TRAPPIST-1c

Template:Planetbox begin Template:Planetbox image Template:Planetbox star Template:Planetbox orbit Template:Planetbox character Template:Planetbox discovery Template:Planetbox end TRAPPIST-1c, also designated as 2MASS J23062928-0502285 c, is an exoplanet orbiting around the ultracool dwarf star TRAPPIST-1 approximately 40 light-years away from Earth in the constellation Aquarius. It is by far the most massive planet of the system at 1.63 Earth masses. However, in terms of radius, it is only the second largest, being slightly smaller than TRAPPIST-1g. The planet was discovered by the transit method and first announced on May 2, 2016. While cool enough to retain a significant atmosphere, it is considered too hot to be habitable.

Characteristics

Mass, radius, and temperature

TRAPPIST-1c is a roughly Earth-sized planet. It has a radius of about 1.056 Earth radii, based on the amount of starlight it blocked. The planet's mass was determined by transit-timing variation, which shows the gravitational influence between transiting planets. TRAPPIST-1c was originally thought to have 1.38 times the mass of Earth, but more recent estimates place it at around 1.63 Earth masses with less uncertainty. This makes TRAPPIST-1c the largest planet in the system in terms of mass. With a density of 7.63 g/cm³ (~1.38 times the density of Earth) and a gravitational pull of ~1.462g, it is likely that TRAPPIST-1c is an iron planet.

Habitability

It is possible that water loss occurred prior to the dimming of the planet's star. It was estimated that TRAPPIST-1b and TRAPPIST-1c may have lost up to 15 Earth oceans, likely compromising their habitability. However, with an equilibrium temperature of over 341.9 kelvins (68.75 °C, 155.75 °F), any water remaining would have boiled off, but truly not enough to boil fresh water.