Jupiter’s twin found orbiting Sun-like star

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As the hunt for exoplanets continues, astronomers using the European Southern Observatory’s 3.6-metre telescope have stumbled upon a planet-star system which almost resemble Jupiter-Sun pair.

The discovery was made by a Brazilian-led team, which has been researching Sun-like stars in a bid to find planetary systems similar to our Solar System. The team found Jupiter’s twin orbiting at the same distance from a Sun-like star, HIP 11915, at exactly the same distance as Jupiter.

The discovery of the new exoplanet has been attributed to 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.

Researchers say that although other teams have found planets similar to Jupiter orbiting other stars in the galaxy, the newly discovered planet is the most accurate analogue yet found for the Sun and Jupiter – both in terms of mass and distance from its host star, and in terms of the similarity between the host star and our Sun.

The planet’s host, the solar twin HIP 11915, is not only similar inmass 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.

According to Jorge Melendez, of the Universidade de São Paulo, Brazil, the leader of the team and co-author of the paper, “the quest for an Earth 2.0, and for a complete Solar System 2.0, is one of the most exciting endeavors in astronomy. We are thrilled to be part of this cutting-edge research, made possible by the observational facilities provided by ESO.”

Megan Bedell, from the University of Chicago and lead author of the paper, concludes: “After two decades of hunting for exoplanets, we are finally beginning to see long-period gas giant planets similar to those in our own Solar System thanks to the long-term stability of planet hunting instruments like HARPS. This discovery is, in every respect, an exciting sign that other solar systems may be out there waiting to be discovered.”

Follow-up observations are needed to confirm and constrain the finding, but HIP 11915 is one of the most promising candidates so far to host a planetary system similar to our own.