Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Warped Debris Disks Around Stars Are Blowin’ in the Wind

31.08.2009
The dust-filled disks where new planets may be forming around other stars occasionally take on some difficult-to-understand shapes. Now, a team led by John Debes at NASA's Goddard Space Flight Center in Greenbelt, Md., finds that a star's motion through interstellar gas can account for many of them.

"The disks contain small comet- or asteroid-like bodies that may grow to form planets," Debes said. "These small bodies often collide, which produces a lot of fine dust." As the star moves through the galaxy, it encounters thin gas clouds that create a kind of interstellar wind. "The small particles slam into the flow, slow down, and gradually bend from their original trajectories to follow it."

Far from being empty, the space between stars is filled with patchy clouds of low-density gas. When a star encounters a relatively dense clump of this gas, the resulting flow produces a drag force on any orbiting dust particles. The force only affects the smallest particles -- those about one micrometer across, or about the size of particles in smoke.

"This fine dust is usually removed through collisions among the particles, radiation pressure from the star's light and other forces," explained Debes. "The drag from interstellar gas just takes them on a different journey than they otherwise would have had."

The inner, yellow portion of HD 61005's disk spans 5.4 billion miles, or about the width of Neptune's orbit in our own solar system. This false-color Hubble view masks the star's direct light to bring out detail in the disk. Credit: NASA/ESA/D. Hines (Space Science Inst., New Mexico) and G. Schneider (Univ. of Arizona) Working with Alycia Weinberger at the Carnegie Institution of Washington and Goddard astrophysicist Marc Kuchner, Debes was using the Hubble Space Telescope to investigate the composition of dust around the star HD 32297, which lies 340 light-years away in the constellation Orion. He noticed that the interior of the dusty disk -- a region comparable in size to our own solar system -- was warped in a way that matched a previously known warp at larger distances.

"Other research indicated there were interstellar gas clouds in the vicinity," Debes said. "The pieces came together to make me think that gas drag was a good explanation for what was going on."

"It looks like interstellar gas helps young planetary systems shed dust much as a summer breeze helps dandelions scatter seeds," Kuchner said.

As dust particles respond to the interstellar wind, a debris disk can morph into peculiar shapes determined by the details of its collision with the gas cloud. In a face-on encounter, such as that of the star HD 61005 in the constellation Puppis, the disk's edge bends gently away from the direction of motion. Fine dust trails behind, forming a cylindrical wake. If the disk instead slices edgewise through interstellar gas, the resulting headwind blows away fine dust from the portion inside the cloud, resulting in a lop-sided disk.

"The drag from interstellar gas only affects the outskirts of the disk, where the star's gravity can't really hold onto the material," Weinberger said.

The systems studied are about 100 million years old and resemble our own solar system shortly after the major planets formed. Although astronomers don't know whether planets lurk within the disks of these systems, a better understanding of processes affecting a disk's outer regions will shed light on how "ice giant" planets like Uranus and Neptune -- and the more distant swarm of small, icy bodies known as the Kuiper Belt -- formed within the solar system.

Astronomers have sometimes attributed warps and bends in debris disks to the presence of undiscovered planets or to past encounters with another star. "But we expect interstellar gas to be around -- it's everywhere," Debes said. "It's important to consider the ecology of these debris disks before running to such conclusions, and this model explains a lot of the weirdly shaped disks we see."

A paper describing the model appears in the September 1 issue of The Astrophysical Journal.

Related link:

NASA Supercomputer Shows How Dust Rings Point to Exo-Earths
http://www.nasa.gov/centers/goddard/news/topstory/2008/dust_rings.html

Francis Reddy | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/centers/goddard/news/topstory/2008/dust_rings.html

More articles from Physics and Astronomy:

nachricht APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science

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: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>