CoRoT-7b — a rocky exoplanet with an ultra-short orbital period

Physical characteristics

Transit measurements give CoRoT-7b a radius roughly 1.5–1.7 times that of Earth, placing it in the class commonly called a "super-Earth." Combined photometric and spectroscopic work indicates a density consistent with a predominantly rocky composition rather than a large volatile envelope, though precise values and interpretations have evolved as new analyses appeared. Mass estimates derived from radial velocity data varied and at times were controversial because the host star shows magnetic activity that complicates measurements. For authoritative catalog and distance summaries see data and catalogs.

Discovery and measurement challenges

CoRoT-7b was detected by the transit method when periodic, shallow dips in the star's brightness were observed. Follow-up radial velocity observations were used to estimate the planet's mass, but stellar activity produced signals at similar amplitudes, making it difficult to separate planetary and stellar contributions. Because of these complications, researchers published a range of mass estimates and debated the best analysis techniques; later studies refined the values but emphasized remaining uncertainties. For details on the host star itself see CoRoT-7.

Orbit and environment

The planet completes a full orbit in about 20 hours, an ultra-short period that places it extremely close to its star. At this distance CoRoT-7b is expected to be tidally locked, with one hemisphere in permanent daylight and the opposite in permanent night. The dayside receives intense stellar irradiation, leading to very high surface temperatures and probable loss of any light atmosphere; some researchers have suggested molten surface conditions or a transient vapor atmosphere produced by rock evaporation. For background on orbital periods and dynamics see orbital period.

Significance

At the time of its announcement CoRoT-7b was one of the first small transiting planets with both radius and mass constraints, making it an important early example of a candidate rocky exoplanet. Its discovery demonstrated the ability of space photometry combined with ground-based spectroscopy to probe terrestrial-size worlds and helped motivate subsequent searches and follow-up strategies. It remains a touchstone in discussions of short-period super-Earths and extreme surface environments. For general discussion of rocky worlds see terrestrial planet.

Further reading and resources

This article is a summary; observational papers and mission pages provide expanded data and evolving parameter estimates. Consult mission archives and exoplanet databases for the most recent analyses, and overview material on the constellation Monoceros and broader exoplanet summaries at exoplanet and host star resources. Additional catalog entries and surveys are available through compilations referenced in general data and catalogs.

Note: links above point to placeholder resources; follow mission archives and peer-reviewed literature for primary sources. See also community databases and survey summaries linked from institutional pages and databases using the same catalogs referenced here at CoRoT-7 data.