Astronomy:R Leonis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas |
| Distance | 372 ly (114[4] pc) |
| Details | |
| Mass | 0.7[5] M☉ |
| Radius | 299,[6] 320-350[7] R☉ |
| Luminosity | 3,537[4] L☉ |
| Temperature | 2,890[6] (2,930 - 3,080)[7] K |
| Other designations | |
| 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 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
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.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥2 MJ | ≥2.7 | 1898 | 0 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 "GCVS Query=R Leo". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=R+Leo. Retrieved 2012-08-22.
- ↑ "V* R Leo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+R+Leo.
- ↑ 4.0 4.1 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. Bibcode: 2018MNRAS.481.4984M.
- ↑ 5.0 5.1 Wiesemeyer (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. doi:10.1051/0004-6361/200811242. Bibcode: 2009A&A...498..801W.
- ↑ 6.0 6.1 6.2 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. doi:10.1051/0004-6361/200913771. Bibcode: 2010A&A...523A..18D.
- ↑ 7.0 7.1 Fedele (2005). "The K -Band Intensity Profile of R Leonis Probed by VLTI/VINCI". Astronomy and Astrophysics 431 (3): 1019–1026. doi:10.1051/0004-6361:20042013. Bibcode: 2005A&A...431.1019F.
- ↑ "Download Data". AAVSO. https://www.aavso.org/data-download.
External links
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