Science & Environment

Planets stripped bare by host stars

Artist's impression of planet having atmosphere stripped Image copyright Peter Devine

Astronomers have confirmed the existence of planets that have had their atmospheres stripped away by their host stars.

Planets with atmospheres that orbit too close to their host stars are bombarded by a torrent of high-energy radiation.

The gaseous outer layers of these worlds are then stripped away, according to the international team of scientists.

Their work appears in the journal Nature Communications.

The researchers used data from Nasa's Kepler space telescope, which was launched to identify and study exoplanets, which circle stars other than our own.

They focused on a category of planet called "super Earths", which are roughly 2-10 times more massive than our own planet.

Co-author Dr Guy Davies, from the University of Birmingham, said: "For these planets it is like standing next to a hairdryer turned up to its hottest setting.


The astronomers used a technique called asteroseismology, which probes the internal structure of stars, to confirm the idea.

By characterising the host star, the team was able to also determine the precise sizes of the exoplanets around them.

The results of the study have important implications for understanding how stellar systems, like our own Solar System, and their planets, evolved over time - including the role played by the host star.
