Kepler-223 d
Kepler-223 d is a Neptune-like planet orbiting Kepler-223 in the constellation Cygnus. It lies about 6,066 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-223 d?
Kepler-223 d has a radius of 5.24 times that of Earth. Its mass is 8.0 times that of Earth, giving it a density of 0.31 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is Kepler-223 d in the Habitable Zone?
The position of Kepler-223 d relative to the habitable zone of Kepler-223 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on Kepler-223 d — one full orbit around Kepler-223 — lasts 14.8 Earth days, shorter than Mercury's 88-day year. Its orbit is nearly circular (eccentricity 0.037).
How Was Kepler-223 d Discovered?
Kepler-223 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-223 d?
Kepler-223 d is 6,065.6 light-years (1,859.7 parsecs) from Earth. Light arriving here tonight left the planet about 6,066 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 106,754,560 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-223 d scores 0.15, ranking #4,198 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-223
Kepler-223
- Mass
- 1.13 M☉
- Radius
- 1.72 R☉
The Kepler-223 Planetary System
Kepler-223 d is one of 4 known planets in the Kepler-223 system. Its siblings:
- Kepler-223 b (Mini Neptune)
- Kepler-223 c (Puffy Planet)
- Kepler-223 e (Neptune-like)
Kepler-223 d — Complete Data
| Radius | 5.240 Earth radii (0.467 Jupiter radii) |
|---|---|
| Mass | 8.00 Earth masses (0.025 Jupiter masses) |
| Density | 0.31 g/cm³ (Earth: 5.51) |
| Orbital period | 14.79 days |
| Eccentricity | 0.037 |
| Earth Similarity Index | 0.15 |
| Distance from Earth | 6,065.6 light-years (1,859.7 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2016-08-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-223 d
Is Kepler-223 d habitable?
Kepler-223 d is not known to orbit within the habitable zone of Kepler-223, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is Kepler-223 d?
Kepler-223 d is about 6,066 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 106,754,560 years to get there.
How big is Kepler-223 d compared to Earth?
Kepler-223 d has 5.24 times the radius of Earth and about 8.0 times its mass.
How long is a year on Kepler-223 d?
One orbit around Kepler-223 takes 14.8 Earth days — short enough that 25 of its years would fit into one Earth year.
Explore Kepler-223 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.
