G 9-40 b

G 9-40 b is a sub-Neptune exoplanet that has an orbital period of 5.7 days. The host star is a red dwarf located 91 light-years (28 parsecs) away from Earth in the constellation Cancer.^[4] The planet was discovered in 2019.^[5][6] The planet's density is too low for a rocky composition, suggesting that it is either water-rich or has a significant hydrogen atmosphere.^[3]

G 9-40 b

Discovery[1]
Discovery date	December 2019
Detection method	radial velocity and transit
Designations
Alternative names	K2-313 b[2]
Orbital characteristics[3]
Semi-major axis	0.04180±0.00064 AU
Eccentricity	0
Orbital period (sidereal)	5.7459982(20) d
Inclination	89.03°±0.10°
Physical characteristics[3]
Mean radius	1.900±0.065 R🜨
Mass	4.00±0.63 M🜨
Mean density	3.20+0.63 −0.58 g/cm3
Surface gravity	10.8±1.8 m/s2
Temperature	440.6±7.6 K (167.5 °C; 333.4 °F, equilibrium)

See also

• List of exoplanets discovered in 2019