Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Twin Keck Telescopes Probe Dual Dust Disks

Astronomers using the twin 10-meter telescopes at the W. M. Keck Observatory in Hawaii have explored one of the most compact dust disks ever resolved around another star. If placed in our own solar system, the disk would span about four times Earth’s distance from the sun, reaching nearly to Jupiter’s orbit. The compact inner disk is accompanied by an outer disk that extends hundreds of times farther.

The centerpiece of the study is the Keck Interferometer Nuller (KIN), a device that combines light captured by both of the giant telescopes in a way that allows researchers to study faint objects otherwise lost in a star’s brilliant glare. "This is the first compact disk detected by the KIN, and a demonstration of its ability to detect dust clouds a hundred times smaller than a conventional telescope can see," said Christopher Stark, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Md., who led the research team.

By merging the beams from both telescopes in a particular way, the KIN essentially creates a precise blind spot that blocks unwanted starlight but allows faint adjacent signals – such as the light from dusty disks surrounding the star – to pass through.

In April 2007, the team targeted 51 Ophiuchi, a young, hot, B-type star about 410 light-years away in the constellation Ophiuchus. Astronomers suspect the star and its disks represent a rare, nearby example of a young planetary system just entering the last phase of planet formation, although it is not yet known whether planets have formed there.

"Our new observations suggest 51 Ophiuchi is a beautiful protoplanetary system with a cloud of dust from comets and asteroids extremely close to its parent star," said Marc Kuchner, an astronomer at Goddard and a member of the research team.

Planetary systems are surprisingly dusty places. Much of the dust in our solar system forms inward of Jupiter's orbit, as comets crumble near the sun and asteroids of all sizes collide. This dust reflects sunlight and sometimes can be seen as a wedge-shaped sky glow – called the zodiacal light – before sunrise or after sunset.

Dusty disks around other stars that arise through the same processes are called "exozodiacal" clouds. "Our study shows that 51 Ophiuchi’s disk is more than 100,000 times denser than the zodiacal dust in the solar system," explained Stark." This suggests that the system is still relatively young, with many colliding bodies producing vast amounts of dust."

To decipher the structure and make-up of the star’s dust clouds, the team combined KIN observations at multiple wavelengths with previous studies from NASA’s Spitzer Space Telescope and the European Southern Observatory’s Very Large Telescope Interferometer in Chile.

The inner disk extends about 4 Astronomical Units (AU) from the star and rapidly tapers off. (One AU is Earth’s average distance from the sun, or 93 million miles.) The disk’s infrared color indicates that it mainly harbors particles with sizes of 10 micrometers – smaller than a grain of fine sand – and larger.

The outer disk begins roughly where the inner disk ends and reaches about 1,200 AU. Its infrared signature shows that it mainly holds grains just one percent the size of those in the inner disk – similar in size to the particles in smoke. Another difference: The outer disk appears more puffed up, extending farther away from its orbital plane than the inner disk.

"We suspect that the inner disk gives rise to the outer disk," explained Kuchner. As asteroid and comet collisions produce dust, the larger particles naturally spiral toward the star. But pressure from the star’s light pushes smaller particles out of the system. This process, which occurs in our own solar system, likely operates even better around 51 Ophiuchi, a star 260 times more luminous than the sun.

The findings appear in the October 1 issue of The Astrophysical Journal.

Francis Reddy | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht A new kind of quantum bits in two dimensions
19.03.2018 | Vienna University of Technology

nachricht 'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

A new kind of quantum bits in two dimensions

19.03.2018 | Physics and Astronomy

Scientists have a new way to gauge the growth of nanowires

19.03.2018 | Materials Sciences

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Science & Research
Overview of more VideoLinks >>>