For the first time, astronomers have discovered a pair of extrasolar planets with highly eccentric orbits that are locked in a two-to-one orbital resonance – a relationship where one planet orbits its star twice for every one orbit completed by the other.

Two exoplanets, HD 41248 b and c, orbit a young G-type (Sun-like) star located approximately 177 light-years (1,665 trillion km) away in the constellation of Auriga.

"The eccentricity value gives information about how elliptical an orbit is. If the value is zero, we deal with a perfect circle; but an orbit is called highly eccentric if its value reaches above ~0.9. In this sense, both discovered Jupiter-like planets have very pronounced elliptical orbits around their host star,'' says Dr Man Ho Chan from CfA/Harvard & Smithsonian. “Such extreme eccentricity, in addition to other intriguing features of HD 41248 b and c, provide an exciting opportunity to better understand various properties of Jupiter-like planets that formed or migrated very close to their central stars during the early formation of planetary systems.“

One explanation to such pronounced and aligned ellipticities could be a Kozai migration in a stellar binary system with an additional eccentric orbit, Dr Ji Wang from CfA continues,'' which could imply an ongoing dynamical interaction within the surrounding environment of these two exoplanets.''

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