Kepler-281 d
Kepler-281 d is a Neptune-like planet orbiting Kepler-281 in the constellation Cygnus. It lies about 5,693 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is Kepler-281 d?
Kepler-281 d has a radius of 5.94 times that of Earth, or 0.53 times the radius of Jupiter.
Is Kepler-281 d in the Habitable Zone?
The position of Kepler-281 d relative to the habitable zone of Kepler-281 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-281: 0.664–1.567 AU (conservative: 0.841–1.486 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-281 d — one full orbit around Kepler-281 — lasts 148.3 Earth days, between the years of Mercury (88 days) and Earth (365 days).
How Was Kepler-281 d Discovered?
Kepler-281 d 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-281 d?
Kepler-281 d is 5,692.9 light-years (1,745.5 parsecs) from Earth. Light arriving here tonight left the planet about 5,693 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 100,195,040 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-281 d scores 0.32, ranking #1,031 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-281
Kepler-281
- Surface temperature
- 5,723 K (Sun: 5,772 K)
- Radius
- 0.90 R☉
The Kepler-281 Planetary System
Kepler-281 d is one of 3 known planets in the Kepler-281 system. Its siblings:
- Kepler-281 b (Mini Neptune)
- Kepler-281 c (Neptune-like)
Kepler-281 d — Complete Data
| Radius | 5.937 Earth radii (0.530 Jupiter radii) |
|---|---|
| Orbital period | 148.27 days |
| Earth Similarity Index | 0.32 |
| Distance from Earth | 5,692.9 light-years (1,745.5 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-281 d
Is Kepler-281 d habitable?
Kepler-281 d is not known to orbit within the habitable zone of Kepler-281, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is Kepler-281 d?
Kepler-281 d is about 5,693 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 100,195,040 years to get there.
How big is Kepler-281 d compared to Earth?
Kepler-281 d has 5.94 times the radius of Earth.
How long is a year on Kepler-281 d?
One orbit around Kepler-281 takes 148.3 Earth days.
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