Evidence for additional planet at XO-2?

Go down

Evidence for additional planet at XO-2?

Post by Sirius_Alpha on 27th October 2011, 8:26 pm

XO-2b: a Prograde Planet with a Negligible Eccentricity, and an Additional Radial Velocity Variation

We present precise radial velocities of XO-2 taken with the Subaru HDS, covering two transits of XO-2b with an interval of nearly two years. The data suggest that the orbital eccentricity of XO-2b is consistent with zero within 2$\sigma$ ($e=0.045\pm0.024$) and the orbit of XO-2b is prograde (the sky-projected spin-orbit alignment angle $\lambda=10^{\circ}\pm72^{\circ}$). The poor constraint of $\lambda$ is due to a small impact parameter (the orbital inclination of XO-2b is almost 90$^{\circ}$). The data also provide an improved estimate of the mass of XO-2b as $0.62\pm0.02$ $M_{\rm Jup}$. We also find a long-term radial velocity variation in this system. Further radial velocity measurements are necessary to specify the cause of this additional variation.

Caps Lock: Cruise control for 'Cool'!

Number of posts : 3571
Location : Earth
Registration date : 2008-04-06

View user profile http://solar-flux.forumandco.com/

Back to top Go down

Back to top

Permissions in this forum:
You cannot reply to topics in this forum