BULLETIN

Hot Neptune found around bright star

Discovery raises puzzle of how planet held onto its atmosphere

The discovery of a Neptune-sized planet around a hot, bright star could help astronomers understand the mysterious lack of Neptune-sized worlds in tight orbits, a phenomenon known as the Hot Neptune Desert.

Though current detection methods mean most exoplanets we know of are close to their stars and larger than Jupiter, it’s thought that if a small world gets too close to a star, the radiation will strip its atmosphere away.

To test this, Courtney Dressing from the University of California, Berkeley looked for Neptune-sized worlds around A-type stars, which are much brighter in ultraviolet than other types of star. “If we’re able to look at planets receiving different amounts of light from their star, especially different wavelengths of light, then we can try to see how exactly a planet keeps its atmosphere over time,” says Dressing. www.berkeley.edu