TOI-1117 d
TOI-1117 d is a Neptune-like planet orbiting the G5 V star TOI-1117 in the constellation Pavo. It lies about 547 light-years from Earth and was discovered in 2025 using the radial velocity method.
Is TOI-1117 d in the Habitable Zone?
TOI-1117 d orbits inside the inner edge of the habitable zone of TOI-1117. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1117: 0.454–1.074 AU (conservative: 0.575–1.018 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1117 d
The equilibrium temperature of TOI-1117 d is about 978 K (705 °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 152 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-1117 d — one full orbit around TOI-1117 — lasts 8.66 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.082 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1117 d Discovered?
TOI-1117 d was discovered in 2025 using the radial velocity method, with observations from La Silla Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is TOI-1117 d?
TOI-1117 d is 546.6 light-years (167.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1480. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,620,160 years to make the journey.
The Host Star: TOI-1117
TOI-1117
- Spectral type
- G5 V
- Surface temperature
- 5,635 K (Sun: 5,772 K)
- Mass
- 0.97 M☉
- Radius
- 1.05 R☉
- Luminosity
- 0.3600 L☉
- Age
- 4.4 billion years (Sun: 4.6)
The TOI-1117 Planetary System
TOI-1117 d is one of 3 known planets in the TOI-1117 system. Its siblings:
- TOI-1117 b (Super Earth)
- TOI-1117 c (Super Earth)
TOI-1117 d — Complete Data
| Mass (best estimate) | 10.71 Earth masses |
|---|---|
| Orbital period | 8.66 days |
| Orbital distance | 0.082 AU |
| Equilibrium temperature | 978 K (705 °C) |
| Stellar irradiation | 152.00× Earth |
| Distance from Earth | 546.6 light-years (167.6 parsecs) |
| Constellation | Pavo |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-06-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1117 d
Is TOI-1117 d habitable?
No — TOI-1117 d orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1117 d?
TOI-1117 d is about 547 light-years from Earth in the constellation Pavo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,620,160 years to get there.
How long is a year on TOI-1117 d?
One orbit around TOI-1117 takes 8.7 Earth days — short enough that 42 of its years would fit into one Earth year.
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