83 Leonis
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| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Leo |
| 83 Leonis A | |
| Right ascension | 11h 26m 45.32s |
| Declination | +3° 0′ 47.18″ |
| Apparent magnitude (V) | 6.49 |
| 83 Leonis B | |
| Right ascension | 11h 26m 46.2771s |
| Declination | +03° 00′ 22.781″ |
| Apparent magnitude (V) | 7.57 |
| Characteristics | |
| Spectral type | K0IV / K2V |
| Variable type | None |
| Astrometry | |
| Distance | 57.61 ly (17.67 pc) |
| Details | |
| Mass | ? / 0.78 M☉ |
| Radius | 1.9 / 0.81 R☉ |
| Luminosity | 66 / L☉ |
| Temperature | 5509 ± 8.6 [1] / 4875 K |
| Metallicity | 1.2 / 0.36 |
| Age | ? / 4.49 billion years |
| Other designations | |
|
Wolf 393, GJ 429, HD 99491/2, BD+03°2502/3, HIP 55846, HR 4414
|
|
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
83 Leonis, abbreviated 83 Leo, is a binary star system approximately 58 light-years away in the constellation of Leo (the Lion). The primary star of the system is a cool orange subgiant star, while the secondary star is an orange dwarf star. The two stars are separated by at least 515 astronomical units away from each other. Both stars are presumed to be cooler than the Sun.
As of 2005, an extrasolar planet[2] has been confirmed to be orbiting the secondary star within the system. Because of the optical component of the two stars (which appears close to the stars because of our line-of-sight), this planet was able to be discovered.
Contents |
[edit] Stellar system
The primary component, 83 Leonis A, is a 6th magnitude star. It is not visible to the unaided eye, but easily visible with small binoculars. The star is classified as a subgiant, meaning that it has ceased fusing hydrogen in its core and started to evolve towards red gianthood.
The secondary component, 83 Leonis B, is an 8th magnitude orange dwarf, somewhat less massive (0.88 MSun), smaller and cooler than our Sun. [3] It is visible only with binoculars or better equipment. Components A and B share common proper motion, which confirms them as a physical pair. The projected separation between the stars is 515 AU, but the true separation may be much higher. [4]
There is yet another, magnitude 14.4 component listed in the Washington Double Star Catalog. However, this star is moving into a different direction and is therefore not a true member of the 83 Leonis system.
[edit] Planetary system
Planet 83 Leonis Bb was discovered in Jan 2005 by the California and Carnegie Planet Search team, who use the radial velocity method to detect planets. It is one of the smallest planets detected so far, having mass less than half that of Saturn. It orbits in a circular but a very close orbit around the star, completing one orbit in about 17 days.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | ≥ 0.109 ± 0.013 MJ | 0.1232 ± 0.0071 | 17.0431 ± 0.047 | 0.254 ± 0.092 |
[edit] See also
[edit] References
- ^ Kovtyukh et al. (2003). "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios". Astronomy and Astrophysics 411 (3): 559–564. doi:. http://www.aanda.org/articles/aa/full/2003/46/aa3944/aa3944.html.
- ^ Marcy et al. (2005). "Five New Extrasolar Planets". The Astrophysical Journal 619 (1): 570–584. doi:. http://www.iop.org/EJ/article/0004-637X/619/1/570/60844.html.
- ^ "The Planet Around HD 99492". California & Carnegie Planet Search. http://exoplanets.org/esp/hd99492/hd99492.shtml. Retrieved 2006-05-09.
- ^ Raghavan et al. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems". The Astrophysical Journal 646 (1): 523–542. doi:. http://www.iop.org/EJ/article/0004-637X/646/1/523/64035.html.
- ^ Butler et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. doi:. http://www.iop.org/EJ/article/0004-637X/646/1/505/64046.html.
[edit] External links
- "83 Leonis AB". SolStation. http://www.solstation.com/stars2/83leo2.htm. Retrieved 2008-06-20.
- "Notes for star HD 99492". The Extrasolar Planets Encyclopaedia. http://exoplanet.eu/star.php?st=HD+99492. Retrieved 2008-06-20.
Coordinates: 
11h 26m 45.32s, +03° 00′ 47.18″
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