Exo-Doppelganger: Jupiter's Twin Seen Orbiting Sun's Twin

You don’t get to meet your double every day, but Jupiter and the sun share the same galaxy as their very own doppelgängers.

HIP 11915 is a sun-like star that not only looks like our sun, it is also the same mass and even the same age. But most remarkably, astronomers have discovered a world in orbit around that star that not only resembles gas giant Jupiter, it has a similar mass and also occupies a strikingly similar orbit.

This discovery has some fascinating implications for planetary formation and the possibility of truly Earth-like planets forming elsewhere in our galaxy.

Jupiter is well known to be the gravitational powerhouse of our solar system. The solar system was once a violent and tumultuous place, but the gravitational heft of Jupiter stabilized the inner solar system, making it a conducive environment to form Earth in a stable orbit inside our sun’s habitable zone.

Current theories also suggest that Jupiter had a huge part to play in “vacuuming” the inner solar system, clearing many errant asteroids and comets from slamming into a fledgling Earth. This had the effect of allowing life to gain a foothold on our planet, throttling the number of extinction-level impacts.

So, spotting another Jupiter in orbit around another sun-like star has striking implications for furthering our quest to find another planetary oasis and gives us an idea about how common planetary systems like ours may be.

“The quest for an Earth 2.0, and for a complete Solar System 2.0, is one of the most exciting endeavors in astronomy,” said Jorge Melendez, of the Universidade de São Paulo, Brazil, leader of the study and co-author of a paper to appear in the journal Astronomy and Astrophysics.

The astronomers used the powerful HARPS instrument that is mounted on th European Southern Observatory’s 3.6-meter telescope at the La Silla Observatory in Chile to spot the orbiting Jupiter-like world. HARPS uses the radial velocity method to tease out the slight wobble caused by the gravitational tugging of exoplanets on their parent stars. By deriving the frequency of the wobbles, astronomers can accurately calculate a planet’s mass, it’s orbital distance and period.

Read more at Discovery News