{"id":151594,"date":"2021-11-10T07:00:02","date_gmt":"2021-11-10T17:00:02","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=151594"},"modified":"2021-11-09T16:36:10","modified_gmt":"2021-11-10T02:36:10","slug":"new-method-to-detect-tatooine-like-planets-validated","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2021\/11\/10\/new-method-to-detect-tatooine-like-planets-validated\/","title":{"rendered":"New method to detect Tatooine-like planets validated"},"content":{"rendered":"Reading time: <\/span> 3<\/span> minutes<\/span><\/span>
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This artist\u2019s rendering of the TIC<\/abbr> 172900988 circumbinary planetary system shows the two suns orbited by the detected planet. The size of the Earth\u2019s orbit is shown for comparison.<\/figcaption><\/figure>\n

A new technique developed in part by University of Â鶹´«Ã½<\/span> astronomer Nader Haghighipour<\/strong> has allowed scientists to quickly detect a transiting planet with two suns.<\/p>\n

Termed circumbinary planets, these objects orbit around a pair of stars. For years, these planets were merely the subject of science fiction, like Tatooine in Star Wars<\/em>. However, thanks to NASA<\/abbr>\u2019s successful planet-hunting Kepler and Transiting Exoplanet Survey Satellite (TESS<\/abbr>) missions, a team of astronomers, including Haghighipour, have found 14 such bodies so far.<\/p>\n

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Artist’s rendition of the Kepler-47 circumbinary planet system with its three planets. (Image courtesy of NASA<\/abbr>\/JPL<\/abbr>-Caltech\/T. Pyle)<\/figcaption><\/figure>\n

Kepler and TESS<\/abbr> detect planets via the transit method, where astronomers measure the tiny dimming of a star as a planet passes in front of its host star, blocking some of the starlight. Usually, astronomers need to see at least three of these transits to pin down the planet\u2019s orbit. This becomes challenging when there are two host stars.<\/p>\n

“Detecting circumbinary planets is much more complicated than finding planets orbiting single stars. When a planet orbits a double-star system, transits of the same star don\u2019t occur at consistent intervals,” explained Haghighipour. “The planet might transit one star, and then transit the other, before transiting the first star again, and so on.”<\/p>\n

Adding to the challenge, the orbital periods of circumbinary planets are always much longer than the orbital period of the binary star. That means, in order to observe three transits, scientists need to observe the binary for a long time. While that was not a problem with the Kepler space telescope (this telescope observed only one region of the sky for 3.5 years), it makes it challenging to use the TESS<\/abbr> telescope to detect circumbinary planets, because TESS<\/abbr> observes one portion (or sector) of the sky for only 27 days before pointing someplace else, making it impossible to observe three transits of a planet with TESS<\/abbr>.<\/p>\n