First engulfed exoplanet not a victim of a bloated star after all
Two years ago it was said that a bloated star had swallowed an exoplanet for the first time. That was probably not true after all.
This is how the research group envisions the end of the exoplanet.
(Image: NASA, ESA, CSA, Ralf Crawford (STScI))
When a star was first observed devouring an exoplanet two years ago, it was probably not a glimpse of Earth's future after all. NASA reports that, contrary to initial assumptions, the star did not expand beforehand. Instead, the planet, which was doomed to die, had been moving closer and closer to it. Measurements with the James Webb Space Telescope (JWST) have now suggested this course of events. Eventually, the exoplanet began to graze the star's atmosphere. The uncontrollable process then accelerated and the planet was destroyed.
But no glimpse of the end of the Earth
The analysis is about a star 12,000 light years away from us, which has the designation ZTF SLRN-2020. When it was made public in May 2023 that it had devoured a planet, it was said that an increase in brightness in the optical spectrum had revealed the process. It was later determined that the flash of light had been preceded by a brightening in the infrared spectrum, by about a year. At the time, everything indicated that ZTF SLRN-2020 was a sun-like star that had grown to the size of a red giant at the end of its life and had devoured the planet in the process. Just as it will one day do with the sun.
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Subsequent measurements with the JWST's MIRI and NIRSpec instruments have now revealed a different history, writes NASA. The observation was so difficult because the star is located in a dense region of the sky and it was necessary to separate it and its immediate surroundings from the background. Only these measurements revealed that the star was not as bright as it should have been if it had blown up into a red giant. The swelling therefore did not take place at all. The planet must have fallen into the star by a different route. The team assumes that it has been moving closer and closer to the star on its orbit for millions of years.
The engulfed exoplanet was therefore about the size of Jupiter and orbited its star more closely than Mercury orbits the sun. When it finally crashed into it, it catapulted gas from the star's outer atmosphere into space, where it formed a cloud that slowly cooled down. The space telescope was even able to make out individual substances in it. The research team hopes that its work is not the end, but only the beginning of the exploration of the star system. For further measurements, they also want to use telescopes that are still being built. The researchers present their work in The Astropyhsical Journal.
(mho)
