The European Southern Observatory (ESO) announced on Wednesday that its Very Large Telescope (VLT) had taken the first ever image of a young Sun-like star with two giant exoplanets orbiting it. The star is designated TYC 8998-760-1 and lies some 300 light years away. The planets have been designated TYC 8998-760-1b and TYC 8998-760-1c. The discovery has been published in The Astrophysical Journal Letters.
“Even though astronomers have indirectly detected thousands of planets in our galaxy, only a tiny fraction of these exoplanets have been directly imaged,” pointed out Leiden University (in the Netherlands) Associate Professor and study co-author Matthew Kenworthy. “[D]irect observations are important in the search for environments that can support life.”
This is only the third time that two or more exoplanets orbiting the same star have been directly observed and imaged. But in the previous two cases, the stars concerned were very different to our Sun.
“Our team has now been able to take the first image of two gas giant companions that are orbiting a young, solar analogue,” highlighted Leuven Catholic University (Belgium) study team member and postdoctoral researcher Maddalena Reggiani. “This discovery is a snapshot of an environment that is very similar to our Solar System, but at a much earlier stage of its evolution,” noted research leader and Leiden University PhD student Alexander Bohn.
TYC 8998-760-1 lies in the Southern Hemisphere constellation Musca (the Fly) and is only some 17-million years old. It was described by Bohn as being a “very young version of our Sun”. Its two orbiting gas giant planets are, however, far out from it. While the Solar System’s two biggest planets, Jupiter and Saturn, are respectively five and ten astronomical units (AUs) from the Sun, TYC 8998-760-1’s two gas giants are 160 and 320 AUs from it. (An AU is the average distance between the Sun and the Earth.)
The two exoplanets are also much more massive than our Solar System’s gas giants. The inner one has a mass 14 times that of Jupiter, while the outer one is six times more massive than Jupiter.
The VLT was also the instrument that captured the first ever image of an exoplanet, in 2004. The ESO is an intergovernmental organisation created in 1962 by 16 European countries and Chile, the last-named hosting the observatory. The ESO is currently building the Extremely Large Telescope (ELT) which will have a 39 m main mirror and be the largest optical and near-infrared telescope in the world.
“The possibility that future instruments, such as those available on the ELT, will be able to detect even lower-mass planets around this star marks an important milestone in understanding multi-planet systems, with potential implications for the history of our own Solar System,” observed Bohn. Other questions yet to be answered include: did these two gas giants form in their current orbits, or did they migrate into them from elsewhere?