Kepler-1649c

Lore & Background

Kepler-1649c orbits its host star, an M-type red dwarf roughly one-quarter the radius of the Sun, at a distance of 0.0649 AU with an orbital period of about 19.5 Earth days. The star has only two confirmed planets, the other being Kepler-1649b, which is similar in size to Venus and orbits at roughly half the radius of Kepler-1649c's orbit. Based on its mass and radius, Kepler-1649c is likely a terrestrial planet, though its proximity to its star suggests it may be tidally locked.

The planet receives about three-quarters of the radiation from its host star that Earth receives from the Sun, which could allow surface temperatures similar to Earth's depending on atmospheric composition. However, due to the lack of information on its atmosphere, it is unclear if Kepler-1649c can sustain liquid water on its surface. No solar flare-ups have been observed from the host star as of 2021, but scientists believe such stars are prone to frequent flare activity that may have stripped the planet's atmosphere.

Orbital evolution models indicate that significant oscillations of eccentricity are likely under the mutual gravitational influence of Kepler-1649c, Kepler-1649b, and a postulated intermediate planet, but the climate would remain Earth-like for most initial parameters.

Reader's Guide

Kepler-1649c is notable for being described in 2017 by Jeff Coughlin, director of SETI's K2 Science Office, as the most 'similar planet to Earth' found so far by the Kepler Space Telescope. Its recovery from an initial false positive designation by the Kepler False Positive Working Group was published on April 15, 2020, and its first scientific description appeared in The Astrophysical Journal Letters with first author Andrew Vanderburg in April 2020.

The planet's significance lies in its combination of Earth-like size and location within the habitable zone of its star, making it a key target for studies of potentially habitable exoplanets. Its mass and radius suggest a rocky composition, and its stellar flux of 75% of Earth's raises the possibility of liquid water if an appropriate atmosphere exists. However, the lack of atmospheric data and the potential for stellar flares from its red dwarf host star leave its habitability uncertain. The planet is often compared to other potentially habitable worlds such as Kepler-62f, Kepler-186f, and TRAPPIST-1e, and contributes to the broader understanding of Earth analogs in red dwarf systems.

Did You Know?

• Its host star, Kepler-1649, is a red dwarf with roughly one-quarter the radius of the Sun.
• The planet's first scientific description was published in The Astrophysical Journal Letters in April 2020.