Institute for Astronomy | University of Hawaii | 2017 Nov 27
[c][attachment=0]K2-132b-1600x700[1].jpg[/attachment][/c][hr][/hr]Since astronomers first measured the size of an extrasolar planet seventeen years ago, they have struggled to answer the question: how did the largest planets get to be so large? Thanks to the recent discovery of twin planets by a University of Hawaii Institute for Astronomy team lead by graduate student Samuel Grunblatt, we are getting closer to an answer.
Gas giant planets are primarily made out of hydrogen and helium, and are at least 4 times the diameter of Earth. Gas giant planets that orbit scorchingly close to their host stars are known as "hot Jupiters". These planets have masses similar to Jupiter and Saturn, but tend to be much larger - some are puffed up to sizes even larger than the smallest stars.
The unusually large sizes of these planets are likely related to heat flowing in and out of the their atmospheres, and several theories have been developed to explain this process. "However, since we don't have millions of years to see how a particular planetary system evolves, planet inflation theories have been difficult to prove or disprove," said Grunblatt. ...
Seeing Double with K2: Testing Re-inflation with Two Remarkably
Similar Planets around Red Giant Branch Stars - Samuel K. Grunblatt et al
- Astronomical Journal 154(6):254 (Dec 2017) DOI: 10.3847/1538-3881/aa932d
arXiv.org > astro-ph > arXiv:1706.05865 > 19 Jun 2017 (v1), 12 Oct 2017 (v2)