Astronomers have directly imaged a very young brown dwarf (or failed star) in a tight orbit around a young nearby Sun-like star. An international team led by 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 using the Near-Infrared Coronagraphic Imager (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. Both are separated by only 18 Astronomical Units (AU), similar to the distance between Uranus to our Sun. Most young brown dwarf and planetary companions found by direct imaging are at orbital separations greater than 50 AU -- larger than the orbit of Pluto (40 AU). In addition to its small current 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/department of astronomy, showed PZ Tel B was completely obscured by the glare from its parent star as recently as 2003, indicating its orbit is more elliptical than circular.
“Because PZ Tel A is a rare star being both close and very young, it had been imaged several times in the past” said Laird Close. “So we were quite surprised to see a new companion around what was thought to be a single star.”
Lead author and UA graduate Beth Biller said: "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.”
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). 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.
Because PZ Tel B is so close to its parent star, special techniques are necessary to distinguish the faint light of the companion from the light of the primary star. PZ Tel B is separated by about 0.33 arcseconds from PZ Tel A, equivalent to a dime seen at a distance of 7 miles (11 km). In order to take pictures so close to the star, the team used an adaptive optics system coupled to a coronagraph in order to block out excess starlight, and then applied specialized analysis techniques to the images to detect PZ Tel B and measure its orbital motion.
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. NICI can detect companions 1 million times fainter than the host star at just 1 arcsecond separations. An international team of researchers drawn from across the Gemini Telescope community is currently carrying out a 300-star survey with NICI, the largest high contrast imaging survey conducted to date.
NICI Campaign leader Michael Liu says: "We are just beginning to glean the many configurations of solar systems around stars like the Sun. The unique capabilities of NICI provide us with a powerful tool for studying their constituents using direct imaging.”
This research was supported by grants from the National Science Foundation and NASA. NICI is a facility instrument at the Gemini Telescope http://www.gemini.edu/sciops/?q=sciops ).
Laird Close, University of Arizona, Department of Astronomy, email@example.com
Daniel Stolte, University of Arizona Office of Communications, (520) 626-4402; firstname.lastname@example.orgLINKS:
Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)
Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences