Munich, Nov 22 : A team of French astronomers has used the European Southern Observatory's (ESO's) Very Large Telescope (VLT) to detect a planet-like object located very close to the star Beta Pictoris, and which apparently lies inside its disc.
With a projected distance from the star of only 8 times the Earth-Sun distance, this object is most likely the giant planet suspected from the peculiar shape of the disc and the previously observed infall of comets onto the star.
It would then be the first image of a planet that is as close to its host star as Saturn is to the Sun.
The hot star Beta Pictoris is one of the best-known examples of stars surrounded by a dusty 'debris' disc.
Debris discs are composed of dust resulting from collisions among larger bodies like planetary embryos or asteroids.
Earlier observations showed a warp of the disc, a secondary inclined disc and infalling comets onto the star.
"These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star," said team leader Anne-Marie Lagrange.
In 2003, the French team used the NAOS-CONICA instrument, mounted on one of the 8.2 m Unit Telescopes of ESO's VLT, to study the immediate surroundings of Beta Pictoris.
Recently, a member of the team re-analysed the data in a different way to seek the trace of a companion to the star. Infrared wavelengths are indeed very well suited for such searches.
"For this, the real challenge is to identify and subtract as accurately as possible the bright stellar halo," explained Lagrange. "We were able to achieve this after a precise and drastic selection of the best images recorded during our observations," she added.
The strategy proved very rewarding, as the astronomers were able to discern a feeble, point-like glow well inside the star's halo.
To eliminate the possibility that this was an artifact and not a real object, a battery of tests was conducted and several members of the team, using three different methods, did the analysis independently, always with the same success.
Moreover, the companion was also discovered in other data sets, further strengthening the team's conclusion that the companion is real.
"Our observations point to the presence of a giant planet, about 8 times as massive as Jupiter and with a projected distance from its star of about 8 times the Earth-Sun distance, which is about the distance of Saturn in our Solar System," said Lagrange.