Kepler-305 d
Kepler-305 d is a mini-Neptune orbiting Kepler-305 in the constellation Cygnus. It lies about 2,833 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-305 d?
Kepler-305 d has a radius of 2.76 times that of Earth. Its mass is 6.2 times that of Earth, giving it a density of 1.63 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is Kepler-305 d in the Habitable Zone?
The position of Kepler-305 d relative to the habitable zone of Kepler-305 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on Kepler-305 d — one full orbit around Kepler-305 — lasts 16.7 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-305 d Discovered?
Kepler-305 d was discovered in 2014 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-305 d?
Kepler-305 d is 2,832.6 light-years (868.5 parsecs) from Earth. Light arriving here tonight left the planet about 2,833 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 49,853,760 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-305 d scores 0.27, ranking #2,637 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-305
Kepler-305
- Mass
- 0.76 M☉
- Radius
- 0.80 R☉
The Kepler-305 Planetary System
Kepler-305 d is one of 4 known planets in the Kepler-305 system. Its siblings:
- Kepler-305 b (Puffy Planet)
- Kepler-305 c (Puffy Planet)
- Kepler-305 e (Super Earth)
Kepler-305 d — Complete Data
| Radius | 2.760 Earth radii (0.246 Jupiter radii) |
|---|---|
| Mass | 6.20 Earth masses (0.020 Jupiter masses) |
| Density | 1.63 g/cm³ (Earth: 5.51) |
| Orbital period | 16.74 days |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 2,832.6 light-years (868.5 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2024-06-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-305 d
Is Kepler-305 d habitable?
Kepler-305 d is not known to orbit within the habitable zone of Kepler-305, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-305 d?
Kepler-305 d is about 2,833 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 49,853,760 years to get there.
How big is Kepler-305 d compared to Earth?
Kepler-305 d has 2.76 times the radius of Earth and about 6.2 times its mass.
How long is a year on Kepler-305 d?
One orbit around Kepler-305 takes 16.7 Earth days — short enough that 22 of its years would fit into one Earth year.
Explore Kepler-305 d in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
