Kepler-62c

Lore & Background

Kepler-62c was discovered as part of the Kepler spacecraft's survey of stars in the Kepler Input Catalog. The spacecraft observed transits—periodic dimming events caused by a planet crossing in front of its star—occurring roughly every 12 days. These observations took place between 13 May 2009 and 17 March 2012. The planet's periodic transits led to the conclusion that a planetary body was responsible, and the discovery was announced on April 18, 2013, alongside the Kepler-69 system.

The planet orbits its host star at a distance of about 0.092 AU, receiving about 25 times more sunlight than Earth does from the Sun. Its equilibrium temperature is 578 K, and its radius of 0.54 R🜨 is comparable to Mars. The mass is not known, but an upper limit of <4 M🜨 is estimated, with the real mass expected to be significantly lower, around 0.1 M🜨, similar to Kepler-37b.

The host star Kepler-62 is a K-type star with a mass of 0.69 M☉, a radius of 0.64 R☉, a temperature of 4925 K, and an age of 7 billion years. It is somewhat metal-poor, with a metallicity of −0.37, or 42% of the solar amount. Its luminosity is 21% that of the Sun, and its apparent magnitude of 13.65 makes it too dim to be seen with the naked eye.

Reader's Guide

Kepler-62c is notable as one of the smallest exoplanets confirmed by the Kepler spacecraft at the time of its discovery, second only to Kepler-37b. Its Mars-sized radius and sub-Earth classification place it among the growing population of low-mass planets found by transit surveys. The planet's high stellar flux—25 times Earth's—and equilibrium temperature of 578 K make it similar to Mercury in terms of insolation, though its mass remains uncertain with an upper limit of <4 M🜨 and an expected value around 0.1 M🜨. The discovery of Kepler-62c, along with the other four planets in the Kepler-62 system, demonstrated the Kepler mission's ability to detect and confirm small planets in short-period orbits. The system's K-type host star, older and less luminous than the Sun, provides a contrasting environment for studying planetary formation and evolution. Kepler-62c's 12-day orbit at 0.092 AU highlights the diversity of planetary architectures, with multiple planets packed close to their star. The planet's confirmation via the transit method, using data collected over nearly three years, underscores the patience required to detect small, periodic signals. Its legacy lies in expanding the known range of exoplanet sizes and orbital configurations, contributing to the statistical understanding of planetary systems around low-mass stars.

Did You Know?

• Kepler-62c was the second-smallest exoplanet discovered and confirmed by the Kepler spacecraft at the time, after Kepler-37b.
• The planet's equilibrium temperature is 578 K, similar to Mercury.
• Its host star Kepler-62 is 7 billion years old, older than the Sun's 4.6 billion years.