PERTH: Astronomers say they’ve spotted a remarkably close analogue to our own planet Jupiter — and even gotten a look at its methane-rich atmosphere.
Maybe our solar system isn’t such an oddball after all. As planet-hunting telescopes have scanned the starry heavens, they’ve discovered all kinds of strange worlds that are unlike those in our own solar neighborhood: hot Jupiters, super-Earths, mini-Neptunes. But now, astronomers say they’ve spotted a remarkably close analogue to our own planet Jupiter — and even gotten a look at its methane-rich atmosphere.
The planet, 51 Eridani b, was the first to be found using the Gemini Planet Imager. The discovery, described in the journal Science, could give researchers deeper insight into the makeup of such exoplanets — as well as a potential glimpse into the evolution of our own solar system.
“It really, as far as we can tell, is pretty much like what Jupiter looked like at that age,” study leader Bruce Macintosh, an astronomer at Stanford University, said of the young planet. “And by studying the light from it … we can hope to understand the process that made it form.”
The gas giant’s star, 51 Eridani, sits about 100 light-years away in the constellation Eridanus (nearby Orion). The planet is thought to hold roughly twice the mass of our own one-eyed Jupiter and lies a little farther out, past where Saturn would sit.
Its atmosphere holds water vapor and gives off the strongest methane signature yet detected on an exoplanet. (Jupiter also features methane and water vapor in its atmosphere.)
Astronomers have discovered many other gas giant planets — particularly with NASA’s Kepler spacecraft, which has turned up more than 1,000 confirmed exoplanets of all types and sizes — but those behemoths tend to be very close to their host star. That’s very different from the planets around our home star, where the small, rocky ones stay close to the sun and the large, gassy ones fill up far more distant orbits.
