From Bruce Denness, Whitwell, Isle of Wight, UK
Ryan MacDonald notes that in the early 1990s Michel Mayor and Didier Queloz were the first to observe an exoplanet around a sun-like star (10 November, p 38). It was thought to be a gaseous “hot Jupiter” orbiting eight times closer to its star, 51 Pegasi, than Mercury is from the sun.
Rocky planets are thought to have formed with gaseous mantles. These were then stripped away by an outflux of particles from their star – called a “T Tauri wind” after the star for which a class of young stars is named – during their solar system's infancy. If this is correct, how did the hot Jupiter close to 51 Pegasi avoid a similar fate? If it is wrong, could the rocky planets and the cores of the sun and Jovian planets (before they acquired their gas mantles) have been nomadic interstellar interlopers (17 November, p 19)?
