Terrestrial planet · GJ 9827

GJ 9827 b

ExoplanetsDiscovered 2017

Scientific overview

GJ 9827 b is a terrestrial planet orbiting GJ 9827, completing an orbit every 1.209 days, about 97 light-years from Earth. It was discovered in 2017 using the transit method.

Host star

GJ 9827

Spectral type

K7 V

Temperature

4,236 K

Mass

0.62 M☉

Planetary system — GJ 9827 system

View the GJ 9827 system (3 known planets).

Planet	Class	Radius (R⊕)	Period (d)	Distance (ly)
GJ 9827 bTransit · 2017	Terrestrial planet	1.44	1.209	97
GJ 9827 cTransit · 2017	Terrestrial planet	1.13	3.6481	97
GJ 9827 dTransit · 2017	Super-Earth	1.98	6.2018	97

Discovery and detection

Detection method

Transit Method

Discovery year

2017

Discovered at

Kepler Space Telescope

Knowledge connections

OrbitsGJ 9827
Member of systemGJ 9827 system
Discovered by methodTransit Method
Discovered by missionKepler Space Telescope
Catalogued inNASA Exoplanet Archive

Quick facts

Class: Terrestrial planet
Host star: GJ 9827
Discovery method: Transit Method
Discovery year: 2017
Orbital period: 1.209 d
Semi-major axis: 0.0189 AU
Eccentricity: 0
Radius: 1.44 R⊕
Mass: 4.28 M⊕
Density: 7.90 g/cm³ · derived
Equilibrium temp.: 1035 K
Insolation: 318 S⊕
Distance: 97 ly

Density is derived from the archive mass and radius via ρ = M / (4⁄3·π·r³); all other values are catalogued measurements.

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

Bulk density7.90 g/cm³derived
Formula & inputs
Formula: ρ = M / (4⁄3·π·r³) (v1.0.0, impl v1.0.0)
Inputs:
- massEarth = 4.28 M⊕ · NASA
- radiusEarth = 1.44 R⊕ · NASA
Assumptions: M⊕ = 5.972e+24 kg, R⊕ = 6371000 m (IAU 2015 B3 nominal); Assumes a uniform sphere.
Limitations: Withheld above 30 g/cm³ (inconsistent mass/radius inputs).; Archive mass/radius carry no propagated uncertainty here.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.

Quality & authority

Partial

Unreviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: None
Citation coverage: None
Image coverage: Not applicable

Data from the NASA Exoplanet Archive. See source quality.