Finding Planets is Easier than we Thought: Part Two – Less Dusty Sun-Like Stars

Yesterday I wrote about young stars that had a habitable zone further away than we thought, and how this would help us spot habitable planets more easily in the future.

Today is the second news story this week dealing with finding planets, and it deals with more familiar Sun-like stars and their dusty planetary discs.

Dust is both a good thing and a bad thing when looking for planets orbiting other stars.  Dust tells us that there is a high likelihood of finding planets, but too much dust blocks out the planets that we look for.  Warm dust is worse than cold dust as it glows in infrared and can block out any chance of finding a planet.

After surveying 50 stars with the Keck Interferometer from 2008 – 2011, Scientists at NASA’s Jet Propulsion Laboratory have concluded that, on average, sun-like stars just aren’t very dusty, which will make it a lot easier to see orbiting planets in the future.

Credit: NASA / JPL

The Keck Interferometer is designed to block out the light from stars, which blinds us from the light of any orbiting planets.  It does this by using two separate 10-meter telescopes to image the star, and cancel out the star’s light through a process called nulling, which reveals the dust close to the star, along with any planets.

“If you don’t turn off the star, you are blinded and can’t see dust or planets,” said co-author Rafael Millan-Gabet of NASA’s Exoplanet Science Institute at the California Institute of Technology in Pasadena.

The study is being used to survey candidate stars for future planet-hunting missions, both space-based and ground-based.  Astronomers want to avoid stars with lots of warm dust, as they reflect light in visible wavelengths and glow brightly in infrared wavelengths.  This can completely hide any habitable planets.

There may be new techniques in the future that can remove the mask of the dustier stars, but for now we have a good starting point in understanding which stars are worth a closer look.

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