30 Piscium

30 Piscium (HIP 154) is a solitary[9] variable star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.37.[7] The distance to this star, based upon an annual parallax shift of 7.8859 mas, is around 410 light years. It is moving closer with a heliocentric radial velocity of −12 km/s.[6]

30 Piscium
Location of 30 Piscium (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pisces
Right ascension  00h 01m 57.61523s[1]
Declination −06° 00′ 50.6684″[1]
Apparent magnitude (V) 4.31 – 4.41[2]
Characteristics
Spectral type M3 III[3]
B−V color index 1.631±0.011[4]
Variable type LPV,[5] LB?[2]
Astrometry
Radial velocity (Rv)−11.7±0.5[6] km/s
Proper motion (μ) RA: +51.158[1] mas/yr
Dec.: −39.551[1] mas/yr
Parallax (π)7.8859 ± 0.4358[1] mas
Distance410 ± 20 ly
(127 ± 7 pc)
Absolute magnitude (MV)−1.20[5]
Details
Radius73.66+16.69
−6.79[1] R☉
Luminosity1,148.5±71.1[1] L☉
Surface gravity (log g)2[7] cgs
Temperature3,647[7] K
Other designations
30 Psc, YY Psc, BD−06° 6345, FK5 1630, HD 224935, HIP 154, HR 9089, SAO 147042[8]
Database references
SIMBADdata

This is an aging red giant star with a stellar classification of M3 III,[3] indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a candidate long-period variable star[5] and has been given the designation YY Psc.[10] Its varies in brightness between magnitudes 4.31 and 4.41 with no clear period. Possible periods of 23.1, 32.0, 53.6, and 167.8 days have been identified.[11] The star has 74 times the Sun's radius and is radiating 1,148.5[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,647 K.[7]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. 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. Bibcode:2009yCat....102025S.
  3. Keenan, P.; McNeil, R. (October 1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. 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.
  5. Rimoldini, L.; et al. (December 2012), "Automated classification of Hipparcos unsolved variables", Monthly Notices of the Royal Astronomical Society, 427 (4): 2917–2937, arXiv:1301.1545, Bibcode:2012MNRAS.427.2917R, doi:10.1111/j.1365-2966.2012.21752.x.
  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, A61.
  7. Pérez Martínez, M. I.; et al. (November 2014), "The non-active stellar chromosphere: Ca II basal flux", Monthly Notices of the Royal Astronomical Society, 445 (1): 270–279, Bibcode:2014MNRAS.445..270P, doi:10.1093/mnras/stu1706.
  8. "30 Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-03-10.
  9. 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.
  10. Kukarkin, B. V.; et al. (January 1975), "60th Name-List of Variable Stars", Information Bulletin on Variable Stars, 961: 1, Bibcode:1975IBVS..961....1K.
  11. Tabur, V; Bedding, T. R; Kiss, L. L; Moon, T. T; Szeidl, B; Kjeldsen, H (2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x.
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