

To the naked eye the star figures as a faint, dense asterism with 64 and 65 Andromedae (southwest and west), which together justify a rectangular projection (extreme) of the constellation (official boundaries).[9] North, west and east are an arm/hand, fictitiously and geometrically, of Perseus, whose character is related in traditional mythology as Andromeda's saviour, saving her from the sea monster, who forever retreats to beyond Pisces, Cetus. The closest star in the asterisms commonly drawn up to represent the princess herself is 51 Andromedae, to the east. At an apparent magnitude of 3.57, this star shines two magnitudes or 6.3 times brighter.[9]

References

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  1. ^ a b c d e 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. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  3. ^ Abt, H. A.; Morrell, N. 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.
  4. ^ 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.Vizier catalog entry
  5. ^ 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.
  6. ^ a b c North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286, Bibcode:1998A&A...334..181N
  7. ^ Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics. 498 (3): 961. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788.
  8. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  9. ^ a b "Constellations.gif". Retrieved July 7, 2022.
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