Space and Physics

How 'Death Stars' wipe out potential planets


Janet Fang

Staff Writer

clockMar 11 2014, 04:48 UTC
407 How 'Death Stars' wipe out potential planets
Artist's depiction of two protostars around a massive O-type star. Dust and gas around the nearer proplyd will be blasted away by the radiation from the star. The farther proplyd is able to retain its planet-making potential. NRAO/AUI/NSF; B. Saxton
Hundreds of young stars and protostars reside in the Orion Nebula, swathed by dust and gas. For many of these stars, the material surrounding them will go on to form planets. But others will have all of their planet-forming dust and gas blasted away by “Death Stars” taking the form of massive O-type stars, a new study shows
Sun-like stars are often born in crowded stellar nurseries like the Orion Nebula. Over millions of years, specks of dust and pockets of gas combine into larger, denser bodies. Many will grow into full-fledged star systems, complete with orbiting planets. But not all stars have planets, and this research shows one reason why that is true.
To study the sometimes-deadly relationship between protostars and their much bigger stellar neighbors, a team of astronomers used Atacama Large Millimeter/submillimeter Array (ALMA) to look at dozens of embryonic stars with planet-forming potential. They found evidence, for the first time, that protoplanetary disks (also called proplyds) simply vanished under the intense glow of a neighboring massive star, Rita Mann of the National Research Council (NRC) of Canada says in a press release
In just a few million years, the fierce ultraviolet radiation emitted by highly luminous O-type stars can blow away the planet-forming potential any proplyds that are within a 0.1 light-year radius -- the distance of the massive star’s extreme-UV envelope. Hundreds of times more luminous than our Sun, these O-type stars deplete nearby protoplanetary disks by heating up the gas, breaking it up, and sweeping it away, NRC’s James Di Francesco explains. In the end, the newborn star might be left with a fraction of the material necessary to create even a single Jupiter-sized planet. 
"O-type stars, which are really monsters compared to our Sun, emit tremendous amounts of ultraviolet radiation and this can play havoc during the development of young planetary systems," Mann says. But it’s all part of the circle of galactic life. When massive yet short-lived stars explode as supernovas, they seed the surrounding area with dust and heavy elements that will go on to form the next generation of stars. 
The work was published in the Astrophysical Journal this week. 
Image: NRAO/AUI/NSF; B. Saxton

Space and Physics
  • protostars,

  • protoplanetary,

  • proplyds,

  • Orion