Comet crystals feel the heat

Since comets formed out in the cold depths of the Solar System, the existence of materials in them that must have been created in high temperatures has been a real puzzle, until now. NASA’s Spitzer Space Telescope has observed the infrared signature of tiny silicate crystals, of the type found in comets, being created in the planet-forming disc around a young star called EX Lupi, in the constellation of Lupus.

The stellar outbursts occur when the growing young star accumulates a large amount of mass from the dusty, gaseous disc that is spinning around it. Each outburst sends a flash of heat permeating through the disc. At the distance the crystals were seen at, the temperature reached 725 degrees Celsius (about 1,000 kelvin), enough to thermally ‘anneal’ the silicate dust.