KOI-1831 d
KOI-1831 d is a terrestrial planet orbiting Kepler-324 in the constellation Draco. It lies about 1,636 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is KOI-1831 d?
KOI-1831 d has a radius of 1.13 times that of Earth. Its mass is 2.2 times that of Earth, giving it a density of 9.95 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is KOI-1831 d in the Habitable Zone?
The position of KOI-1831 d relative to the habitable zone of Kepler-324 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-324: 0.527–1.264 AU (conservative: 0.667–1.198 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 KOI-1831 d
The equilibrium temperature of KOI-1831 d is about 475 K (202 °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.
Orbit and Year Length
A year on KOI-1831 d — one full orbit around Kepler-324 — lasts 34.2 Earth days, shorter than Mercury's 88-day year.
How Was KOI-1831 d Discovered?
KOI-1831 d was discovered in 2018 using the transit method, with observations from Kepler.
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 KOI-1831 d?
KOI-1831 d is 1,635.9 light-years (501.6 parsecs) from Earth. Light arriving here tonight left the planet about 1,636 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 28,791,840 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. KOI-1831 d scores 0.39, ranking #506 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-324
Kepler-324
- Surface temperature
- 5,194 K (Sun: 5,772 K)
- Radius
- 0.84 R☉
The Kepler-324 Planetary System
KOI-1831 d is one of 4 known planets in the Kepler-324 system. Its siblings:
- Kepler-324 b (Terrestrial)
- Kepler-324 c (Sub Neptune)
- Kepler-324 e (Mini Neptune)
KOI-1831 d — Complete Data
| Radius | 1.130 Earth radii (0.101 Jupiter radii) |
|---|---|
| Mass | 2.23 Earth masses (0.007 Jupiter masses) |
| Density | 9.95 g/cm³ (Earth: 5.51) |
| Orbital period | 34.17 days |
| Equilibrium temperature | 475 K (202 °C) |
| Earth Similarity Index | 0.39 |
| Distance from Earth | 1,635.9 light-years (501.6 parsecs) |
| Constellation | Draco |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2021-06-11. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About KOI-1831 d
Is KOI-1831 d habitable?
KOI-1831 d is not known to orbit within the habitable zone of Kepler-324, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is KOI-1831 d?
KOI-1831 d is about 1,636 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 28,791,840 years to get there.
How big is KOI-1831 d compared to Earth?
KOI-1831 d has 1.13 times the radius of Earth and about 2.2 times its mass.
How long is a year on KOI-1831 d?
One orbit around Kepler-324 takes 34.2 Earth days — short enough that 11 of its years would fit into one Earth year.
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