Astronomers have announced the possible discovery of the first known moon outside our Solar System.
This “exomoon” is not like any in our cosmic neighbourhood: it’s the size of Neptune and orbits a planet the size of Jupiter – but with 10 times the mass.
The object was spotted in data from Nasa’s Kepler spacecraft, and later observed using the Hubble telescope.
Astronomers David Kipping and Alex Teachey have published their results in Science Advances journal.
But they say that further observations are needed to understand the distant planetary system.
“We’ve tried our best to rule out other possibilities such as spacecraft anomalies, other planets in the system or stellar activity, but we’re unable to find any other single hypothesis which can explain all of the data we have,” said Dr Kipping, from Columbia University in New York.
To date, astronomers have discovered more than 3,500 exoplanets – worlds orbiting stars other than the Sun.
A hunt for exomoons – bodies that orbit these distant planets – has proceeded in parallel. But so far, these natural satellites have lingered at the limits of detection with current techniques.
The researchers monitored a planet known as Kepler 1625b as it passed in front of its parent star.
This 19-hour event, known as a transit, blocked out some of the light coming from the star, which lies at a distance of 8,000 light-years from Earth.
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SOURCE: BBC News, Paul Rincon