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R Leonis
Location of R Leonis (circled)
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Leo
Right ascension 09h 47m 33.4840s [1]
Declination +11° 25′ 43.823″ [1]
Apparent magnitude (V) 4.4 - 11.3 [2]
Characteristics
Spectral type M6e-M8IIIe-M9.5e [2]
Apparent magnitude ( J) −0.7 [3]
B−V color index 1.26
Variable type Mira
Astrometry
Proper motion (μ) RA: 6.132 [1]  mas/ yr
Dec.: −53.097 [1]  mas/ yr
Parallax (π)14.0566 ± 0.8378  mas [1]
Distance372  ly
(114 [4]  pc)
Details
Mass0.7 [5]  M☉
Radius299, [6] 320-350 [7]  R☉
Luminosity3,537 [4]  L☉
Temperature2,890 [6] (2,930 - 3,080) [7]  K
Other designations
R Leo, HIP 48036, HD 84748, HR 3882, BD+12°2096, SAO 98769
Database references
SIMBAD data

R Leonis is a red giant Mira-type variable star located approximately 370 light years away in the constellation Leo.

The light curve of R Leonis from AAVSO V band data [8]

The apparent magnitude of R Leonis varies between 4.31 and 11.65 with a period of 312 days. At maximum it can be seen with the naked eye, while at minimum a telescope of at least 7 cm is needed. The star's effective temperature is estimated 2,890 kelvins and radius spans 299 solar radii (208,000,000 kilometres; 1.39 astronomical units), [6] roughly Mars's orbital zone.

Possible planet

Artistic rendering of R Leonis's putative evaporating planetary companion

In 2009 Wiesemeyer et al. [5] proposed that quasi-periodic fluctuations observed for the star R Leonis may be due to the presence of an evaporating substellar companion, probably an extrasolar planet. They have inferred a putative mass for the orbiting body of twice the mass of Jupiter, orbital period of 5.2 years and likely orbital separation of 2.7 astronomical units. If confirmed such a planetary object could likely be an evaporating planet, with a long comet-like trail as hinted by intense SiO maser emissions.

The R Leonis planetary system
Companion
(in order from star) 		Mass Semimajor axis
( AU) 		Orbital period
( days) 		Eccentricity Inclination Radius
b (unconfirmed) ≥2 MJ ≥2.7 1898 0 — —

References

  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b "GCVS Query=R Leo". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22.
  3. ^ "V* R Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-21.
  4. ^ a b 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. arXiv: 1809.07965. Bibcode: 2018MNRAS.481.4984M. doi: 10.1093/mnras/sty2607. S2CID  118969263.
  5. ^ a b Wiesemeyer; et al. (2009). "Precessing planetary magnetospheres in SiO stars?. First detection of quasi-periodic polarization fluctuations in R Leonis and V Camelopardalis". Astronomy and Astrophysics. 498 (3): 801–810. arXiv: 0809.0359. Bibcode: 2009A&A...498..801W. doi: 10.1051/0004-6361/200811242. S2CID  14531031.
  6. ^ a b c De Beck, E.; Decin, L.; De Koter, A.; Justtanont, K.; Verhoelst, T.; Kemper, F.; Menten, K. M. (2010). "Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae". Astronomy and Astrophysics. 523: A18. arXiv: 1008.1083. Bibcode: 2010A&A...523A..18D. doi: 10.1051/0004-6361/200913771. S2CID  16131273.
  7. ^ a b Fedele; et al. (2005). "The K -Band Intensity Profile of R Leonis Probed by VLTI/VINCI". Astronomy and Astrophysics. 431 (3): 1019–1026. arXiv: astro-ph/0411133. Bibcode: 2005A&A...431.1019F. doi: 10.1051/0004-6361:20042013. S2CID  15500217.
  8. ^ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.

External links

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