Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: TrES-4b spin-orbit alignment and hints of TrES-4 c? 12th March 2010, 8:11 am | |
| Spin-Orbit Alignment of the TrES-4 Transiting Planetary System and Possible Additional Radial Velocity Variation http://arxiv.org/abs/1003.2268 - Abstract wrote:
- We report new radial velocities of the TrES-4 transiting planetary system, including observations of a full transit, with the High Dispersion Spectrograph of the Subaru 8.2m telescope. Modeling of the Rossiter-McLaughlin effect indicates that TrES-4b has closely aligned orbital and stellar spin axes, with $\lambda = 6.3^{\circ} \pm 4.7^{\circ}$. The close spin-orbit alignment angle of TrES-4b seems to argue against a migration history involving planet-planet scattering or Kozai cycles, although there are two nearby faint stars that could be binary companion candidates. Comparison of our out-of-transit data from 4 different runs suggest that the star exhibits radial velocity variability of $\sim$20 ms^-1 in excess of a single Keplerian orbit. Although the cause of the excess radial velocity variability is unknown, we discuss various possibilities including systematic measurement errors, starspots or other intrinsic motions, and additional companions besides the transiting planet.
_________________ Caps Lock: Cruise control for 'Cool'!
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exoplanet Planetesimal
Number of posts : 124 Location : here Registration date : 2008-06-16
| Subject: Re: TrES-4b spin-orbit alignment and hints of TrES-4 c? 12th March 2010, 9:27 am | |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: TrES-4b spin-orbit alignment and hints of TrES-4 c? 12th March 2010, 9:39 am | |
| That's not a bad idea at all. _________________ Caps Lock: Cruise control for 'Cool'!
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: TrES-4b spin-orbit alignment and hints of TrES-4 c? 27th January 2015, 11:23 am | |
| http://arxiv.org/abs/1501.06403The GAPS Programme with HARPS-N@TNG VI: The Curious Case of TrES-4b We revisit the TrES-4 system parameters based on high-precision HARPS-N radial-velocity measurements and new photometric light curves. A combined spectroscopic and photometric analysis allows us to determine a spectroscopic orbit with an amplitude K=51±3 m s−1. The derived mass of TrES-4b is found to be Mp=0.49±0.04MJup, significantly lower than previously reported. Combined with the large radius (Rp=1.84+0.08−0.09RJup) inferred from our analysis, TrES-4b becomes the second-lowest density transiting hot Jupiter known. We discuss several scenarios to explain the puzzling discrepancy in the mass of TrES-4b in the context of the exotic class of highly inflated transiting giant planets | |
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| Subject: Re: TrES-4b spin-orbit alignment and hints of TrES-4 c? | |
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