James Webb Telescope observes Jupiter-like extrasolar planet 51 Eridani b

Artistic conception of the Jupiter-like exoplanet 51 Eridani b that has been targeted by James Webb Telescope for Observation on October 20, 2022. Credits: Danielle Futselaar and Franck Marchis, SETI Institute

October 20, 2022

James Webb Telescope has targeted an exoplanet system 51 Eridani today. 51 Eridani is a star located in the constellation Eridanus. It is only faintly visible to the unaided eye in suburban and rural sky due to its apparent magnitude of 5.22. The absolute magnitude of the main star is 2.87. It is a triple star system because it is joined by the binary star GJ 3305, which has the same proper velocity across space as it. A "Jupiter-like" planet called 51 Eridani b orbits the young star 51 Eridani in the Eridanus constellation. It is about 20 million years old, 96 light years away from our solar system.

Despite being identified in December 2014, 51 Eridani b was only discovered in August 2015 thanks to the Gemini Planet Imager, a global initiative run by the Kavli Institute for Particle Astrophysics and Cosmology. The Gemini Planet Imager's first exoplanet discovery was 51 Eridani b. The Gemini Planet Imager was developed specifically for "direct imaging," which allows it to identify and assess dim, more recent planets around brilliant stars. Astronomers can use adaptive optics to increase the resolution of a target star's image via direct imaging, and then block the star's radiation. The brightest spots in any remaining incoming light are examined next, and they could indicate a planet. Each of the previously discovered directly photographed worlds has previously been a gas giant several times before the finding of 51 Eridani b.

This animation displays an exoplanet the size of Jupiter orbiting 51 Eridani, a Sun-like star, some 11 billion miles away. Because the planetary system is facing Earth, astronomers may observe the planet's motion from a unique vantage point. The Gemini Planet Imager on the Chilean Gemini South Telescope captured five photos over the course of four years for the film. The exoplanet, which is much fainter and smaller, is visible thanks to Gemini's coronagraph, which filters out the majority of the starlight.