Direct Observations of a Planet Orbiting a Star 63 Light-Years Away

By Matthew Williams November 13, 2018
Direct Observations of a Planet Orbiting a Star 63 Light-Years Away

Given its size and wide orbit, Beta Pictoris b was an excellent candidate for direct imaging, which the SPHERE instrument was specifically designed for. In most cases, extra-solar planets are impossible to directly image using current telescopes because the light from their stars obscures any light reflected from their surfaces and atmospheres. This is especially the case with smaller rocky planets that orbit closer to their stars.

The light reflected off of Beta Pictoris b's atmosphere is what enabled SPHERE to discover and track its orbit, and to spot it as it emerged from its passage in front of its parent star. It is important to note that this did not constitute a transit, as the planet does not pass directly in front of its star relative to Earth-bound observers. For this reason, the planet has not detected using the Transit Method.

At 9 AU from its star (1.3 billion km; 800 million mi), Beta Pictoris b orbits its star at distance that is similar to Saturn's orbits of our Sun. This makes it the most closely orbiting exoplanet to ever be directly imaged. The images captured by the ESO team also allowed for a time-lapse video that shows the planet circling its star between 2014 and 2018 (shown below).

Both the discovery of Beta Pictoris b and the more recent way it was tracked were remarkable achievements. They are also characteristic of the transition that is currently taking place in exoplanet studies. With thousands of planets confirmed and available for study, scientists are moving away from the process of discovery and towards exoplanet characterization (determining the composition of their atmospheres and if they could actually support life).

In the coming years, many more exoplanets are expected to be discovered using the direct imaging method, thanks to next-generation telescopes that will have greater resolution and sensitivity. These include the James Webb Space Telescope (JWST), the Extremely Large Telescope (ELT) and the Giant Magellan Telescope (MGT).

And be sure to check out the time-lapse video of Peta Pictoris b, courtesy of the ESO:

Matthew Williams

Matthew Williams

Matt Williams is a space journalist, science communicator, and author with several published titles and studies. His work is featured in The Ross 248 Project and Interstellar Travel edited by NASA alumni Les Johnson and Ken Roy. He also hosts the podcast series Stories from Space at ITSP Magazine. He lives in beautiful British Columbia with his wife and family. For more information, check out his website.