Alien-planet imager discovers the most Jupiter-like world ever found

The new-found planet circles the star 51 Eridani, located about 100 light years away – a short hop by galactic standards.

That 20 million-year-old star is quite young, and that’s what made detecting the planet possible.

Travis Barman, a planetary scientist at the University of Arizona who took part in the study published in the journal Science, said: “51 Eri b is the first young planet that probably looks like Jupiter did billions of years ago, making it… our most important corner-piece of the planet-formation jigsaw puzzle”.

The planet, 51 Eridani b, was discovered by the new Gemini Planet Imager (GIP), an instrument that is operated by global astronomers. Kepler indirectly finds planets by detecting a loss of starlight as a world passes in front of its star.

“Of all the directly imaged planets so far, this is the first one where we’ve gotten a spectrum that shows methane”, Bruce Macintosh, the head of the GPI team, a professor of physics at Stanford University and a member of the Kavli Institute for Particle Astrophysics and Cosmology, said to redOrbit via email.

The image you see above has been created in a very rudimentary way to demonstrate the size of the planet 51 Eri b within our own solar system. It is classified as a young Jupiter, is a million times less bright than its central star, and has a rather unique atmosphere, the study explains.

In addition to being the faintest planet ever imaged, it’s also the coldest-800 degrees Fahrenheit, whereas others are around 1,200 degrees-and features the strongest atmospheric methane signal on record.

“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”, study co-author Mark Marley, an astrophysicist at NASA Ames Research Center, said in a statement. These signatures are believed to show a picture of what our own Jupiter looked like in its infancy.

Despite the sophistication, direct imaging remains so hard that astronomers will be able to see only large exoplanets-Jupiter-sized or bigger-that are young, still hot, and glowing with infrared light.

“This planet really could have formed the same way Jupiter did – this whole planetary system could be a lot like ours”.

To confirm the planet, the GPI can then analyze its chemical fingerprint. She then helped confirm the planet’s presence by measuring how far it is away from its host star.

Of the almost 2000 exoplanets discovered to date, only about 10 have been seen directly, because they are so faint compared with the bright stars they orbit.

This planet is around 96 light-years from Earth, and is the smallest exoplanet ever to be seen by a telescope here on Earth.

Marois said 51 Eridani b is the first planet discovered with this technique that appears to have been formed the same way as planets in our own solar system – from tiny dust particles clumping together into rocks and eventually the core of a planet. Other directly-imaged planets are five times the mass of Jupiter or more. The cold-start scenario, called core accretion, can also form rocky planets like Earth and Mars, but the hot-start model of gravitational collapse might only make giant gas planets.

The researchers suggest that 51 Eri b, as a sort of young Jupiter, might be forming much like giant planets did in the solar system, as opposed to the manner in which researchers suspect radically different worlds such ashot Jupiters formed elsewhere in the universe. The planet is so young and still has a temperature of 400 °C, which is hot enough to melt lead.

The researchers said they plan to begin observing 51 Eri b again in late September, when it emerges from behind the sun, in order to map out the exoplanet’s orbit.