HD 80606b Spin-orbit misalignement

View previous topic View next topic Go down

HD 80606b Spin-orbit misalignement

Post by Sirius_Alpha on 28th June 2009, 8:24 pm

Spin-orbit misalignement for the transiting planet HD 80606b
http://arxiv.org/abs/0906.4904

Abstract wrote:A global Markov Chain Monte Carlo analysis of published eclipse photometry and radial velocities is presented for the transiting planet HD 80606b. Despite the lack of a complete transit light curve, the size of the planet is measured with a good level of precision (R_p = 1.04 +0.05-0.09 R_Jup), while the orbital parameters are refined. This global analysis reveals that the orbital axis of the planet is significatively inclined relative to the spin axis of the host star (Beta = -59 +18-28 deg), providing a compelling evidence that HD 80606b owes its peculiar orbit to the Kozai migration mechanism.

_________________
Caps Lock: Cruise control for 'Cool'!
avatar
Sirius_Alpha
Admin
Admin

Number of posts : 3528
Location : Earth
Registration date : 2008-04-06

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

Back to top Go down

Re: HD 80606b Spin-orbit misalignement

Post by NuclearVacuum on 29th June 2009, 1:01 am

Wow!!! sunny

_________________
I'm a renegade, fear me!
avatar
NuclearVacuum
Terrestrial Planet
Terrestrial Planet

Number of posts : 155
Age : 27
Location : Delta Trianguli
Registration date : 2008-07-05

View user profile http://nuclearvacuum.wikia.com

Back to top Go down

Re: HD 80606b Spin-orbit misalignement

Post by Lazarus on 29th June 2009, 2:56 am

Let's see whether this figure gets significantly revised with data from the next transit(s).
avatar
Lazarus
dG star
dG star

Number of posts : 2894
Registration date : 2008-06-12

View user profile

Back to top Go down

Re: HD 80606b Spin-orbit misalignement

Post by Sirius_Alpha on 30th June 2009, 8:07 pm

It's amazing how much HD 80606 b has been examined. At every opportunity so far, several independent teams report essentially the same thing, providing strong independent confirmation for the parameters of this planet. Speaking of which:


Spin-Orbit Mislaignment in the HD 80606 planetary system
http://arxiv.org/abs/0906.5605

Abstract wrote:We recently reported the photometric and spectroscopic detection of the primary transit of the 111-day-period, eccentric extra-solar planet HD80606 b, at Observatoire de Haute-Provence, France (Moutou et al. 2009). The whole egress of the primary transit and a section of its central part were observed, allowing the measurement of the planetary radius, and evidence for a spin-orbit misalignment through the observation of the Rossiter-McLaughlin anomaly. The ingress having not been observed for this long-duration transit, uncertainties remained in the parameters of the system. We present here a refined, combined analysis of our photometric and spectroscopic data, together with further published radial velocities, ground-based photometry, and Spitzer photometry around the secondary eclipse, as well as new photometric measurements of HD 80606 acquired at Mount Hopkins, Arizona, just before the beginning of the primary transit. Although the transit is not detected in those new data, they provide an upper limit for the transit duration, which narrows down the possible behaviour of the Rossiter-McLaughlin anomaly in the unobserved part of the transit. We analyse the whole data with a Bayesian approach using a Markov-chain Monte Carlo integration on all available information. We find R_p = 0.98 +- 0.03 R_Jup for the planetary radius, and a total primary transit duration of 11.9 +- 1.3 hours from first to fourth contact. Our analysis reinforces the hypothesis of spin-orbit misalignment in this system (alignment excluded at >95 % level), with a positive projected angle between the planetary orbital axis and the stellar rotation (median solution lambda ~ 50 degrees). As HD80606 is a component of a binary system, the peculiar orbit of its planet could result from a Kozai mechanism.

_________________
Caps Lock: Cruise control for 'Cool'!
avatar
Sirius_Alpha
Admin
Admin

Number of posts : 3528
Location : Earth
Registration date : 2008-04-06

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

Back to top Go down

Re: HD 80606b Spin-orbit misalignement

Post by Sponsored content


Sponsored content


Back to top Go down

View previous topic View next topic Back to top


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