WASP-47 d
WASP-47 d is a sub-Neptune orbiting WASP-47 in the constellation Aquarius. It lies about 864 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is WASP-47 d?
WASP-47 d has a radius of 3.65 times that of Earth. Its mass is 15.5 times that of Earth.
Is WASP-47 d in the Habitable Zone?
The position of WASP-47 d relative to the habitable zone of WASP-47 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on WASP-47 d — one full orbit around WASP-47 — lasts 9.03 Earth days, shorter than Mercury's 88-day year. Its orbit is nearly circular (eccentricity 0.001).
How Was WASP-47 d Discovered?
WASP-47 d was discovered in 2015 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 WASP-47 d?
WASP-47 d is 863.6 light-years (264.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1163. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 15,199,360 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. WASP-47 d scores 0.20, ranking #3,906 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-47
WASP-47
- Mass
- 1.06 M☉
- Radius
- 1.16 R☉
The WASP-47 Planetary System
WASP-47 d is one of 4 known planets in the WASP-47 system. Its siblings:
WASP-47 d — Complete Data
| Radius | 3.650 Earth radii (0.326 Jupiter radii) |
|---|---|
| Mass | 15.50 Earth masses (0.049 Jupiter masses) |
| Orbital period | 9.03 days |
| Eccentricity | 0.001 |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 863.6 light-years (264.8 parsecs) |
| Constellation | Aquarius |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2024-08-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-47 d
Is WASP-47 d habitable?
WASP-47 d is not known to orbit within the habitable zone of WASP-47, and as a sub-Neptune it is an unlikely candidate for life as we know it.
How far away is WASP-47 d?
WASP-47 d is about 864 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 15,199,360 years to get there.
How big is WASP-47 d compared to Earth?
WASP-47 d has 3.65 times the radius of Earth and about 15.5 times its mass.
How long is a year on WASP-47 d?
One orbit around WASP-47 takes 9.0 Earth days — short enough that 40 of its years would fit into one Earth year.
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