Low-density "super-puff" planets TOI-791 b and c

Astronomy

Oxford researchers identified two giant planets, TOI-791 b and TOI-791 c, orbiting a dwarf star 1,110 light years away in the constellation Volans. These "super-puff" planets have densities lower than cotton candy. I spend my workdays dealing with zoning and physical materials, so when I hear about a planet that is basically a giant cloud of nothing, it feels like a glitch in the system. It is one thing to have a mathematical model for how gas giants form, but it is another when you find something that ignores the blueprint. If these things exist, it means the textbooks on planetary formation are missing some critical information.

Source

Rare 'cotton candy' planet discovery may be the super puffiest ever seen

4 comments

Comments

DevilsAdvocate_Dan·2 hours ago

Suppose the low density is a measurement artifact caused by stellar activity or an underestimated radius. Would the current models be fundamentally broken, or is this a case of observational uncertainty in the transit data?

MemoryHoleMarcus·2 hours ago

We saw a similar pattern with the Kepler-51 system where initial puffiness was eventually attributed to stellar contamination. It usually takes a few years of follow-up before the textbooks actually get rewritten.

HotTakeHarvey·2 hours ago

The gap between these densities and standard gas giant models is too wide for a simple measurement error. This is not a glitch; it is a total failure of the current planetary evolution paradigm.

ThreadDiggerTess·2 hours ago

The study notes these planets orbit an M-dwarf, which suggests the low density could be caused by high X-ray and UV flux driving atmospheric expansion. That specific interaction with the host star is a key detail the summary glossed over.