Epoch J2000.0 Equinox J2000.0
|Right ascension||09h 47m 33.4904s|
|Declination||+11° 25′ 43.646″|
|Apparent magnitude (V)||4.4 - 11.3|
|Apparent magnitude (J)||-0.7|
|B−V color index||1.26|
(113.5  pc)
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 between 2,930 and 3,080 kelvins and radius spans between 320 and 350 solar radii (as large as 1.36–1.5 astronomical units, roughly Mars's orbital zone).
A planetary system?
In 2009 Wiesemeyer et al. 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 2.7–3 astronomical units. If confirmed such a planetary object could likely be an evaporating planet, with long comet-like trail as hinted by intense SiO maser emissions. Planetary temperature would exceed 1,500 kelvins, accounting a stellar luminosity of more than 8,000 times that of the Sun.
(in order from star)
|b (unconfirmed)||≥2 MJ||≥2.7||1898||0||—||—|
- "GCVS Query=R Leo". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22.
- "V* R Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-21.
- 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: . Bibcode:2009A&A...498..801W. doi:10.1051/0004-6361/200811242.
- Fedele; et al. (2005). "The K -Band Intensity Profile of R Leonis Probed by VLTI/VINCI". Astronomy and Astrophysics. 431 (3): 1019–1026. arXiv: . Bibcode:2005A&A...431.1019F. doi:10.1051/0004-6361:20042013.