Artist’s impression of grains in the disc around a brown dwarf

Rocky planets are thought to form through the random collision and sticking together of what are initially microscopic particles in the disc of material around a star. These tiny grains, known as cosmic dust, are similar to very fine soot or sand. Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have for the first time found that the outer region of a dusty disc encircling a brown dwarf — a star-like object, but one too small to shine brightly like a star — also contains millimetre-sized solid grains like those found in denser discs around newborn stars. The surprising finding challenges theories of how rocky, Earth-scale planets form, and suggests that rocky planets may be even more common in the Universe than expected.

This artist’s impression first shows the disc of material around a brown dwarf, and then zooms in to show how tiny grains collide and stick together, to form large grains.


ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO)/M. Kornmesser (ESO) Music: movetwo

About the Video

Release date:30 November 2012, 12:00
Related releases:eso1248
Duration:48 s
Frame rate:30 fps

About the Object

Name:ISO-Oph 102



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