GJ 367 b: A Year In 7.7 Hours
Terrestrial around GJ 367
It is 0.74 times Earth's radius, closest in size to Venus, and 0.5 times Earth's mass, at 6.90 g/cm3, denser than Earth. A year there lasts 7.7 hours. Its equilibrium temperature is 1329 K, hot enough to melt lead. The host star GJ 367 runs at 3535 K with 0.45 times the Sun's mass.
7.7hours: one full year, start to finish
Radius
0.74 Earth radii
Mass
0.5 Earth masses
Equilibrium temperature
1329 K (measured)
One year
7.7 hours
Host star
GJ 367 at 3535 K
Distance
31 light-years
Starlight blocked
0.022% at each transit
Known and unknown, as the archive has it
A size. Yes.
A weight, not just a width. Yes.
A density, the one clue to composition. Yes.
A semi-major axis. No.
A temperature someone observed rather than calculated. Yes.
An eccentricity, so the orbit shape is known. Yes.
What the transit gives
The depth of the dip is the ratio of the two discs, so the radius follows.
The size came from a crossing, the mass did not. That pairing is uncommon and it is what lets anyone say whether this is rock or gas.
GJ 367 has 3 known planets. Systems like this are the ones where architecture can be studied instead of guessed at.
Found by Transiting Exoplanet Survey Satellite (TESS) in 2021. 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.
