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The Habitable Planet Finder is a new tool to locate Earth-like exoplanets

The Habitable Planet Finder, shown here at the Hobby-Eberly Telescope at McDonald Observatory in Texas, is normally covered with a lid that maintains a vacuum seal. The two objects on the far end are the large spectrometer mirrors that direct and format light from M-dwarf stars. The cylinder on the right is the camera, which focuses the light onto the infrared detector, a device that records it as a digital image. Gudmundur Stefansson / Pennsylvania State University

Astronomers have a new tool to help them find habitable planets in our galaxy: the Habitable Planet Finder (HPF), a high-precision spectrograph. The HPF can be used to detect worlds which have some key qualities, like being a rocky planet orbiting an red dwarf. A red dwarf, also known as an M-dwarf, is a type of star that is relatively cool, small, and dim, and is somewhat similar to our Sun (which is classified as a white or yellow dwarf.) Red dwarfs are common in the Milky Way, like the nearby Barnard’s star, making them good hunting grounds for exoplanets.

“About 70 percent of the stars in our galaxy are M-dwarfs like Barnard’s star, but the near-infrared light they emit has made it difficult for astronomers to see their planets with ordinary optical telescopes,” Paul Robertson, assistant professor of physics and astronomy at the University of California, Irvine, said in a statement. “With the HPF, it’s now open season for exoplanet hunting on a greatly expanded selection of stellar targets.”

The HPF measures subtle changes in the color of light given off by stars, which can indicate the influence of an orbiting planet. In particular, it searches for planets with a low mass located within the “habitable zone” of their stars where surface water can exist. The spectrograph has already demonstrated its usefulness by confirming the existence of a super-Earth which is orbiting Barnard’s star during its commissioning, and should be able to detect many more planets similar in size to Earth in the future.

“The project proved to us that the HPF has the capability to detect Earth-mass planets around other M-dwarf stars,” Robertson said in the same statement. “To me, that’s the most exciting thing about this result.”

The research is published in the journal Optica.

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