Rotation Of Exoplanet Measured For First Time

Beta Pictoris b
Artist’s rendition of Beta Pictoris b orbiting its star. Credit: ESO L. Calçada/N. Risinger

Astronomers have determined the rotational speed of an exoplanet for the first time. Beta Pictoris b is an exoplanet orbiting the star Beta Pictoris 63 light-years away and one of the first exoplanets directly imaged by telescopes. Dutch astronomers using the European Southern Observatory’s Very Large Telescope (VLT) and a doppler-effect technique used to image the surface of stars have determined the gas giant rotates at almost 100,000 km/hr.

Beta Pictoris b is 3000 times the mass and sixteen times the size of Earth. For perspective, Earth’s rotational speed at the equator is only 1674.4 km/hr. Using this data, the length of Beta Pictoris b’s day is only 8 hours long.

The astronomers hope to further refine this technique to resolve features such as cloud patterns and storms.

A PDF of this research is available for download from ESO’s website.