:INFO
Ice giant around TOI-791
It is 1.15 times Jupiter's radius, closest in size to Jupiter, and 18.6 times Earth's mass, at 0.05 g/cm3, less dense than Earth. A year there lasts 232.02 days, on an orbit 2.2 times Mercury's distance from the Sun. Its equilibrium temperature is 363 K, hotter than any desert. The host star TOI-791 runs at 6294 K with 1.28 times the Sun's mass.

:STATS
[icon:TARGET] Radius | 12.95 Earth radii
[icon:CHART] Mass | 18.6 Earth masses
[icon:FIRE] Equilibrium temperature | 363 K (measured)
[icon:CLOCK] One year | 232.02 days
[icon:BOLT] Orbit radius | 0.8630 AU
[icon:STAR] Host star | TOI-791 at 6294 K
[icon:USERS] Distance | 1113 light-years
[icon:TRENDING_DOWN] Starlight blocked | 0.647% at each transit

:COUNTER
0.05 g/cm3: less dense than cork

:CHECKLIST
The habitability checklist, honestly scored
[ ] Orbits inside the computed habitable zone. No.
[ ] Dense enough to be rock rather than gas, at 0.05 g/cm3. No.
[ ] A measured mass, not just a radius. Yes.
[ ] A measured temperature rather than one derived from the star. Yes.
[ ] Any detection of an atmosphere. Not recorded in the archive.

:PATH
What you get from the shadow
The depth of the dip is the ratio of the two discs, so the radius follows.

:NOTE
Found by Transiting Exoplanet Survey Satellite (TESS) in 2026. TESS scans most of the sky in 27-day stretches, so it favours bright nearby stars and short orbits over the faint distant ones Kepler specialised in.

:NOTE
A transit gives the radius and a separate measurement gives the mass. Having both is what makes a density, and a density is the only clue to composition at this range.

:NOTE
TOI-791 has 2 known planets. Planets in company tug on each other, and those tugs are measurable, which is how masses get pinned down without a wobble.

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/TOI-791%20c
NASA Exoplanet Archive: source data, including the values not used here