Astronomy:V538 Carinae

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Short description: Variable star in the constellation Carina
V538 Carinae
V538CarLightCurve.png
A light curve for V538 Carinae, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Carina
Right ascension  11h 20m 06.2287s[2]
Declination −65° 15′ 07.134″[2]
Apparent magnitude (V) 7.7 - 9.2[3]
Characteristics
Evolutionary stage Red supergiant or AGB
Spectral type M3 II[4] or M3.8 Ib[5]
Variable type SRb[3]
Astrometry
Proper motion (μ) RA: −6.197[2] mas/yr
Dec.: 0.522[2] mas/yr
Parallax (π)0.1665 ± 0.0546[2] mas
Distanceapprox. 20,000 ly
(approx. 6,000 pc)
Details
Radius580[6][lower-alpha 1] - 2,264?[7] R
Luminosity30,600[6] L
Temperature3,302[2] K
Other designations
V538 Carinae, HD 98658, HIP 55355
Database references
SIMBADdata

V538 Carinae is a variable star in the constellation of Carina, and a possible red supergiant. If this star replaced the Sun in the Solar System, its photosphere would at least engulf the orbit of Mars.

Properties

V538 Carinae has a measured angular diameter of 3.4 mas.[8] Its distance is uncertain. At the Hipparcos distance of 1.33+5.81
−0.59
 kpc
, this corresponds to a radius of 580 R,[6] but at the distance implied by its Gaia Data Release 2 parallax, the radius would be around 1,900 R.[8] Calculations based on the Gaia DR2 parallax with temperatures and bolometric corrections inferred from Gaia colours give an even larger radius above 2,200 R.[7]

Some studies suggest that this star is a luminous AGB star and a long-period variable, instead of a supergiant.[9] It is classified in the General Catalogue of Variable Stars as a semiregular variable star of type SRb, indicating a cool pulsating giant star, with a possible period of 655 days. Its brightness varies between extremes of magnitude 7.7 and 9.2.[3]

Notes

  1. Applying the Stefan-Boltzmann Law with a nominal solar effective temperature of 5,772 K:
    [math]\displaystyle{ \sqrt{\left(\frac{5772}{3171}\right)^4\cdot 30,595.30}\approx579.55 \ R_\odot }[/math]

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 2.4 2.5 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.
  3. 3.0 3.1 3.2 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: B/gcvs. Bibcode2009yCat....102025S. 
  4. Pickles, A.; Depagne, É. (2010). "All-Sky Spectrally Matched UBVRI - ZY and u g r i z Magnitudes for Stars in the Tycho2 Catalog". Publications of the Astronomical Society of the Pacific 122 (898): 1437. doi:10.1086/657947. Bibcode2010PASP..122.1437P. 
  5. Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014) 1. Bibcode2014yCat....1.2023S. 
  6. 6.0 6.1 6.2 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society 427 (1): 343–57. doi:10.1111/j.1365-2966.2012.21873.x. Bibcode2012MNRAS.427..343M. 
  7. 7.0 7.1 Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; Lee, Nathan De; Collins, Kevin; Latham, David W. et al. (2019-09-09). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 1538-3881. Bibcode2019AJ....158..138S. 
  8. 8.0 8.1 Cruzalèbes, P.; Petrov, R. G.; Robbe-Dubois, S.; Varga, J.; Burtscher, L.; Allouche, F.; Berio, P.; Hofmann, K. H. et al. (2019). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society 490 (3): 3158–3176. doi:10.1093/mnras/stz2803. Bibcode2019MNRAS.490.3158C. 
  9. 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.