Featured Research

from universities, journals, and other organizations

Scientists help define structure of exoplanets

Date:
February 1, 2012
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
Using models similar to those used in weapons research, scientists may soon know more about exoplanets, those objects beyond the realm of our solar system. Astronomers have come up with new methods for deriving and testing the equation of state of matter in exoplanets and figured out the mass-radius and mass-pressure relations for materials relevant to planetary interiors.

The planet GJ 1214b, shown here in an artist's conception with two hypothetical moons, orbits a "red dwarf" star 40 light-years away from Earth.
Credit: Center for Astrophysics/David Aguilar

Using models similar to those used in weapons research, scientists may soon know more about exoplanets, those objects beyond the realm of our solar system.

In a new study, Lawrence Livermore National Laboratory scientists and collaborators came up with new methods for deriving and testing the equation of state (EOS) of matter in exoplanets and figured out the mass-radius and mass-pressure relations for materials relevant to planetary interiors.

Astronomers started detecting exoplanets 18 years ago and more than 700 have been found so far, the vast majority within the last two years. Interest is now growing in the structure and atmospheres of these worlds.

New equation-of-state work helps interpret the structure of exoplanets. As there is a minimal amount of data in each exoplanet observation, interpretation of their composition and structure depends largely on comparing their mass and radius with the composition expected given the distance from their parent star. The makeup implies a mass-radius relation, which relies heavily on EOS calculated from electronic structure theory and measured experimentally on Earth.

In the new research, lead Laboratory scientist Damian Swift, along with LLNL colleagues Jon Eggert, Damien Hicks, Sebastien Hamel, Kyle Caspersen, Eric Schwegler and Rip Collins, compared their modeling results with the observed masses and radii of exoplanets. Their results broadly support recent assumptions about the structures of exoplanets but can now take advantage of the accurate EOS models and data produced at Livermore.

"Current theoretical techniques for calculating electronic structures can predict EOS relevant to planetary interiors," Swift said. "But we still need experimental validation of these calculations; something that can now be done at the National Ignition Facility (NIF)."

LLNL's National Ignition Facility is the world's largest laser designed to perform research on national security, fusion experimentation and basic science, such as astrophysics.

The team made specific predictions for notable exoplanets having earth-like, rocky, icy compositions, with planetary center pressures ranging from 8 to 19,000 Mbar (8 million to 1.9 billion atmospheres of pressure).

"We have a project to measure material properties up to billions of atmospheres on NIF. We will eventually exceed the highest pressures investigated in the very small number of previous experiments using underground nuclear tests, which reached far above pressures that can be explored with other techniques currently available," Swift said.

Placing constraints on the structure of exoplanets requires accurate information about the compressibility of relevant compositions of matter, including iron alloys, silicates, and ices, under extreme conditions of pressure and temperature.

"This sets the record straight and presents a survey of exoplanet structure information using material properties generated for, and validated using, experimental capabilities at the national labs," Swift said.

Other collaborators include the University of Rostock and the University of Edinburgh. The research recently appeared in The Astrophysical Journal.

The research was funded by LLNL's Laboratory Research and Development program. LDRD is used to fund creative basic and applied research activities in areas aligned with the Lab's principal missions.


Story Source:

The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. C. Swift, J. H. Eggert, D. G. Hicks, S. Hamel, K. Caspersen, E. Schwegler, G. W. Collins, N. Nettelmann, G. J. Ackland. Mass-Radius Relationships for Exoplanets. The Astrophysical Journal, 2012; 744 (1): 59 DOI: 10.1088/0004-637X/744/1/59

Cite This Page:

DOE/Lawrence Livermore National Laboratory. "Scientists help define structure of exoplanets." ScienceDaily. ScienceDaily, 1 February 2012. <www.sciencedaily.com/releases/2012/02/120201140014.htm>.
DOE/Lawrence Livermore National Laboratory. (2012, February 1). Scientists help define structure of exoplanets. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/02/120201140014.htm
DOE/Lawrence Livermore National Laboratory. "Scientists help define structure of exoplanets." ScienceDaily. www.sciencedaily.com/releases/2012/02/120201140014.htm (accessed October 21, 2014).

Share This



More Space & Time News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com
Latin America Launches Communications Satellite

Latin America Launches Communications Satellite

AFP (Oct. 17, 2014) Argentina launches a home-built satellite, a first for Latin America. It will ride a French-made Ariane 5 rocket into orbit, and will provide cell phone, digital TV, Internet and data services to the lower half of South America. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
This Week @ NASA, October 17, 2014

This Week @ NASA, October 17, 2014

NASA (Oct. 17, 2014) Power spacewalk, MAVEN’s “First Light”, Hubble finds extremely distant galaxy and more... Video provided by NASA
Powered by NewsLook.com
Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Newsy (Oct. 17, 2014) The smallest of Saturn's main moons, Mimas, wobbles as it orbits. Research reveals it might be due to a global ocean underneath its icy surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins