|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
A ~ 7.5 Earth-Mass Planet Orbiting the Nearby Star, GJ 876
Haven't seen Jason post anything about this .... I think this must be
the record for the lowest mass extrasolar planet orbiting a main-sequence star. They are starting to push into terrestrial-mass planet territory. Title: A ~ 7.5 Earth-Mass Planet Orbiting the Nearby Star, GJ 876 Authors: E. J. Rivera, J. J. Lissauer, R. P. Butler, G. W. Marcy, S. S. Vogt, D. A. Fischer, T. M. Brown, G. Laughlin, G. W. Henry Journal-ref: Astrophys.J. 634 (2005) 625 High precision, high cadence radial velocity monitoring over the past 8 years at the W. M. Keck Observatory reveals evidence for a third planet orbiting the nearby (4.69 pc) dM4 star GJ 876. The residuals of three-body Newtonian fits, which include GJ 876 and Jupiter mass companions b and c, show significant power at a periodicity of 1.9379 days. Self-consistently fitting the radial velocity data with a model that includes an additional body with this period significantly improves the quality of the fit. These four-body (three-planet) Newtonian fits find that the minimum mass of companion ``d'' is m sin i = 5.89 +- 0.54 Earth masses and that its orbital period is 1.93776 (+- 7x10^-5) days. Assuming coplanar orbits, an inclination of the GJ 876 planetary system to the plane of the sky of ~ 50 degrees gives the best fit. This inclination yields a mass for companion d of m = 7.53 +- 0.70 Earth masses, making it by far the lowest mass companion yet found around a main sequence star other than our Sun. Precise photometric observations at Fairborn Observatory confirm low-level brightness variability in GJ 876 and provide the first explicit determination of the star's 96.7-day rotation period. Even higher precision short-term photometric measurements obtained at Las Campanas imply that planet d does not transit GJ 876. URL: http://xxx.lanl.gov/abs/astro-ph?papernum=10508 -- Lt. Lazio, HTML police | e-mail: No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Space Calendar - November 23, 2005 | [email protected] | History | 2 | November 25th 05 02:36 AM |
Space Calendar - July 28, 2004 | Ron | Astronomy Misc | 0 | July 28th 04 05:18 PM |
Space Calendar - June 25, 2004 | Ron | Astronomy Misc | 0 | June 25th 04 04:37 PM |
Space Calendar - June 25, 2004 | Ron | Misc | 0 | June 25th 04 04:37 PM |
Space Calendar - May 28, 2004 | Ron | Astronomy Misc | 0 | May 28th 04 04:03 PM |