TOI-5398 b
Gas GiantUninhabitable427 light years awayFound 2022
TOI-5398 b, from the NASA Exoplanet Archive (found 2022). Measured: 58.7 Earth masses, 0.098 AU, a 6000 K F-type star. Composition inferred from a mass of 58.7 Earths, which is giant territory whatever its 0.05x density suggests, with a day locked to its 10.6-day year, as anything orbiting this close would be.
TOI-5398
- Type
- F-type (White)
- Spectral type
- G V
- Temperature
- 6,000 K
- Radius
- 1.05 ☉
- Mass
- 1.15 ☉
- Known planets
- 2, including this one
- Luminosity
- 1.31 ☉
Published by the NASA Exoplanet Archive. This world’s temperature and habitability score are computed from this star’s measured luminosity, not from a stand-in for its class.
Gas Giant
Magnetic FieldExtreme Activity
Why is this a Gas Giant?Your planet has 86.0% hydrogen and helium, combined with a mass of 58.7x Earth, which exceeds the gas giant threshold.
Gas giants form when massive cores capture enormous atmospheres of light gases. They typically form beyond the 'frost line' where volatiles can condense.
Classification Criteria:
✓ Hydrogen + Helium: 86.0% (>60% required)✓ Mass: 58.7x Earth (>10x required)
Habitability ScoreUninhabitable
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for life
atmosphere18
Hydrogen-rich atmosphere typical of gas giants (partially stripped by slow rotation)
water15
No solid surface — any water is locked in a supercritical mantle and hot ice, not oceans
magnetic Field100
Magnetic field provides radiation protection
geology40
Extreme volcanic activity may be hazardous
Organic Chemistry80
Core organic elements (CHNO) present
rotation30
Very slow rotation - extreme temperature swings between eternal day and night sides
Physical Properties
Mass
58.70x Earth (3.51e+26 kg)Radius
3.89x Earth (24,760 km)Surface Gravity
3.89x Earth (38.1 m/s²)Surface Temperature
952 K (679 °C / 1,255 °F)Rotation Period
254.4 hours/day (slower than Earth)Orbital Environment
Star Type
F-type (White)Distance from Star
0.10 AU (14.7 million km)Orbital Period
10 daysTime Dilation
Clocks run 6.2 seconds per year slower than deep space — about 8 minutes over a lifetimeAtmosphere
Hydrogen and helium dominated with trace methane and ammonia
Elemental Composition
H - Hydrogen
53.8%
He - Helium
32.3%
O - Oxygen
5.4%



