Astronomers have discovered a faraway planet with a dusty tail.
In May 2012, researchers announced that they might have detected a disintegrating exoplanet. Roughly the size of Mercury, the planet – 1500 light-years from Earth – appeared to be being boiled away by the intense heat of its parent star.
Now, a different team has found evidence that suggests a massive dust cloud has been shed by the planet, similar to a comet’s tail. Both groups used observations from NASA’s Kepler space telescope, which locates alien planets by flagging brightness dips caused when they pass in front of their parent stars.
It lies very close to its host star –orbiting completely every 15 hours – and it is consequently incredibly hot: its surface temperature estimated to be around 1982 degrees Celsius.
In a previous study, it was observed that light coming from the planet’s host star KIC 12557548 dims in oddly variable ways which were dissimilar to other planet-hosting stars. The researchers theorised that the brightness dips are due to the planet being surrounded by a huge veil of dust and gas.
In this new study, the scientists found clear signals that KIC 12557548’s light is being scattered and absorbed by large amounts of dust.
“Some of this dust escapes into space, where the intense stellar radiation quickly evaporates it,” study lead author Matteo Brogi, of Leiden University in the Netherlands. “The variable amount of dust leads to the observed variability in the star’s dimming.”
Further work with even more sophisticated instruments could allow the researchers to determine what exactly the planet is made of.
“By observing the dust clouds in different colours, something Kepler cannot do, we will be able to determine the amount and the composition of the dust and estimate its lifetime,” said co-author Christoph Keller. “As the evaporation peels the planet like an onion, we can now see what used to be the inside of a planet.”
The study has been accepted for publication in the journal Astronomy & Astrophysics.