2MASS J04070752+1546457 (abbreviated to 2MASS J0407+1546) is a rapidly-rotating brown dwarf of spectral class L3.5, located in the constellation Taurus about 119 light-years from Earth. With a photometrically measured rotation period of 1.23 hours, it is one of the fastest-rotating known brown dwarfs announced by a team of astronomers led by Megan E. Tannock in March 2021. With a rotational velocity of over 80 km/s (50 mi/s), it is approaching the predicted rotational speed limit beyond which it would break apart due to centripetal forces. As a consequence of its rapid rotation, the brown dwarf is slightly flattened at its poles to a similar degree as Saturn, the most oblate planet in the Solar System. Its rapid rotation may enable strong auroral radio emissions via particle interactions i