hr8799
HR 8799 has a mass about 1.5 times that of our own Sun, and lies about 130 light years from the Sun -- a distance similar to many stars easily visible in the night sky. Pictured above, a 10-meter Keck telescope in Hawaii captured in infrared light three planets orbiting an artificially obscured central star. C. Marois et al./NRC Canada

Less than 130 light-years from Earth — a mere stone’s throw away as things are measured in the cosmic scale — lies a young star named HR 8799. Although perhaps unremarkable in an objective sense, for us humans, this is a special celestial object. It, and its system of planets, is one of the first to be directly imaged by astronomers.

Usually, the presence of exoplanets — planets that orbit a star other than our sun — is confirmed through indirect means, such as by studying the dimming of the parent star’s light when an object passes in front of it. In 2008, however, scientists were able to, for the first time, observe three of HR 8799’s four planets directly using the Keck and Gemini telescopes in Hawaii.

Now, eight years hence, Jason Wang — an astronomy student at the University of California, Berkeley — has used images taken by the Keck observatory to create a short but stunning video showing the four exoplanets in motion.

The creation of the video, which is just three-seconds long, required images gathered over a period of seven years. Even then, it shows only a tiny portion of the planets’ full orbits — which range in duration from 40 Earth years for the nearest one to over 400 years for the farthest one.

via GIPHY

“The data was obtained over 7 years from one of the 10 meter Keck telescopes by a team of astronomers (Christian Marois, Quinn Konopacky, Bruce Macintosh, Travis Barman, and Ben Zuckerman),” Wang told Universe Today in an email. “Christian reduced each of the 7 epochs of data, to make 7 frames of data. I then made a movie by using a motion interpolation to interpolate those 7 frames into 100 frames to get a smooth video so that it's not choppy (as if we could observe them every month from Earth).”

All the planets in the 40-million-year-old system are heavier than Jupiter, and can be seen as bright floating orbs in the video. The black circle in the centre is the result of an effort to block out the star’s light — thereby making the planets visible.

Directly imaging exoplanets is extremely hard, especially because of the technical difficulties involved in blocking out the light from the parent stars. Of the over 3,400 confirmed exoplanets, only a handful has ever been directly observed.

Despite this, however, astronomers continue to strive to image exoplanets, as they believe doing so could provide vital clues to the formation and evolution of planets — something that is still scarcely understood.

“It's just hard to go back billions and billions of years and rewind time in our own solar system,” Wang told National Geographic. “We rather find it easier to study young star systems like this to understand planet formation.”

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