CoRoT-2b

Lore & Background

CoRoT-2b was detected via the transit method, and its mass was later confirmed using the radial velocity method. The planet is a large hot Jupiter, with a radius about 1.43 times that of Jupiter and a mass approximately 3.3 times Jupiter's. Its extreme size is attributed to intense heating from its parent star, which causes the outer layers of its atmosphere to bloat. The planet's estimated temperature is around 1,500 K, even hotter than expected given its close orbit, possibly indicating tidal heating from interactions with another planet. At Jupiter-like distances, its radius would be roughly the same as Jupiter's. The complete phase curve of the planet has been observed.

The planet orbits its star once every 1.7 days in a prograde direction close to the star's equator. The parent star is a G-type star, slightly cooler than the Sun but more active, and is located about 800 light-years from Earth. The spin-orbit angle, measured via the Rossiter–McLaughlin effect, was initially calculated in 2008 as +7.2 ± 4.5°, and later revised in 2012 to 4.0°.

Reader's Guide

CoRoT-2b holds significance as one of the early exoplanets discovered by the CoRoT mission, demonstrating the mission's capability to detect transiting hot Jupiters. Its unusually large radius for its mass and orbital distance has made it a key object for studying atmospheric inflation and tidal heating mechanisms. The planet's extreme temperature, exceeding expectations, suggests additional heating sources beyond stellar irradiation, possibly from gravitational interactions with an unseen companion. The measurement of its spin-orbit angle, initially determined and later revised, provides insight into the system's dynamical history and the alignment between the star's equator and the planet's orbit. The observation of its complete phase curve has contributed to understanding the thermal structure and energy distribution of hot Jupiters. CoRoT-2b remains a benchmark for models of planetary evolution under intense stellar radiation and for the study of tidal effects in exoplanetary systems.

Did You Know?

• CoRoT-2b was the second extrasolar planet detected by the CoRoT mission.
• Its radius is 1.43 times that of Jupiter, but at Jupiter-like distances it would be roughly the same size.
• The planet's estimated temperature of 1,500 K is hotter than expected given its close orbit.
• The spin-orbit angle was revised from +7.2 ± 4.5° in 2008 to 4.0° in 2012.