One of the central reasons exoplanets around distant stars can be so hard to spot directly is because the light of their parent star is so much brighter than the light being reflected by the plant it tends to block them from view. Scientists at Australian National University (ANU) have come up with a new optical chip that can be used with a telescope to help resolve the picture.
Few of the exoplanets discovered over the past two decades have been directly imaged with a telescope. Most have been found using other indirect techniques, such as Doppler spectroscopy, which is a way of analyzing a star's "wobble" caused by the gravitational pull of orbiting planets, or the transit method, where the small drop in brightness as a planet passes, or transits, in front of the star is detected.
ANU Associate Professor Steve Madden likens the new optical chip to working in a similar fashion to noise-canceling headphones, but for light instead of sound.
"This chip is an interferometer that adds equal but opposite light waves from a host sun, which cancels out the light from the (exoplanet's) sun, allowing the much weaker planet light to be seen," explains Madden.
The chip also helps spot young planets surrounded by clouds of dust, much like thermal imaging technology used by firefighters to see through smoke, which will help in searching for exoplanets that could support life.
"The chip uses the heat emitted from the planet to peer through dust clouds and see planets forming," explained Kenchington Goldsmith from the ANU Research School of Physics and Engineering. "Ultimately the same technology will allow us to detect ozone on alien planets that could support life."
Other efforts are also seeking to use leading-edge technology to get a direct glance at distant planets by blocking out the overpowering light from their host stars. Project Blue hopes to use a coronagraph to do just that and get a good look at our nearest exoplanet neighbor, Proxima B, in the coming decade.
The ANU team's research is being presented this week at the Australian Institute of Physics Congress.
Source: Australian National University
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