:INFO
Gas giant around TOI-1408
It is 2.23 times Jupiter's radius, closest in size to Jupiter, and 593.0 times Earth's mass, at 0.18 g/cm3, less dense than Earth. A year there lasts 4.43 days, on an orbit 7 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 1388 K (derived from the star rather than measured), hot enough to melt lead. The host star TOI-1408 runs at 6117 K with 1.31 times the Sun's mass.

:STATS
[icon:TARGET] Radius | 25.00 Earth radii
[icon:CHART] Mass | 593.0 Earth masses
[icon:FIRE] Equilibrium temperature | 1388 K (derived)
[icon:CLOCK] One year | 4.43 days
[icon:BOLT] Orbit radius | 0.0578 AU
[icon:STAR] Host star | TOI-1408 at 6117 K
[icon:USERS] Distance | 455 light-years
[icon:TRENDING_DOWN] Starlight blocked | 2.239% at each transit

:COUNTER
2.2x Jupiter: among the largest planets measured

:TIMELINE
🔭🪐📅
2023-01-01 | TOI-1408 b
2024-01-01 | TOI-1408 c

:CHECKLIST
The state of the record for this planet
[ ] A measured radius. Yes.
[ ] A weight, not just a width. Yes.
[ ] A density, so rock and gas can be told apart. Yes.
[ ] A semi-major axis. Yes.
[ ] A measured temperature rather than a derived one. No.
[ ] The shape of the orbit. Yes.

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

:NOTE
The archive lists no measured equilibrium temperature for this planet. The 1388 K quoted here is derived from the star's output and the orbital distance, assuming a third of the light is reflected. It is an estimate from two numbers, not an observation.

:NOTE.half
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.half
TOI-1408 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.

:NOTE
Found by Transiting Exoplanet Survey Satellite (TESS) in 2023. 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.

:THREAD

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/TOI-1408%20b
NASA Exoplanet Archive: source data, including the values not used here