The planet orbits 4.5 times the Earth-Sun distance away from its star, and is almost 13 times the mass of Jupiter. Image Credit: Harvard-Smithsonian, Center for Astrophysics/D. A. Aguilar


A novel technique for detecting exoplanets could help astronomers find worlds with long years.

By combining information from the Kepler and Gaia space telescopes, the new method can reveal planets within months, rather than decades.

The new technique could expand the variety of planets we are able to discover.

Currently, the main technique used to find exoplanets is the transit method, where astronomers watch stars looking for a slight dip in brightness as a planet passes in front and blocks out the light.

However, it takes at least three transits to get enough data to be useful, and some planets can take years to complete a second or third orbit.

To put it in perspective, if an alien astronomer were trying to find Jupiter, they would have to wait over 30 years to get enough data.

A team at the University of Geneva solved this problem by combining the information of transit searches with observations by other telescopes.

The astronomers, led by exoplanet researcher Helen Giles from the University of Geneva, found a clear transit signal in observations of the star EPIC 248847494 taken by the Kepler space telescope.

Fortunately, this star was one of over a billion currently being observed by the Gaia satellite.

The team cross-referenced the two sets of data to find that a planet orbited the star at 4.5 times the Earth-Sun distance, taking 10 years to do so.

Further study with the Euler telescope in Chile allowed them to determine the planet’s mass was 13 times the mass of Jupiter.

The technique could now be used on other planetary systems, expanding the types of worlds we might find in the future.

“This technique could be used to hunt habitable, Earth-like planets around stars like the Sun,” says Helen Giles who led the study.


“In the future, we could even see if the planet has one or more moons, like our Jupiter.”


Elizabeth Pearson
Ezzy PearsonScience journalist

Ezzy Pearson is the Features Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.