Epoch J2000.0 Equinox J2000.0
|Right ascension||08h 40m 59.24s|
|Declination||−23° 27′ 23.3″|
|Apparent magnitude (V)||11.98
|Variable type||none reported|
|Radial velocity (Rv)||87.8 km/s|
|Proper motion (μ)||RA: -438 mas/yr
Dec.: 794 mas/yr
|Parallax (π)||65.3 ± 0.5 mas|
|Distance||49.9 ± 0.4 ly
(15.3 ± 0.1 pc)
|Mass||0.43  M☉|
|Metallicity [Fe/H]||+0.3 dex|
Gliese 317 is a red dwarf approximately 50 light-years away in the constellation of Pyxis. As of 2011[update], two extrasolar planets have been confirmed to be orbiting the star. Photometric calibrations and infrared spectroscopic measurements indicate that the star is enriched in heavy elements compared to the Sun.
In 2007, a jovian planet (designated Gliese 317 b) was announced to orbit the star. The planet orbits about 95% the distance between Earth to the Sun. Despite of this, it takes about 1.9 years, due to the lower mass of the central M dwarf. Astrometric measurements on Gliese 317 provided a significant update to the distance, putting the star at 15.3 pc, which is 65% further out than previously assumed. Using mass-luminosity calibrations, the new distance implies the star is significantly more massive and so are the planet candidates. The same astrometric measurements allowed to constrain the orbital inclination and put an upper limit to the mass of Gliese 317 b (98% confidence level) of 2.5 M_jup.
The second planet in the system was also confirmed with the additional new RV measurements, but the period and orbital parameters of Gliese 317 c are still very uncertain (P>2000 days). A stability analysis on this putative system suggest that the pair of gas giant planets are in a 4:1 mean motion resonance.
(in order from star)
|b||>1.81 ± 0.05 MJ||1.148||692.0 ± 2||0.11 ± 0.05||—||—|
|c (unconfirmed)||≥1.6 MJ||≥5.5||≥7100||unknown||—||—|
- Anglada-Escude, Guillem et al. (2012), "Astrometry and radial velocities of the planet host M dwarf Gliese 317: new trigonometric distance, metallicity and upper limit to the mass of Gliese 317 b", The Astrophysical Journal 764 (1): 37A, arXiv:1111.2623, Bibcode:2012ApJ...746...37A, doi:10.1088/0004-637X/746/1/37
- Terrien, Ryan C. et al., An H-band Spectroscopic Metallicity Calibration for M Dwarfs, arXiv:1202.1800, Bibcode:2012ApJ...747L..38T, doi:10.1088/2041-8205/747/2/L38
- Johnson, J. A. et al. (2007), "A New Planet Around an M Dwarf: Revealing a Correlation between Exoplanets and Stellar Mass", The Astrophysical Journal 670 (1): 833–840, arXiv:0707.2409, Bibcode:2007ApJ...670..833J, doi:10.1086/521720
- Rory Barnes; Richard Greenberg (2008). "Extrasolar Planet Interactions". arXiv:0801.3226v1 [astro-ph].
- "Notes for star GJ 317". The Extrasolar Planet Encyclopedia. Retrieved 2008-08-09.
- Extrasolar Planet Interactions by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona
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