83 Leonis
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83 Leonis (abbreviated 83 Leo) is a wide binary star system in the constellation Leo. It consists of two orange stars cooler than our Sun. The primary is an orange subgiant star, and the secondary is an orange dwarf star. The two stars are separated by at least 515 AU.
In 2005 a planet[1] was announced orbiting the secondary star. There is also an optical component which appears close to the stars because of our line-of-sight.
Contents |
[edit] The system
| Observation data Epoch 2000 |
|
|---|---|
| Constellation (pronunciation) |
Leo |
| Right ascension | 11h 26m 45.32s 11h 26m 46.28s |
| Declination | +3° 0' 47.18" +3° 0' 22.78" |
| Apparent magnitude (V) | 6.49/7.57 |
| Distance | 57.61/58.64 ly (17.67/17.99 pc) |
| Spectral type | K0IV/K2V |
| Other designations | |
|
Wolf 393, GJ 429, HD 99491/2, BD+03°2502/3, HIP 55846, HR 4414
|
|
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. [2] 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. [3]
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] The planet
| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| Orbital elements | ||
| Semimajor axis | (a) | 0.1232±0.0071 AU |
| Eccentricity | (e) | 0.254±0.092 |
| Orbital period | (P) | 17.0431±0.047 d |
| Angular distance | (θ) | 6.844 mas |
| Longitude of periastron |
(ω) | 219±22° |
| Time of periastron | (T0) | 2,450,468.7±1.4 JD |
| Semi-amplitude | (K) | 9.8±1.0 m/s |
| Physical characteristics | ||
| Mass | (m) | >0.109±0.013 MJ |
| Discovery information | ||
| Discovery date | Jan 25, 2005 | |
| Discoverer(s) | Marcy, Butler, Vogt et al. |
|
| Detection method | Radial velocity | |
| Discovery status | Published | |
83 Leonis Bb is an extrasolar planet orbiting the secondary star. The planet 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.
[edit] External links
- SIMBAD 83 Leo A entry, 83 Leo B entry, 83 Leo C entry
- The Extrasolar Planets Encyclopaedia entry
- Extrasolar Visions — artwork and speculations
[edit] References
- ^ Marcy et al. (2005). "Five New Extrasolar Planets". The Astrophysical Journal 619 (1): 570 – 584. doi:.
- ^ The Planet Around HD 99492. California & Carnegie Planet Search. Retrieved on 2006-05-09.
- ^ Raghavan et al. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems" (abstract). The Astrophysical Journal 646 (1): 523 – 542. doi:. (web Preprint)
- ^ Butler et al. (2006). "Catalog of Nearby Exoplanets" (abstract). The Astrophysical Journal 646 (1): 505 – 522. doi:. (web Preprint)
