Brown dwarf star found orbiting a young sun-like star

July 30th, 2010 - 12:48 pm ICT by ANI  

Washington, July 30 (ANI): Astronomers have discovered a very young brown dwarf (or failed star dubbed “PZ Tel B”) in a tight orbit around a young nearby Sun-like star (PZ Tel A).

University of Hawaii astronomers Beth Biller and Michael Liu with help from University of Arizona astronomer Laird Close with UA graduate students Eric Nielsen, Jared Males and Andy Skemer made the rare find.

PZ Tel B was discovered using Near-Infrared Coronagraphic Imager (NICI), the most powerful high-contrast instrument designed for imaging brown dwarfs and extrasolar planets around other stars.

Both are separated by only 18 Astronomical Units (AU), similar to the distance between Uranus and our Sun.

The host star, PZ Tel A, is a younger version of the Sun, having a similar mass but a very young age of only 12 million years (about 400 times younger than our Sun).

Most young brown dwarf and planetary companions found by direct imagings are at orbital separations greater than 50 AU — larger than the orbit of Pluto (40 AU).

“Because PZ Tel A is a rare star being both close and very young, it had been imaged several times in the past” said Close.

“So we were quite surprised to see a new companion around what was thought to be a single star,” Close added.

“PZ Tel B travels on a particularly eccentric orbit — in the last 10 years, we have literally watched it careen through its inner solar system. This can best be explained by a highly eccentric, or oval-shaped, orbit,” said Biller.

“The unique capabilities of NICI provide us with a powerful tool for studying their constituents using direct imaging,” said NICI Campaign leader Michael Liu. (ANI)

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