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The latest anomalies

June 8th, 2012

Photographed at UCSC Art Dept. Spring 2012 Open Studios

The announcement of new transiting hot-Jupiter type planets, such as WASP 79b or HAT-P-38b, by the ground-based surveys no longer generates press releases, but the march of discovery does give us an ever-clearer view of the planetary census.

Yesterday, Matteo Crismani turned in his UCSC Senior Thesis. In addition to the results that we published in our 2011 paper (described in this post and this post) he also took an updated look at the relationship between the radius anomaly (the fractional discrepancy between the theoretically predicted radius and the actual observed radius) and the insolation-derived effective temperature of the planet. With the large aggregate of hot Jupiter-class planets that now have good measurements for both planetary mass and planetary radius, the dependence of the radius anomaly on the planetary temperature has grown clearer.

The best fit power-law now has the radius anomaly scaling as T^2.9, with an uncertainty on the exponent of ~0.3. This is quite close to the T^2.6 relation that stems from the back-of-the-envelope arguments that invoke the Batygin-Stevenson Ohmic heating mechanism. In effect, these hot Jupiters are like Ball Park Franks…

  1. greg
    June 8th, 2012 at 14:12 | #1
  2. a_scientist
    June 24th, 2012 at 20:23 | #2

    I have a hard time understanding your fit. All I can see from the data points is that below ~2000K there are barely any inflated planets while roughly half of the planets beyond ~2000K are inflated. I bet if you fit the data beyond 2000K, it is consistently with having no trend at all.

  3. hid3gold
    July 18th, 2012 at 19:31 | #3

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