It’s rare that we get to see exoplanets themselves. Most often, planets in other star systems are too small and too dim to be directly detected, so astronomers infer their presence based on their effects on their host stars. But occasionally, it is possible to image a star directly — and recently, astronomers managed to create not only an image, but a video of an exoplanet orbiting its star.
The time-lapse video shows a planet called Beta Pictoris b, located 63 light-years away in the constellation Pictor. The planet is big and its star is bright, which, along with its relatively close proximity, allowed researchers to see it directly. The time-lapse covers 17 years of footage in just 10 seconds, showing the planet moving around three quarters of the way around one orbit.
“We need another six years of data before we can see one whole orbit,” said lead researcher Jason Wang of Northwestern University in a statement. “We’re almost there. Patience is key.”
The planet was first imaged in 2003, making it among the first generation of exoplanets discovered. It has a mass around 13 times that of Jupiter, and is about 50% larger in size than Jupiter is. Along with its young, bright host star, that enabled astronomers to detect it early on.
“It’s extremely bright,” Wang said. “That’s why it’s one of the first exoplanets to ever be discovered and directly imaged. It’s so big that it’s at the boundary of a planet and a brown dwarf, which are more massive than planets.”
Data was collected using the Gemini Observatory’s Gemini Planet Imager and the European Southern Observatory’s NACO and SPHERE instruments. To turn the 17 years of observations into a video, the researchers used computer algorithms to process the images via a technique called motion interpolation, which turns a series of static images into smooth motion. Further processing was required to remove the blurring effects of Earth’s atmosphere and to reduce the glare from the bright star.
The result is a video showing the longest time-lapse footage of an exoplanet to date.
“A lot of times, in science, we use abstract ideas or mathematical equations,” Wang said. “But something like a movie — that you can see with your own eyes — gives a visceral kind of appreciation for physics that you wouldn’t gain from just looking at plots on a graph.”
