TOI-1518 b
TOI-1518 b is a hot Jupiter orbiting TOI-1518 in the constellation Cepheus. It lies about 737 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is TOI-1518 b?
TOI-1518 b has a radius of 21.05 times that of Earth, or 1.88 times the radius of Jupiter. Its mass is 582 times that of Earth, giving it a density of 0.34 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-1518 b in the Habitable Zone?
The position of TOI-1518 b relative to the habitable zone of TOI-1518 cannot be precisely determined from the available orbital data.
Temperature on TOI-1518 b
The equilibrium temperature of TOI-1518 b is about 2,546 K (2,273 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 7,010 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-1518 b — one full orbit around TOI-1518 — lasts just 45.7 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.037 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1518 b Discovered?
TOI-1518 b was discovered in 2021 using the transit method, with observations from Multiple Observatories.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is TOI-1518 b?
TOI-1518 b is 736.7 light-years (225.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1290. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 12,965,920 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. TOI-1518 b scores 0.04, ranking #5,311 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1518
TOI-1518
- Surface temperature
- 7,299 K (Sun: 5,772 K)
- Mass
- 1.88 M☉
- Radius
- 1.94 R☉
- Luminosity
- 9.6401 L☉
Planetary System
TOI-1518 b is the only planet known to orbit TOI-1518 so far.
TOI-1518 b — Complete Data
| Radius | 21.050 Earth radii (1.878 Jupiter radii) |
|---|---|
| Mass | 581.63 Earth masses (1.830 Jupiter masses) |
| Density | 0.34 g/cm³ (Earth: 5.51) |
| Orbital period | 1.90 days |
| Orbital distance | 0.037 AU |
| Equilibrium temperature | 2,546 K (2,273 °C) |
| Stellar irradiation | 7,010.00× Earth |
| Earth Similarity Index | 0.04 |
| Distance from Earth | 736.7 light-years (225.9 parsecs) |
| Constellation | Cepheus |
| Discovery method | Transit |
| Discovery facility | Multiple Observatories |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2026-02-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1518 b
Is TOI-1518 b habitable?
TOI-1518 b is not known to orbit within the habitable zone of TOI-1518, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is TOI-1518 b?
TOI-1518 b is about 737 light-years from Earth in the constellation Cepheus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 12,965,920 years to get there.
How big is TOI-1518 b compared to Earth?
TOI-1518 b has 21.05 times the radius of Earth and about 582 times its mass.
How long is a year on TOI-1518 b?
One orbit around TOI-1518 takes 1.9 Earth days — short enough that 192 of its years would fit into one Earth year.
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