{"id":170615,"date":"2022-12-19T08:47:35","date_gmt":"2022-12-19T18:47:35","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=170615"},"modified":"2026-04-17T12:15:46","modified_gmt":"2026-04-17T22:15:46","slug":"planet-spiraling-to-its-doom","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2022\/12\/19\/planet-spiraling-to-its-doom\/","title":{"rendered":"Planet spiraling to its doom discovered by UH<\/abbr> astronomers"},"content":{"rendered":"
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\"Planet
Illustration of Kepler-1658 system (Image credit: Gabriel Perez Diaz\/Instituto de Astrof\u00edsica de Canarias)<\/figcaption><\/figure>\n

For the first time, astronomers have spotted an exoplanet with a decaying orbit around a star that resembles a future version of our Sun. The doomed world is destined to spiral closer and closer to its maturing star until they collide and the planet is obliterated.<\/p>\n

The planet, Kepler-1658b, with a mass and size similar to that of Jupiter, is familiar to University of Hawai\u02bbi<\/span> astronomers, who discovered it in 2019. The new findings, published in The Astrophysical Journal Letters<\/a>, now show that the orbital period of the planet is slowly decreasing, this can help astronomers better understand the fate of planets in the Solar System, since the Sun is expected to eventually evolve in a similar manner.<\/p>\n

\u201cWe had checked for evidence of this inward migration in the original discovery paper but could not definitively make that claim with only four years of data. therefore, it\u2019s somewhat validating to see that our expectations were correct,\u201d said UH<\/abbr> Institute for Astronomy<\/a> (IfA<\/abbr>) alumna Ashley Chontos<\/strong> who is now a postdoctoral fellow at Princeton University. Chontos led the discovery of the planet as part of her dissertation research at UH<\/abbr> M\u0101noa and is a co-author on the new study.<\/p>\n

Kepler-1658b orbits its host star at only an eighth of the distance between our Sun and its closest planet, Mercury. For planets such as Kepler-1658b that are already very close to their stars, orbital decay looks certain to culminate in destruction.<\/p>\n

Death-by-star<\/h2>\n

Measuring the orbital decay of exoplanets is difficult because the process is very gradual. According to the new study, Kepler-1658b\u2019s orbital period is decreasing at the miniscule rate of about 131 milliseconds (thousandths of a second) per year, with a shorter orbit indicating the planet has moved closer to its star. The discovery offers new insights into the lengthy process of planetary orbital decay, by providing the first look at a system at this late stage of evolution. Death-by-star is a fate thought to await many worlds, and could be the Earth’s ultimate outcome billions of years from now as the Sun grows older.<\/p>\n

\u201cThe ultimate fate of exoplanets is uncertain, but this system provides a crucial example for testing theories,\u201d said Nick Saunders<\/strong>, a graduate student at IfA<\/abbr> who co-authored the study. \u201cBy measuring the decay of the planet’s orbit, we gain valuable insight into how exoplanetary systems evolve and eventually come to an end.\u201d Saunders is leading a search for more planets orbiting evolved stars for his dissertation.<\/p>\n