Comments on: hot and bothered http://oklo.org/2007/01/21/hot-and-bothered/ characterizing planetary systems Wed, 18 Apr 2012 18:53:22 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: markk http://oklo.org/2007/01/21/hot-and-bothered/comment-page-1/#comment-979 markk Tue, 23 Jan 2007 18:38:18 +0000 http://oklo.org/?p=184#comment-979 Very interesting post. Has anyone modelled what potential magnetospheres might look like for a hot Jupiter in one of the Cassini states? I imagine there could be some rather exotic solutions. Mark Very interesting post. Has anyone modelled what potential magnetospheres might look like for a hot Jupiter in one of the Cassini states? I imagine there could be some rather exotic solutions.

Mark

]]> By: andy http://oklo.org/2007/01/21/hot-and-bothered/comment-page-1/#comment-978 andy Tue, 23 Jan 2007 13:51:09 +0000 http://oklo.org/?p=184#comment-978 That's a rather unexpected result, thanks for posting it! Regarding inflated radii, <a href="http://fr.arxiv.org/abs/astro-ph/0612703" rel="nofollow">this</a> suggests that metallicity of the atmosphere might be to blame. That’s a rather unexpected result, thanks for posting it! Regarding inflated radii, this suggests that metallicity of the atmosphere might be to blame.

]]> By: greg http://oklo.org/2007/01/21/hot-and-bothered/comment-page-1/#comment-975 greg Tue, 23 Jan 2007 06:35:03 +0000 http://oklo.org/?p=184#comment-975 Hi Darin, That's an excellent point. With the models that we have in hand, it's a relatively straightforward computation to get the high-resolution lightcurves for the ingress and the egress when the planet goes behind the star. I'm optimistic that these will show considerable differences between the Cassini state 1 and Cassini state 2 cases. The one fly in the ointment is that if the planet is in Cassini state 2, we don't know the orientation of the planet's spin angular momentum vector (aside from the fact that it lies in the planetary orbital plane). For a given hydrodynamic model, there'll thus be a one-parameter sequence of possible ingress and egress lightcurves. Viewed from Earth, the surface flow patterns in our Cassini State 1 and Cassini State 2 animations are qualitatively very different. I was thus surprised to see how sinusoidal the final full-phase light curves actually came out. It'll be very cool if the ingress and egress curves show more of a difference. Regarding the light-curve for 209458b discussed at the most recent AAS meeting, I think that you're referring to the Cowan-Agol-Charbonneau poster. It looks like the signal-to-noise that they were able to achieve at 8-microns was not high enough to put interesting limits on the HD 209458b temperature distribution. For several other planets, though, they got better signal-to-noise, and found that there was little temperature variation between the day and the night sides. This was in stark contrast to the 24-micron result for Upsilon Andromedae, which suggested a very large day-night side difference in temperature. Greg Hi Darin,

That’s an excellent point. With the models that we have in hand, it’s a relatively straightforward computation to get the high-resolution lightcurves for the ingress and the egress when the planet goes behind the star. I’m optimistic that these will show considerable differences between the Cassini state 1 and Cassini state 2 cases.

The one fly in the ointment is that if the planet is in Cassini state 2, we don’t know the orientation of the planet’s spin angular momentum vector (aside from the fact that it lies in the planetary orbital plane). For a given hydrodynamic model, there’ll thus be a one-parameter sequence of possible ingress and egress lightcurves.

Viewed from Earth, the surface flow patterns in our Cassini State 1 and Cassini State 2 animations are qualitatively very different. I was thus surprised to see how sinusoidal the final full-phase light curves actually came out. It’ll be very cool if the ingress and egress curves show more of a difference.

Regarding the light-curve for 209458b discussed at the most recent AAS meeting, I think that you’re referring to the Cowan-Agol-Charbonneau poster. It looks like the signal-to-noise that they were able to achieve at 8-microns was not high enough to put interesting limits on the HD 209458b temperature distribution. For several other planets, though, they got better signal-to-noise, and found that there was little temperature variation between the day and the night sides. This was in stark contrast to the 24-micron result for Upsilon Andromedae, which suggested a very large day-night side difference in temperature.

Greg

]]> By: darin http://oklo.org/2007/01/21/hot-and-bothered/comment-page-1/#comment-973 darin Tue, 23 Jan 2007 05:02:30 +0000 http://oklo.org/?p=184#comment-973 Greg- Theoretically, through careful observations of the ingress and egress, people (e.g. Williams et al. 2006) have talked about getting some longitudinal resolution of images of the surfaces of transiting planets. I wonder if you could tell the difference between planets in the two Cassini states using this method. Since they look so different it seems like this method of "spatially resolving" the planet could be helpful. I believe a light-curve for 209458b has been recently obtained (and discussed at the most recent AAS meeting). Darin Greg-

Theoretically, through careful observations of the ingress and egress, people (e.g. Williams et al. 2006) have talked about getting some longitudinal resolution of images of the surfaces of transiting planets. I wonder if you could tell the difference between planets in the two Cassini states using this method. Since they look so different it seems like this method of “spatially resolving” the planet could be helpful.

I believe a light-curve for 209458b has been recently obtained (and discussed at the most recent AAS meeting).

Darin

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