TOI-1260 d
TOI-1260 d is a sub-Neptune orbiting TOI-1260 in the constellation Ursa Major. It lies about 240 light-years from Earth and was discovered in 2022 using the transit method.
How Big Is TOI-1260 d?
TOI-1260 d has a radius of 3.12 times that of Earth. Its mass is 11.8 times that of Earth, giving it a density of 2.14 g/cm³ — between that of rocky and gaseous planets.
Is TOI-1260 d in the Habitable Zone?
TOI-1260 d orbits inside the inner edge of the habitable zone of TOI-1260. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1260: 0.290–0.725 AU (conservative: 0.367–0.687 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Temperature on TOI-1260 d
The equilibrium temperature of TOI-1260 d is about 499 K (226 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 10.32 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-1260 d — one full orbit around TOI-1260 — lasts 16.6 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.112 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1260 d Discovered?
TOI-1260 d was discovered in 2022 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
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-1260 d?
TOI-1260 d is 240.0 light-years (73.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1786. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,224,000 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-1260 d scores 0.31, ranking #1,108 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1260
TOI-1260
- Surface temperature
- 4,227 K (Sun: 5,772 K)
- Mass
- 0.68 M☉
- Radius
- 0.67 R☉
- Luminosity
- 0.1290 L☉
- Age
- 6.7 billion years (Sun: 4.6)
The TOI-1260 Planetary System
TOI-1260 d is one of 3 known planets in the TOI-1260 system. Its siblings:
- TOI-1260 b (Super Earth)
- TOI-1260 c (Super Earth)
TOI-1260 d — Complete Data
| Radius | 3.120 Earth radii (0.278 Jupiter radii) |
|---|---|
| Mass | 11.84 Earth masses (0.037 Jupiter masses) |
| Density | 2.14 g/cm³ (Earth: 5.51) |
| Orbital period | 16.61 days |
| Orbital distance | 0.112 AU |
| Equilibrium temperature | 499 K (226 °C) |
| Stellar irradiation | 10.32× Earth |
| Earth Similarity Index | 0.31 |
| Distance from Earth | 240.0 light-years (73.6 parsecs) |
| Constellation | Ursa Major |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2022-12-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1260 d
Is TOI-1260 d habitable?
No — TOI-1260 d orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1260 d?
TOI-1260 d is about 240 light-years from Earth in the constellation Ursa Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,224,000 years to get there.
How big is TOI-1260 d compared to Earth?
TOI-1260 d has 3.12 times the radius of Earth and about 11.8 times its mass.
How long is a year on TOI-1260 d?
One orbit around TOI-1260 takes 16.6 Earth days — short enough that 22 of its years would fit into one Earth year.
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