Y Lyncis

Y Lyncis is a semiregular variable star in the constellation Lynx. It is an asymptotic giant branch star of spectral type M6S, with a luminosity class of Ib, indicating a supergiant luminosity. It is around 800 light years away.

Y Lyncis
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 07h 28m 11.61802s[1]
Declination +45° 59′ 26.2366″[1]
Apparent magnitude (V) 6.2 - 8.9[2]
Characteristics
Spectral type M6S Ib[3]
Variable type SRc[3]
Astrometry
Radial velocity (Rv)5.50 ± 0.6 km/s
Proper motion (μ) RA: 0.23 ± 1.17[1] mas/yr
Dec.: −3.41 ± 0.60[1] mas/yr
Parallax (π)3.95 ± 0.95[1] mas
Distanceapprox. 800 ly
(approx. 250 pc)
Details
Mass1.5 - 2.0[2] M☉
Radius580[2] R☉
Luminosity10,765[4] L☉
Surface gravity (log g)0.0[5] cgs
Temperature3,200[5] K
Metallicity [Fe/H]−0.19[5] dex
Other designations
Y Lyn, HD 58521, BD+46° 1271, HIP 36288, SAO 41784
Database references
SIMBADdata

Y Lyncis ranges in brightness from magnitude 6.8 to 8.9. Its changes in brightness are complex with at least two different periods showing. The General Catalogue of Variable Stars lists a period of 110 days.[6] More recent studies show a primary pulsation period of 133 days, with and a long secondary period with an amplitude of 0.2 magnitudes and duration 1,300 days. The long secondary period variations are possibly caused by long-lived convection cells.[7]

Y Lyncis has a mass around 1.5-2.0 M☉ and a luminosity around 10,000 L☉. It is a thermally pulsing asymptotic giant branch star, an evolved star with a carbon-oxygen core that is fusing helium in a shell and hydrogen in a separate shell.[8] It is also an S-type star, where third dredge-ups have brought some carbon to the surface, but not enough to create a carbon star.[4]

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. Szatmary, Karoly; Vinko, Jozsef (1992). "Periodicities of the light curve of the semiregular variable star Y Lyncis". Monthly Notices of the Royal Astronomical Society. 256 (2): 321–28. Bibcode:1992MNRAS.256..321S. doi:10.1093/mnras/256.2.321.
  3. Kiss, L. L.; Szabó, Gy. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society. 372 (4): 1721–1734. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x. S2CID 5203133.
  4. Guandalini, R.; Busso, M. (2008). "Infrared photometry and evolution of mass-losing AGB stars. II. Luminosity and colors of MS and S stars". Astronomy and Astrophysics. 488 (2): 675–684. arXiv:0806.4591. Bibcode:2008A&A...488..675G. doi:10.1051/0004-6361:200809932. S2CID 14294870.
  5. Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
  6. 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.
  7. Percy, John R.; Sato, Hiromitsu (2009). "Long Secondary Periods in Pulsating Red Supergiant Stars". Journal of the Royal Astronomical Society of Canada. 103 (1): 11. Bibcode:2009JRASC.103...11P.
  8. Guandalini, R.; Busso, M. (2008). "Infrared photometry and evolution of mass-losing AGB stars". Astronomy and Astrophysics. 488 (2): 675–684. arXiv:0806.4591. Bibcode:2008A&A...488..675G. doi:10.1051/0004-6361:200809932. S2CID 14294870.
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