Stanford Professor of Physics, Bruce Macintosh and an international collaboration of researchers have recently discovered 51 Eridani b, a Jupiter-like planet and the first exoplanet discovered by a new instrument known as the Gemini Planet Imager (GPI).
The Gemini Planet Imager (GPI) was designed to identify and analyze faint, young planets orbiting bright stars. The primary benefit of GPI technology is direct imaging, where GPI instead searches for light from the planet itself. Once the image of the star is acquired, astronomers use adaptive optics to sharpen the image and block out the light from the star itself. All remaining incoming light is then analyzed, with the brightest spots indicating a possible planet.
51 Eridani b is the newest of the nearly 100 total exoplanets that the research team has discovered using GPI, which was installed on the eight-meter Gemini South Telescope in Chile last year.
According to the researchers, exoplanet 51 Eridani b features the strongest atmospheric methane signal on record. Previous Jupiter-like exoplanets have shown only faint traces of methane, in contrast to the heavy methane atmospheres of the gas giants in our solar system. This feature along with other characteristics, the researchers said, point to a planet that is very similar to what models suggest Jupiter was like in its infancy.
“In the atmospheres of the cold giant planets of our solar system, carbon is found as methane, unlike most exoplanets, where carbon has mostly been found in the form of carbon monoxide,” said Mark Marley in a statement, an astrophysicist at NASA Ames Research Center. “Since the atmosphere of 51 Eri b is also methane rich, it signifies that this planet is well on its way to becoming a cousin of our own familiar Jupiter.”
“51 Eridani b is the first one that’s cold enough and close enough to the star that it could have indeed formed right where it is the ‘old-fashioned way,’” Macintosh said. “This planet really could have formed the same way Jupiter did – the whole solar system could be a lot like ours.”
This newly found exoplanet revolves around the star, 51 Eri, which is one of the youngest and closest stars to the Sun, according to postdoctoral researcher Eric Nielson. 51 Eri was born 20 million years ago, 40 million years after the dinosaurs died out.
Observing younger star systems is considered one of the best ways to learn about how our solar system evolved. The researchers believe that the discovery of this Jupiter-like planet within a young system that could serve as a decoder ring for understanding how planets formed around our sun. Their results suggest that 51 Eridani b is a million times fainter than its parent star and shows the strongest methane signature ever detected on an alien planet, which could yield additional clues as to how the planet formed.
In the future, researchers hope that using GPI to study more young systems such as 51 Eridani b will help them understand the formation of neighbor planets and how common that planet-forming mechanism is throughout the universe.