Jupiter twin discovered orbiting Sun-like star

 Astronomers have discovered a Jupiter-like exoplanet orbiting a Sun-like star, bringing scientists closer to finding a Solar System 2.0 - planetary system that mirrors our own.

An international group of astronomers used the European Southern Observatory (ESO)'s 3.6-metre telescope to identify the planet just like Jupiter orbiting at the same distance from a Sun-like star, HIP 11915.

According to current theories, the formation of Jupiter-mass planets plays an important role in shaping the architecture of planetary systems.

The existence of a Jupiter-mass planet in a Jupiter-like orbit around a Sun-like star opens the possibility that the system of planets around this star may be similar to our own Solar System, researchers said.

HIP 11915 is about the same age as the Sun and, furthermore, its Sun-like composition suggests that there may also be rocky planets orbiting closer to the star.

So far, exoplanet surveys have been most sensitive to planetary systems that are populated in their inner regions by massive planets, down to a few times the mass of Earth.

This contrasts with our Solar System, where there are small rocky planets in the inner regions and gas giants like Jupiter farther out.

According to the most recent theories, the arrangement of our Solar System, so conducive to life, was made possible by the presence of Jupiter and the gravitational influence this gas giant exerted on the Solar System during its formative years.

It would seem, therefore, that finding a Jupiter twin is an important milestone on the road to finding a planetary system that mirrors our own, researchers said.

The new discovery was made using HARPS, one of the world's most precise planet-hunting instruments, mounted on the ESO 3.6-metre telescope at the La Silla Observatory in Chile.

Although many planets similar to Jupiter have been found at a variety of distances from Sun-like stars, this newly discovered planet, in terms of both mass and distance from its host star, and in terms of the similarity between the host star and our Sun, is the most accurate analogue yet found for the Sun and Jupiter.

The planet's host, the solar twin HIP 11915, is not only similar in mass to the Sun, but is also about the same age. To further strengthen the similarities, the composition of the star is similar to the Sun's.

The chemical signature of our Sun may be partly marked by the presence of rocky planets in the Solar System, hinting at the possibility of rocky planets also around HIP 11915.

"The quest for an Earth 2.0, and for a complete Solar System 2.0, is one of the most exciting endeavours in astronomy," said Jorge Melendez, from Universidade de Sao Paulo, Brazil, who led the team.

"This discovery is, in every respect, an exciting sign that other solar systems may be out there waiting to be discovered," said Megan Bedell, from the University of Chicago.