Y Carinae

Y Carinae (Y Car) is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

This article is about the variable star. For y Carinae, see V533 Carinae.
Y Carinae
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension  10h 33m 10.85133s[1]
Declination −58° 29′ 55.0959″[1]
Apparent magnitude (V) 8.16[2] (7.53 - 8.48[3])
Characteristics
Spectral type F2 + B9.0V[4]
B−V color index +0.59[2]
Variable type Classical Cepheid[3]
Astrometry
Radial velocity (Rv)−12.90[5] km/s
Proper motion (μ) RA: −5.83[1] mas/yr
Dec.: 3.21[1] mas/yr
Parallax (π)1.07 ± 1.10[1] mas
Absolute magnitude (MV)−3.0[6]
Orbit[6]
PrimaryA
CompanionB
Period (P)1006.9 days
Eccentricity (e)0.437
Semi-amplitude (K1)
(primary)		10.0 km/s
Details
A
Mass3.8[6] M☉
Luminosity1,250[6] L☉
Surface gravity (log g)1.800[2] cgs
Temperature5,800[6] K
Metallicity−0.230[2]
Other designations
Y Carinae, Y Car, CD−57°3305, GSC 08613-01464, HD 91595, HIP 51653, 2MASS J10331084-5829550, SAO 238178
Database references
SIMBADdata

The primary Cepheid pulsation period is 3.6 days, but it also pulsates with a secondary period of 2.56 days. It is known as a double-mode Cepheid, or a beat Cepheid since the two periods interfere to produce slow variations at a beat frequency.[6]

The variable primary star is in a triple system with a very close pair of hot main sequence stars. The period of the outer pair is 2.76 years. The inner pair are constrained to orbit in less than 31 days, but the exact nature of the orbit is unknown. The existence of the close binary pair throws into doubt previous calculations of the mass of the pulsating star. The existence of high numbers of triple systems and short period Cepheids suggests that some at least of the short period Cepheids may have formed by mergers.[7]

References
  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. Soubiran, C.; Le Campion, J.-F.; Cayrel De Strobel, G.; Caillo, A. (2010). "The PASTEL catalogue of stellar parameters". Astronomy and Astrophysics. 515: A111. arXiv:1004.1069. Bibcode:2010A&A...515A.111S. doi:10.1051/0004-6361/201014247.
  3. 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.
  4. Zhou, A.-Y. (2010). "Pulsating Components in Binary and Multiple Stellar Systems --- A Catalog of Oscillating Binaries". arXiv:1002.2729 [astro-ph.SR].
  5. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213.
  6. Bohm-Vitense, E.; Evans, N. R.; Carpenter, K.; Morgan, S.; Beck-Winchatz, B.; Robinson, R. (1997). "The dynamical mass of the beat cepheid Y carinae and stellar opacities". The Astronomical Journal. 114: 1176. Bibcode:1997AJ....114.1176B. doi:10.1086/118549.
  7. Evans, Nancy Remage; Carpenter, Kenneth G.; Robinson, Richard; Kienzle, Francesco; Dekas, Anne E. (2005). "High-Mass Triple Systems: The Classical Cepheid Y Carinae". The Astronomical Journal. 130 (2): 789. arXiv:astro-ph/0504169. Bibcode:2005AJ....130..789E. doi:10.1086/430458.
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