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 Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>