The GRAVITY instrument on the European Southern Observatory’s Very Large Telescope Interferometer (VLTI) has made the first direct observation of an exoplanet using optical interferometry. The result was presented last month in the paper, “First Direct Detection of an Exoplanet by Optical Interferometry,” published in the scientific journalAstronomy and Astrophysics.One ofthe study’s co-authors is 51 Pegasi b Fellow Jason Wang, who is currently pursuing his post-doctoral research at the California Institute of Technology in Pasadena, California.

Dr. Wang emphasizes that, “Long-baseline interferometry allows us to combine 8-meter telescopes, some of the largest telescopes in the world currently, to achieve the resolution of a 100-meter telescope, which is far bigger than the 30- to 40-meter telescopes that are planned in the next decade. Using GRAVITY, we can directly measure the position of exoplanets more than ten times better than any other instrument in the world.”

With this technique, the first observations were made on the massive exoplanet HR8799, often characterized as a “super Jupiter.” The approach revealed that HR8799 has a complex atmosphere with high levels of carbon monoxide and clouds of iron and silicate dust. This composition suggests that the atmosphere is in a constant state of dramatic and violent storms. Because HR8799 is in a relatively young system (30-50 million years old), it presents key opportunities for scientists to advance our understanding of planet and planetary system formation.

This is the first time that optical interferometry has been used to directly characterize an exoplanet, and it demonstrates the potential of this technique. Dr. Wang adds, “The benefits of this technique are amazing. We will be able to trace out the orbits of these exoplanets so finely that we hope to measure the gravitational tugs of planets on one another, just like how Neptune was predicted to exist based on the irregularities in Uranus’s orbit. In the far future, if we can use this technique on telescopes separated by 10 kilometers, we could even map out the surfaces of nearby exoplanets.”

Read the European Southern Observatory’s full announcement.