WASP-123 b
Gas GiantUninhabitable645 light years awayFound 2016
WASP-123 b, from the NASA Exoplanet Archive (found 2016). Measured: 286 Earth masses, 0.0426 AU, a 5740 K G-type star. Composition inferred from a mass of 286 Earths, which is giant territory whatever its 0.08x density suggests, with a day locked to its 3.0-day year, as anything orbiting this close would be.
WASP-123
- Type
- G-type (Yellow (Sun-like))
- Spectral type
- G5
- Temperature
- 5,740 K
- Radius
- 1.28 ☉
- Mass
- 1.17 ☉
- Known planets
- 1 (this one)
- Luminosity
- 1.45 ☉
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 286.0x 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: 286.0x Earth (>10x required)
Habitability ScoreUninhabitable
Contributing Factors
temperature0
Inferno world - temperatures exceed all possibility of life
atmosphere30
Hydrogen-rich atmosphere typical of gas giants
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
rotation65
Slow rotation - significant day/night temperature variations, but life can adapt
Physical Properties
Mass
286.00x Earth (1.71e+27 kg)Radius
6.59x Earth (41,976 km)Surface Gravity
6.59x Earth (64.6 m/s²)Surface Temperature
1,481 K (1,208 °C / 2,206 °F)Rotation Period
71.5 hours/day (slower than Earth)Orbital Environment
Star Type
G-type (Yellow (Sun-like))Distance from Star
0.04 AU (6.37 million km)Orbital Period
3 daysTime Dilation
Clocks run 11.0 seconds per year slower than deep space — about 15 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%



