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<\/a><\/p>\nAn artist\u2019s impression of a Sun-like star engulfing a giant exoplanet. Image credit: International Gemini Observatory \/ NOIRLab \/ NSF \/ AURA \/ M. Garlick \/ M. Zamani<\/p>\n
Using data from NASA\u2019s Transiting Exoplanet Survey Satellite (TESS), astronomers Edward Bryant and Vincent Van Eylen looked at 456,941 stars that had just entered the post-main sequence phase.<\/p>\n
They used computer algorithm to search for the repeated dips in brightness that indicate an orbiting planet is passing in front of the star, focusing on giant planets with short orbital periods (i.e., that took no more than 12 days to orbit their star).<\/p>\n
They identified 130 planets and planet candidates, including 33 that were previously unknown, orbiting closely around these stars.<\/p>\n
They found such planets were less likely to occur around stars that had expanded and cooled enough to be classed as red giants (i.e. that were further on in their post-main sequence evolution), suggesting many of these planets may already have been destroyed.<\/p>\n
\u201cThis is strong evidence that as stars evolve off their main sequence they can quickly cause planets to spiral into them and be destroyed,\u201d said Dr. Bryant, an astronomer at University College London and the University of Warwick.<\/p>\n
\u201cThis has been the subject of debate and theory for some time but now we can see the impact of this directly and measure it at the level of a large population of stars.\u201d<\/p>\n
\u201cWe expected to see this effect but we were still surprised by just how efficient these stars seem to be at engulfing their close planets.\u201d<\/p>\n
\u201cWe think the destruction happens because of the gravitational tug-of-war between the planet and the star, called tidal interaction.\u201d<\/p>\n
\u201cAs the star evolves and expands, this interaction becomes stronger.\u201d<\/p>\n
\u201cJust like the Moon pulls on Earth\u2019s oceans to create tides, the planet pulls on the star.\u201d<\/p>\n
\u201cThese interactions slow the planet down and causing its orbit to shrink, making it spiral inwards until it either breaks apart or falls into the star.\u201d<\/p>\n
\u201cIn a few billion years, our own Sun will enlarge and become a red giant,\u201d said Dr. Van Eylen, an astronomer at University College London.<\/p>\n
\u201cWhen this happens, will the solar system planets survive? We are finding that in some cases planets do not.\u201d<\/p>\n
\u201cEarth is certainly safer than the giant planets in our study, which are much closer to their star.\u201d<\/p>\n
\u201cBut we only looked at the earliest part of the post-main sequence phase, the first one or two million years of it \u2014 the stars have a lot more evolution to go.\u201d<\/p>\n
\u201cUnlike the missing giant planets in our study, Earth itself might survive the Sun\u2019s red giant phase. But life on Earth probably would not.\u201d<\/p>\n