Length of exoplanet day measured for first time

Observations from ESO's Very Large Telescope have, for the first time, determined the rotation rate of an exoplanet. Beta Pictoris b has been found to have a day that lasts eight hours. This is quicker than any planet in the Solar System. This result extends the relation between mass and rotation seen in the Solar System to exoplanets. Similar techniques will allow mapping exoplanets in detail with the European Extremely Large Telescope.