Astronomy:Y Carinae

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Short description: Star in the constellation Carina
Y Carinae
YCarLightCurve.png
A light curve for Y Carinae, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Carina
Right ascension  10h 33m 10.85133s[2]
Declination −58° 29′ 55.0959″[2]
Apparent magnitude (V) 8.16[3] (7.53 – 8.48[4])
Characteristics
Spectral type F0/3[5] + B9V[6]
B−V color index +0.59[3]
Variable type Classical Cepheid[4]
Astrometry
Radial velocity (Rv)−12.90[7] km/s
Proper motion (μ) RA: −5.83[2] mas/yr
Dec.: 3.21[2] mas/yr
Parallax (π)0.3011 ± 0.0358[8] mas
Distanceapprox. 11,000 ly
(approx. 3,300 pc)
Absolute magnitude (MV)−3.0[9]
Orbit[9]
PrimaryA
CompanionB
Period (P)1006.9 days
Eccentricity (e)0.437
Semi-amplitude (K1)
(primary)
10.0 km/s
Details
A
Mass4.9[10] M
Luminosity1,250[9] L
Surface gravity (log g)1.800[3] cgs
Temperature5,800[9] K
Metallicity−0.230[3]
Other designations
Y Carinae, Y Car, CD−57°3305, GSC 08613-01464, HD 91595, HIP 51653, 2MASS J10331084-5829550, SAO 238178, Gaia DR2 5351428787262634624
Database references
SIMBADdata

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.

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.[9]

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.[11]

References

  1. "Hipparcos Tools Interactive Data Access". ESA. https://www.cosmos.esa.int/web/hipparcos/interactive-data-access. 
  2. 2.0 2.1 2.2 2.3 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V. 
  3. 3.0 3.1 3.2 3.3 Soubiran, C.; Le Campion, J.-F.; Cayrel De Strobel, G.; Caillo, A. (2010). "The PASTEL catalogue of stellar parameters". Astronomy and Astrophysics 515: A111. doi:10.1051/0004-6361/201014247. Bibcode2010A&A...515A.111S. 
  4. 4.0 4.1 Samus, N. N. 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. Bibcode2009yCat....102025S. 
  5. Houk, Nancy (1975). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode1975MSS...C01....0H. 
  6. Evans, Nancy R. (1992). "The Luminosity of the Double-Mode Cepheid y Carinae". The Astrophysical Journal 385: 680. doi:10.1086/170974. Bibcode1992ApJ...385..680E. 
  7. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G. et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics 424 (2): 727–732. doi:10.1051/0004-6361:20041213. Bibcode2004A&A...424..727P. 
  8. Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  9. 9.0 9.1 9.2 9.3 9.4 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. doi:10.1086/118549. Bibcode1997AJ....114.1176B. 
  10. Evans, Nancy Remage; Berdnikov, Leonid; Lauer, Jennifer; Morgan, Douglas; Nichols, Joy; Günther, H. Moritz; Gorynya, Natalya; Rastorguev, Alexey et al. (2015). "Binary Properties from Cepheid Radial Velocities (CRaV)". The Astronomical Journal 150 (1): 13. doi:10.1088/0004-6256/150/1/13. Bibcode2015AJ....150...13E. 
  11. 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): 789–793. doi:10.1086/430458. Bibcode2005AJ....130..789E.