Kepler-873 b
Kepler-873 b is a sub-Neptune orbiting Kepler-873 in the constellation Cygnus. It lies about 3,856 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is Kepler-873 b?
Kepler-873 b has a radius of 3.75 times that of Earth.
Is Kepler-873 b in the Habitable Zone?
The position of Kepler-873 b relative to the habitable zone of Kepler-873 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-873: 1.059–2.473 AU (conservative: 1.342–2.345 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-873 b — one full orbit around Kepler-873 — lasts 20.6 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-873 b Discovered?
Kepler-873 b was discovered in 2016 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-873 b?
Kepler-873 b is 3,855.9 light-years (1,182.2 parsecs) from Earth. Light arriving here tonight left the planet about 3,856 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 67,863,840 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. Kepler-873 b scores 0.20, ranking #3,844 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-873
Kepler-873
- Surface temperature
- 6,163 K (Sun: 5,772 K)
- Mass
- 1.18 M☉
- Radius
- 1.27 R☉
- Age
- 3.0 billion years (Sun: 4.6)
Planetary System
Kepler-873 b is the only planet known to orbit Kepler-873 so far.
Kepler-873 b — Complete Data
| Radius | 3.750 Earth radii (0.335 Jupiter radii) |
|---|---|
| Orbital period | 20.55 days |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 3,855.9 light-years (1,182.2 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-05-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-873 b
Is Kepler-873 b habitable?
Kepler-873 b is not known to orbit within the habitable zone of Kepler-873, and as a sub-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-873 b?
Kepler-873 b is about 3,856 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 67,863,840 years to get there.
How big is Kepler-873 b compared to Earth?
Kepler-873 b has 3.75 times the radius of Earth.
How long is a year on Kepler-873 b?
One orbit around Kepler-873 takes 20.6 Earth days — short enough that 18 of its years would fit into one Earth year.
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