Tuesday, September 27, 2016

Icy Comets Orbiting a Star Like Our Sun Spotted for the First Time

Icy Comets Orbiting a Star Like Our Sun Spotted for the First Time

Amanda Smith, University of Cambridge

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For the first time, a ring of ice and comets orbiting a sun-like star has been spotted by an international team of astronomers led by the University of Cambridge. The report announced today at a conference in Santiago, Chile states that the dust ring is 160 light-years away from Earth, with gas concentration similar to the amount of the comets in our own solar system.

Analysis of the data from the Atacama Large Millimeter Array (ALMA) in Chile reveals that this belt of asteroids and comets contains the lowest carbon monoxide concentration detected. This could shed light on the formation of our own solar system.

Apparently, the system to which the comets belong to is only 23 million years old whereas our solar system is already 4.6 billion years old, bringing us closer to understanding the properties of comet clouds around sun-like stars just after they formed.

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ALMA image of the ring of comets around HD 181327 (colours have been changed). The white contours represent the size of the Kuiper Belt in the Solar System. Credit: Amanda Smith, University of Cambridge

The study, to be published in Monthly Notices of the Royal Astronomical Society, involved assessing the signatures of gas, which is produced by comets and asteroids slamming into each other and possibly with other planets. According to lead author Sebastián Marino, a Ph.D. student from Cambridge’s Institute of Astronomy, the belt of comets and asteroids belong to a very active system that has similar ice composition of our own solar system.

“The amount of gas we detected is analogous to a 200-kilometre diameter ice ball, which is impressive considering how far away the star is,” adds co-investigator co-author Luca Matrà, also a Ph.D. student at Cambridge’s Institute of Astronomy. “It’s amazing that we can do this with exoplanetary systems now.”

The star in question is HD 181327, located in the Painter constellation with a mass 30 percent greater than the sun. The astronomers speculate that the star could have planets orbiting around it but using better telescopes, which are currently unavailable, is needed to confirm this.

“Assuming there are planets orbiting this star, they would likely have already formed,” adds Matrà. “But the only way to see them would be through direct imaging, which at the moment can only be used for very large planets like Jupiter.”