University of Arizona | Steward Observatory | 29 July 2010
The Gemini NICI Planet-Finding Campaign: Discovery of a Close SubstellarThe discovery is expected to shed light on the early stages of solar system formation.
An international team led by University of Hawaii astronomers Beth Biller and Michael Liu with help from University of Arizona astronomer Laird Close and UA graduate students Eric Nielsen, Jared Males and Andy Skemer made the rare find using the Near-Infrared Coronagraphic Imager, or NICI, on the international 8-meter Gemini-South Telescope in Chile.
What makes this discovery special is the proximity between the 36 Jupiter-mass brown dwarf companion, dubbed PZ Tel B, and its primary star, named PZ Tel A. They are separated by only 18 Astronomical Units, or AUs, similar to the distance between Uranus and the sun.
Most young brown dwarf and planetary companions found by direct imaging are at orbital separations greater than 50 AUs – larger than the orbit of Pluto, at 40 AUs.
In addition to its small separation, in just the past year the researchers observed PZ Tel B moving quickly outward from its parent star.
An older image, taken seven years ago and reanalyzed by Laird Close, a professor at UA's Steward Observatory and the department of astronomy, showed PZ Tel B was obscured by the glare from its parent star as recently as 2003, indicating its orbit is more elliptical than circular.
...
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 the sun). In fact, the PZ Tel system is young enough to still possess significant amounts of cold circumstellar dust, which may have been sculpted by the gravitational interaction with the young brown dwarf companion.
This makes the PZ Tel system an important laboratory for studying the early stages of solar system formation. With an estimated mass of 36 times that of Jupiter, PZ Tel B's orbital motion has significant implications for what type of planets can form (and whether planets can form at all) in the PZ Tel system.
...
The discovery of PZ Tel B is described in a paper being published by Astrophysical Journal Letters.
Companion to the Young Debris Disk Star PZ Tel - BA Biller et al
- arXiv.org > astro-ph > arXiv:1007.4808 >27 Jul 2010
