Starship Asterisk*

[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. ...

• 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)

Wikipedia wrote:The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stated by Émile Clapeyron in 1834 as a combination of the empirical Boyle's law, Charles's law and Avogadro's law.[1] The ideal gas law is often written as

PV=nRT, where:
P is the pressure of the gas,
V is the volume of the gas,
n is the amount of substance of gas (in moles),
R is the ideal, or universal, gas constant, equal to the product of the Boltzmann constant and the Avogadro constant,
T is the absolute temperature of the gas.

It can also be derived from the microscopic kinetic theory, as was achieved (apparently independently) by August Krönig in 1856[2] and Rudolf Clausius in 1857.[3]