Kepler-1787 b
Kepler-1787 b is a mini-Neptune orbiting Kepler-1787 in the constellation Cygnus. It lies about 2,540 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is Kepler-1787 b?
Kepler-1787 b has a radius of 2.32 times that of Earth.
Is Kepler-1787 b in the Habitable Zone?
The position of Kepler-1787 b relative to the habitable zone of Kepler-1787 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-1787: 0.751–1.756 AU (conservative: 0.951–1.665 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 ›
Orbit and Year Length
A year on Kepler-1787 b — one full orbit around Kepler-1787 — lasts 39.3 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-1787 b Discovered?
Kepler-1787 b was discovered in 2021 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 Kepler-1787 b?
Kepler-1787 b is 2,539.5 light-years (778.6 parsecs) from Earth. Light arriving here tonight left the planet about 2,540 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 44,695,200 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. Kepler-1787 b scores 0.32, ranking #1,038 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-1787
Kepler-1787
- Surface temperature
- 6,060 K (Sun: 5,772 K)
- Mass
- 1.01 M☉
- Radius
- 0.93 R☉
Planetary System
Kepler-1787 b is the only planet known to orbit Kepler-1787 so far.
Kepler-1787 b — Complete Data
| Radius | 2.319 Earth radii (0.207 Jupiter radii) |
|---|---|
| Orbital period | 39.31 days |
| Earth Similarity Index | 0.32 |
| Distance from Earth | 2,539.5 light-years (778.6 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-12-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-1787 b
Is Kepler-1787 b habitable?
Kepler-1787 b is not known to orbit within the habitable zone of Kepler-1787, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-1787 b?
Kepler-1787 b is about 2,540 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 44,695,200 years to get there.
How big is Kepler-1787 b compared to Earth?
Kepler-1787 b has 2.32 times the radius of Earth.
How long is a year on Kepler-1787 b?
One orbit around Kepler-1787 takes 39.3 Earth days.
Explore Kepler-1787 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
