Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ideas on gas-giant planet formation take shape

24.03.2006


Rocky planets such as Earth and Mars are born when small particles smash together to form larger, planet-sized clusters in a planet-forming disk, but researchers are less sure about how gas-giant planets such as Jupiter and Saturn form. Is core accretion--the process that creates their smaller, terrestrial cousins--responsible? Or could an alternate model known as disk instability--in which the planet-forming disk itself actually fragments into a number of planet-sized clumps--be at work? Could both be possible under different circumstances?



Recent work from the Carnegie Institution’s Department of Terrestrial Magnetism explores both possibilities. This and other relevant work regarding planet formation is presented at the NASA Astrobiology Science Conference (AbSciCon) 2006 at the Ronald Reagan Building in Washington, D.C. March 26-30. See http://abscicon2006.arc.nasa.gov/ for details.

Carnegie Fellow Hannah Jang-Condell1 has devised a method to catch the early stages of gas-giant core accretion in the act. If actively accreting cores exist, they should leave a gravitational "dimple" in the planet-forming disk--even if the cores are only a fraction the size of Jupiter. Since disk instability would result in planet-sized fragments straight away, the existence of these young, intermediate-sized cores would be a clear indicator of core accretion.


The telltale gravitational dimples resemble craters on the Moon with sunlight shining in from the side: the inside of the edge nearest the star is shadowed, while the star-facing edge is illuminated. The bright side heats up and the shadowed side remains cool, yielding a distinct thermal pattern that an Earth-based observer should be able to see in the infrared spectrum. "If we could detect this signature in a protoplanetary disk, it would indicate the presence of a young planetary body that could go on to form a gas-giant via core accretion," Jang-Condell said.

In some situations, however, core accretion seems an unlikely model for gas-giant planet formation. For example, theoretical computer models by DTM staff member Alan Boss2 suggest that disk instability best explains planet formation around M dwarf stars, which have masses from one tenth to one half that of the Sun. Core accretion would likely take more than 10 million years around these small, gravitationally weak stars, while disk instability happens quickly enough to yield gas-giant planets in as little as 1,000 years.

"M dwarf stars dominate the stellar population in the solar neighborhood, and so are attractive targets for searching for habitable planets," Boss said. "The models show that gas-giant planets are indeed likely to form…at distances sufficiently large enough to permit the later formation of habitable, terrestrial planets."

Other talks and posters on planet formation at the conference include: A study of organic matter in the planet-forming disks of three young stars, ranging in age from less than one million to over 300 million years3; methods to detect water ice, methane ice, and silicate dust in the planet-forming disks of distant stars4; and a method to deduce the composition of far-off planets based on their mass and radius5.

Alan Boss | EurekAlert!
Further information:
http://www.ciw.edu

More articles from Physics and Astronomy:

nachricht Space radiation won't stop NASA's human exploration
18.10.2017 | NASA/Johnson Space Center

nachricht Study shows how water could have flowed on 'cold and icy' ancient Mars
18.10.2017 | Brown University

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>