K2-219 d
K2-219 d is a mini-Neptune orbiting K2-219 in the constellation Pisces. It lies about 1,061 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is K2-219 d?
K2-219 d has a radius of 2.58 times that of Earth.
Is K2-219 d in the Habitable Zone?
The position of K2-219 d relative to the habitable zone of K2-219 cannot be precisely determined from the available orbital data.
Habitable zone of K2-219: 0.886–2.089 AU (conservative: 1.122–1.981 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 K2-219 d — one full orbit around K2-219 — lasts 11.1 Earth days, shorter than Mercury's 88-day year.
How Was K2-219 d Discovered?
K2-219 d was discovered in 2018 using the transit method, with observations from K2.
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 K2-219 d?
K2-219 d is 1,061.3 light-years (325.4 parsecs) from Earth. Light arriving here tonight left the planet about 1,061 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 18,678,880 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. K2-219 d scores 0.24, ranking #3,400 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-219
K2-219
- Surface temperature
- 5,753 K (Sun: 5,772 K)
- Mass
- 1.02 M☉
- Radius
- 1.19 R☉
The K2-219 Planetary System
K2-219 d is one of 3 known planets in the K2-219 system. Its siblings:
K2-219 d — Complete Data
| Radius | 2.576 Earth radii (0.230 Jupiter radii) |
|---|---|
| Orbital period | 11.14 days |
| Earth Similarity Index | 0.24 |
| Distance from Earth | 1,061.3 light-years (325.4 parsecs) |
| Constellation | Pisces |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2018-02-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-219 d
Is K2-219 d habitable?
K2-219 d is not known to orbit within the habitable zone of K2-219, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is K2-219 d?
K2-219 d is about 1,061 light-years from Earth in the constellation Pisces. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 18,678,880 years to get there.
How big is K2-219 d compared to Earth?
K2-219 d has 2.58 times the radius of Earth.
How long is a year on K2-219 d?
One orbit around K2-219 takes 11.1 Earth days — short enough that 33 of its years would fit into one Earth year.
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