Astronomy:56 Leonis

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Short description: Variable star in the constellation Leo
56 Leonis
Leo constellation map.svg
Red circle.svg
Location of 56 Leonis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Leo
Right ascension  10h 56m 01.4690s[1]
Declination +06° 11′ 07.328″[1]
Apparent magnitude (V) 5.69 – 6.03[2]
Characteristics
Evolutionary stage red giant[3]
Spectral type M5.5III[2]
Variable type LB?[2]
Astrometry
Proper motion (μ) RA: −23.90[1] mas/yr
Dec.: −6.42[1] mas/yr
Parallax (π)8.39 ± 0.37[1] mas
Distance390 ± 20 ly
(119 ± 5 pc)
Details
Mass1.1[4] M
Radius192[5] R
Luminosity1,479[6] L
Surface gravity (log g)0.64[6] cgs
Temperature3,279[6] K
Metallicity [Fe/H]+0.45[4] dex
Other designations
Database references
SIMBADdata

56 Leonis is a red giant variable star located approximately 390 light years away in the constellation Leo.

A light curve for VY Leonis, plotted from Hipparcos data[7]

The apparent magnitude of 56 Leonis varies between 5.69 and 6.03, making it dimly visible to the naked eye, and it has been given the variable star designation VY Leo. The type of variability is uncertain. The General Catalogue of Variable Stars suggests it may be a slow irregular variable, but some sources have found periods and report it as semiregular.[8]

The spectral class of 56 Leonis is M5.5III, indicating a cool red giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence. It is undecided whether it is currently on the red giant branch or asymptotic giant branch.[3] The star has an estimated 1.1[4] times the mass of the Sun but has expanded to 192 times the Sun's radius.[5] The star is radiating 1,479[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,279 K.[6]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Samus, N. N. et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1 61 (1): 80–88. doi:10.1134/S1063772917010085. Bibcode2017ARep...61...80S. 
  3. 3.0 3.1 McDonald, I.; De Beck, E.; Zijlstra, A. A.; Lagadec, E. (2018). "Pulsation-triggered dust production by asymptotic giant branch stars". Monthly Notices of the Royal Astronomical Society 481 (4): 4984. doi:10.1093/mnras/sty2607. Bibcode2018MNRAS.481.4984M. 
  4. 4.0 4.1 4.2 Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A. et al. (2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. Bibcode2019A&A...628A..94A. 
  5. 5.0 5.1 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3. Proper-motion anomaly and resolved common proper-motion pairs". Astronomy and Astrophysics 657: 657. doi:10.1051/0004-6361/202142146. Bibcode2022A&A...657A...7K. 
  6. 6.0 6.1 6.2 6.3 6.4 Lebzelter, Thomas; Hinkle, Kenneth H.; Straniero, Oscar; Lambert, David L.; Pilachowski, Catherine A.; Nault, Kristie A. (2019). "Carbon and Oxygen Isotopic Ratios. II. Semiregular Variable M Giants". The Astrophysical Journal 886 (2): 117. doi:10.3847/1538-4357/ab4e9b. Bibcode2019ApJ...886..117L. 
  7. "Light Curve". ESA. https://www.cosmos.esa.int/web/hipparcos/java-tools/light-curve. 
  8. "VY Leonis". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=17074.