GJ 9404 b
GJ 9404 b is a Neptune-like planet orbiting GJ 9404 in the constellation Coma Berenices. It lies about 78 light-years from Earth and was discovered in 2023 using the radial velocity method.
Is GJ 9404 b in the Habitable Zone?
The position of GJ 9404 b relative to the habitable zone of GJ 9404 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on GJ 9404 b — one full orbit around GJ 9404 — lasts 13.5 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.094 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.49), swinging dramatically closer to and farther from its star.
How Was GJ 9404 b Discovered?
GJ 9404 b was discovered in 2023 using the radial velocity method, with observations from Roque de los Muchachos Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is GJ 9404 b?
GJ 9404 b is 77.9 light-years (23.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1949. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,371,040 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. GJ 9404 b scores 0.28, ranking #2,281 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 9404
GJ 9404
- Mass
- 0.62 M☉
Planetary System
GJ 9404 b is the only planet known to orbit GJ 9404 so far.
GJ 9404 b — Complete Data
| Mass (best estimate) | 11.90 Earth masses |
|---|---|
| Orbital period | 13.46 days |
| Orbital distance | 0.094 AU |
| Eccentricity | 0.490 |
| Earth Similarity Index | 0.28 |
| Distance from Earth | 77.9 light-years (23.9 parsecs) |
| Constellation | Coma Berenices |
| Discovery method | Radial Velocity |
| Discovery facility | Roque de los Muchachos Observatory |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-09-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 9404 b
Is GJ 9404 b habitable?
GJ 9404 b is not known to orbit within the habitable zone of GJ 9404, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is GJ 9404 b?
GJ 9404 b is about 78 light-years from Earth in the constellation Coma Berenices. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,371,040 years to get there.
How long is a year on GJ 9404 b?
One orbit around GJ 9404 takes 13.5 Earth days — short enough that 27 of its years would fit into one Earth year.
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