Observations with the SPHERE instrument on ESO’s Very Large Telescope (VLT) in Chile have revealed a hidden Jupiter-like planet orbiting the star AF Leporis, 87.5 light-years away.

Image: Direct Images Of The Planet Orbiting AF Leporis. – ESO/MESA, DE ROSA ET AL.

Two groups of astronomers led by Dino Mesa (INAF, Italy) and Robert De Rosa (ESO, Chile) studied star catalogs obtained with the Hipparcos and Gaia satellites of the European Space Agency.

Over the years, these two space missions have accurately identified the position and motion of the stars in our galaxy with the technique of astrometry. Planets exert a gravitational tug on their host stars, disturbing their path in the sky. The two teams found that the star AF Leporis exhibited an altered trajectory, a telltale sign that a planet might be hidden.

As the two groups took a closer look at this system with the VLT, they managed to obtain direct images of the planet orbiting AF Leporis, the ESO reports in a statement. Both used the SPHERE instrument, which corrects for blur caused by atmospheric turbulence using adaptive optics, and also blocks the light from the star with a special mask, revealing the presence of the nearby planet. They found that the planet is only about four times as massive as Jupiter, making it the lightest exoplanet ever detected with the combined use of astrometric measurements and direct imaging .

The AF Leporis system shares similar characteristics with our Solar System. The star is about the same mass, size, and temperature as the Sun, and the planet orbits it at a distance similar to that between Saturn and the Sun.

The system also has a debris belt with characteristics similar to the Kuiper belt. Since the AF Leporis system is only 24 million years old (it is about 200 times younger than the Sun), studying this system can shed light on how our own Solar System formed.