Do Brown Dwarfs Pulsate?
By Ken Croswell Published on Astronomy.com (February 11, 2005). Brown dwarfs should pulsate when they’re young, predict astronomers in Italy and France. Such pulsations may already have been detected in Orion. Brown dwarfs are born with too little mass–less than 8 percent of the Sun’s–to sustain the fusion of hydrogen-1, the nuclear reaction powering main-sequence stars like the Sun. Brown dwarfs still shine, though, chiefly by transforming gravitational energy into heat. When young, they also generate energy by converting deuterium into helium-3. Deuterium is hydrogen-2, the rare heavy isotope of hydrogen. Deuterium fusion should cause brown dwarfs and very-low-mass red dwarfs to pulsate, say Francesco Palla of the Arcetri Astrophysical Observatory in Italy and Isabelle Baraffe at the Astronomical Research Center of Lyon in France. They will present their idea in a future issue of the journal Astronomy and Astrophysics. Deuterium burns at a cooler temperature than ordinary hydrogen,
