Scientists ferret out planet-hunting targets with NASA telescope

April 8th, 2011 - 7:10 pm ICT by ANI  

Washington, April 8 (ANI): US astronomers have discovered a new technique to identify close, faint stars using NASA’s Galaxy Evolution Explorer satellite.

The technique would help in the hunt for planets that lie beyond our solar system, because nearby, hard-to-see stars could very well be home to the

easiest-to-see alien planets.

The glare of bright, shining stars has frustrated most efforts at visualizing distant worlds. So far, only a handful of distant planets, or exoplanets, have been directly imaged.

Small, newborn stars are less blinding, making the planets easier to see, but the fact that these stars are dim means they are hard to find in the first place.

Fortunately, the young stars emit more ultraviolet light than their older counterparts, which makes them conspicuous to the ultraviolet-detecting Galaxy Evolution Explorer.

“We’ve discovered a new technique of using ultraviolet light to search

for young, low-mass stars near the Earth,” said David Rodriguez, a graduate student of astronomy at UCLA.

“These young stars make excellent targets for future direct imaging of exoplanets,” he said.

Rodriguez and his team compared readings from the telescope with optical and infrared data to look for the telltale signature of rambunctious junior stars.

Follow-up observations of 24 candidates identified in this manner determined that 17 of the stars showed clear signs of youth, validating the team’s approach.

“The Galaxy Evolution Explorer can readily select young, low-mass stars that are too faint to turn up in all-sky X-ray surveys, which makes the telescope an incredibly useful tool,” said Rodriguez.

Astronomers call the low-mass stars in question “M-class” stars. Also known as red dwarfs, these stars glow a relatively cool crimson color compared to the hotter oranges and yellows of stars like our Sun, and the whites and blues of the most scorching stars.

With data from the Galaxy Evolution Explorer, astronomers could reap a bounty of these red dwarfs still in their cosmic youth, under 100 million years old.

In many ways, these stars represent a best-case scenario for the direct imaging of exoplanets. They are close and in clear lines-of-sight, which generally makes viewing easier.

Their low mass means they are dimmer than heavier stars, so their light is less likely to mask the feeble light of a planet. And because they are young stars, their planets are freshly formed, and thus warmer and brighter than older planetary bodies.

The new study was published in the February issue of The Astrophysical

Journal. (ANI)

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