TOI-1898 b: 129.0 Earth Masses
Gas giant around TOI-1898
It is 0.84 times Jupiter's radius, closest in size to Saturn, and 129.0 times Earth's mass, at 0.85 g/cm3, less dense than Earth. A year there lasts 45.52 days, on an orbit 1 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 675 K, hotter than any desert. The host star TOI-1898 runs at 6241 K with 1.25 times the Sun's mass.
Radius
9.40 Earth radii
Mass
129.0 Earth masses
Equilibrium temperature
675 K (measured)
One year
45.52 days
Orbit radius
0.2690 AU
Host star
TOI-1898 at 6241 K
Distance
260 light-years
Starlight blocked
0.285% at each transit
What the transit gives
How deep the star dims fixes the planet's size relative to it.
Found by Transiting Exoplanet Survey Satellite (TESS) in 2024. 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.
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.
Its orbit is noticeably elliptical, eccentricity 0.48, so the starlight it receives changes substantially over one year.
