Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers will use neon to track planet formation with neon

13.09.2007
Astronomers have observed neon in disks of dust and gas swirling around sunlike stars for the first time.

University of Arizona astronomers who collaborated in the observations say that neon could show which stars retain their surrounding dust-and-gas disks needed to form planets and which stars might already have formed planets.

"When I saw the neon, I couldn't believe it. I was just amazed," said UA Steward Observatory astronomer Ilaria Pascucci. "We were not expecting to see neon around low-mass stars like our sun."

Pascucci is a co-investigator on a Spitzer Space Telescope Legacy project called "Formation and Evolution of Planetary Systems, known as FEPS, headed by Steward Observatory's Michael R. Meyer. The project used an infrared spectrometer to conduct a sensitive search for planet-forming gas around 35 young, solar analog stars.

Neon showed up in disks of four sunlike stars in Spitzer's FEPS data. The discovery was a surprise because "we didn't realize that solar analog stars could radiate enough high-energy (X-ray and ultraviolet) light to ionize neon," Pascucci said.

"Astronomers have used ionized neon for years to study massive star formation, novae and the galactic center, all places where the environment is energetic and harsh, so it was a surprise to find this neon emission from planet-forming stars like the sun," Meyer said. "It serves as a valuable reminder that the environment in which the planets formed was harsh, too, in a way. And it could turn out to be an important tracer of remnant gas in circumstellar disks ­ a kind of 'vacancy/no vacancy' sign for planets."

Neon -- a gas commonly used in outdoor advertising signs since the 1920s -- is one of the few chemical elements that doesn't chemically react to form molecules or condense into solid particles. There's not much of it in Earth's atmosphere, only about 18 parts per million. Nor is it plentiful in gas whirling around stars, Pascucci said.

But when a neon atom absorbs high-energy X-ray or ultraviolet light, it "ionizes," or becomes electrically charged, and gives off infrared light at specific wavelengths. The Spitzer Space Telescope saw the spectral line at

12.8 microns, one of neon's infrared signatures.

So although neon isn't an abundant gas, it is pure, and it radiates infrared light at specific wavelengths when it ionizes, making it useful for tracing planet formation.

Most gas in the disk surrounding a star is swept up by the central star itself. Much of the remaining gas becomes so hot and energetic that it "photoevaporates," or escapes the star system's powerful gravity and evaporates into space. Scientists suspect that if too much gas photoevaporates too quickly, a star has missed its chance to form gas-giant planets.

Scientists believe that planets form when dust particles in the disk around a star begin to stick together and continue to grow by clumping, or "accreting," over millions of years. Some of these planetary building blocks smash together, eventually creating rocky planets like Earth or the cores of gas-giant planets like Jupiter. Ever-larger planetary cores exert greater gravity. If a core becomes massive enough, its gravity becomes powerful enough to pull in gas from the protoplanetary disk, creating an atmosphere.

Gas in the disk may also play a crucial role in making planets suitable for life, Pascucci said. The gas may help to circularize the orbits of planets as they form, as well as provide atmospheres for rocky Earthlike planets and gas-giant planets. Both the orbit of a planet and its atmosphere play an important role in stabilizing climate, a big factor in whether complex life can form and survive.

Astronomers may be able to trace the gas that is needed to circularize the orbits of Earthlike planets in the terrestrial planet region with neon, she added.

Pascucci and the FEPS team published their results in the July 2007 edition of Astrophysical Journal.

Pascucci will make future observations that use neon to track gas content in disks around young stars at different stages of planet formation using NASA's Spitzer Space Telescope and the Very Large Telescope, or the VLT, in Chile.

"We'll use the Spitzer to look for neon in disks around slightly older systems than we've studied so far," Pascucci said. "Because neon is tracing a very tiny amount of gas mass, we want to see how the gas dissipates with time."

Some of the gas lines are strong enough that astronomers will be able to see the spectra from the ground with the VLT. Pascucci and her colleagues will study 15 candidate objects using the VLT in February 2008. The ground-based telescope is far less sensitive to infrared light than is Spitzer, but it is 50 times higher velocity resolution than the space telescope. By clocking the speed of the gas, the VLT should be able to locate where the gas is within a disk.

"The two studies are very complementary," Pascucci said. "Once we know for a sample of stars where the gas emission is coming from (using the VLT), we then can extrapolate to other stars which Spitzer can see.

"Nobody thought about observing these types of lines from the ground before they were detected by Spitzer. At least, I wasn't thinking about detecting neon," she added.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington.

Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

Contact Info:
Ilaria Pascucci 520-626-5909 pascucci@as.arizona.edu Michael Meyer 617-495-7380 mmeyer@as.arizona.edu

Lori Stiles | University of Arizona
Further information:
http://uanews.org

More articles from Physics and Astronomy:

nachricht CCNY-Yale researchers make shape shifting cell breakthrough
12.12.2018 | City College of New York

nachricht Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor
11.12.2018 | Science China Press

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: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

New discoveries predict ability to forecast dementia from single molecule

12.12.2018 | Health and Medicine

CCNY-Yale researchers make shape shifting cell breakthrough

12.12.2018 | Physics and Astronomy

Pain: Perception and motor impulses arise in the brain independently of one another

12.12.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>