TRAPPIST-1f

TRAPPIST-1f, also known as 2MASS J23062928-0502285 f, is an exoplanet, potentially icy or likely rocky but under a massive water-steam gaseous envelope at very high pressure and temperature, orbiting within the habitable zone^[1] around the ultracool dwarf star TRAPPIST-1 40 light-years (12 parsecs) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.

TRAPPIST-1f

Artist's impression of TRAPPIST-1f. (February 2018)
Discovery
Discovery date	22 February 2017
Detection method	Transit
Orbital characteristics
Semi-major axis	0.037 AU (5,500,000 km)
Eccentricity	< 0.063
Orbital period	9.206690 (± 0.000015) d
Inclination	89.680 (± 0.034)
Star	TRAPPIST-1
Physical characteristics
Mean radius	1.045 (± 0.038) REarth
Mass	0.68 (± 0.18) M🜨
Surface gravity	~0.62 g
Temperature	Teq: 219 K (−54 °C; −65 °F) ≳1,400 K (1,130 °C; 2,060 °F) (surface)[2]

It was one of four new exoplanets to be discovered orbiting TRAPPIST-1 using observations from the Spitzer Space Telescope.^[3]

The planet is a eyeball planet candidate.