TOI-2134 c: Habitable Zone, 96-Day Year
Gas giant around TOI-2134
It is 7.35 times Earth's radius, closest in size to Saturn, and 58.3 times Earth's mass, at 0.81 g/cm3, less dense than Earth. A year there lasts 95.85 days, on an orbit 1 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 302 K, in the range where liquid water is possible. The host star TOI-2134 runs at 4580 K with 0.74 times the Sun's mass.
What this planet has and has not got
Sits inside the computed habitable zone of its star. Yes.
Dense enough to be rock rather than gas, at 0.81 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.
Radius
7.35 Earth radii
Mass
58.3 Earth masses
Equilibrium temperature
302 K (measured)
One year
95.85 days
Orbit radius
0.3715 AU
Host star
TOI-2134 at 4580 K
Distance
74 light-years
Starlight blocked
0.901% at each transit
What you get from the shadow
How deep the star dims fixes the planet's size relative to it.
Size from the shadow, mass from elsewhere. Most transiting planets never get the second half, and without it composition stays a guess.
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.
TOI-2134 has 2 known planets. Systems like this are the ones where architecture can be studied instead of guessed at.
Its orbit is noticeably elliptical, eccentricity 0.31, so the starlight it receives changes substantially over one year.
TOI-2134 c sits in the habitable zone on the arithmetic alone. That says where \
it orbits, not what it is like. What would you want measured next before calling it promising?
