Astronomers spy proto-planetary hit-and-run

Have you seen this planetesimal?

By Lucy Sherriff • Get more from this author

Posted in Science, 14th January 2005 13:00 GMT

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Astronomers have spied evidence of planet formation occurring around nearby stars. Observers at the Gemini South 8-meter telescope in Chile, say details in the dusty disk around Beta Pictoris indicate collisions between planet-sized bodies have occurred as recently as in the last few decades.

The clump around Beta-pictoris where the suspected collision occurred

Dr. Charlie Telesco of the University of Florida, who led the team, commented: "Our research is a bit like a detective dusting for fingerprints to figure out a crime scene, only in this case we use the dust as a tracer to show what has happened within the cloud. The properties of the dust show not only that this was a huge collision, but that it probably happened recently in both astronomical and even on human timescales."

The observations, taken in the mid-infrared, reveal a higher concentration of fine particles of dust, rock and ice in one region of the disk. The debris has given the disk around the star a lopsided appearance. Scientists involved in the research say that dust this fine is dispersed quickly after a collision, suggesting that these are the remains of a relatively recent crash.

Collisions between planetesimals, large bodies of rock and ice, is thought to be behind the formation of the planets in our own solar system. This particular crash is thought to be of equivalent size to the incident that may have created our moon: a Mars sized body ran into what would become the Earth, and the moon was formed from the resulting debris.

Telesco went on: "It is as if we were looking back about five billion years and watching our own solar system as it was forming into what we see today." ®