If Jupiter was orbiting at 1AU, replacing Earth, but everything else in the solar system remained as it is currently, how much would the increased heat from the sun increase Jupiter's radius?

In other words, how much would Jupiter fluff up if it was closer to the sun?

Would that be close enough to classify it as a warm jupiter, or hot jupiter? or would it still just be a standard jovian planet?


Radius inflation seems to mainly occur in planets with irradiation in the range 105–106 W/m2, see Sestovic et al. (2018). In contrast, at 1 AU from the Sun, the irradiation is 1361 W/m2, which is well below the threshold at which the inflated gas giant radii are observed. It seems unlikely to me that there would be a significant increase in the radius of Jupiter if it were moved to a 1 AU orbit.

As regards the hot/warm Jupiter classification, the term "hot Jupiter" seems to mainly be used to describe the population of giant planets with orbital periods below about 10 days or so. Your Jupiter at 1 AU would not fall into this category.

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    $\begingroup$ Minor point, but the orbital radius has to be taken into account with the radiation of the star. A large enough star, and you can have a hot Jupiter at 1 AU. 2 solar masses and 1 AU, the planet would be in the range of 10^5 W/m^2. $\endgroup$
    – userLTK
    Dec 25 '18 at 0:02
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    $\begingroup$ True, but the question did specify that the Sun was being kept the same. The issue of whether or not a planet at 1 AU around a sufficiently luminous star counts as a hot Jupiter or not is a matter for another question. $\endgroup$
    – user24157
    Dec 25 '18 at 10:33

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