Scientists stunned by exoplanet’s eccentric orbit

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A team of researchers has discovered a distant exoplanet with a wildly eccentric orbit.

A team of researchers led by astronomer Stephen Kane from San Francisco State University has observed an exoplanet with one of the most “eccentric” orbits ever spotted. According to a report from, the planet reflected a signal of starlight from its atmosphere as it approached its host star.

The planet, named HD 20782, is located roughly 117 light-years from Earth. In the context of the study, the word “eccentric” refers to the elliptical path the planet takes around its sun. The planet has the most eccentric orbit of any world ever observed, with a measure of 0.96.

The planet orbits its sun in an almost flattened elliptical pattern, coming extremely close to the star before veering sharply back out into space. The exoplanet offers a unique opportunity for studying the atmosphere on a world with a highly eccentric orbit, one that has thus far eluded astronomers.

The light reflected from HD 20782’s atmosphere offers new insights about its composition and what happens when it comes within such close range of a star. The planet reaches a distance 2.5 times that between the Earth and our own sun at its farthest point, and comes within just six percent of that distance at its closest point.

According to Kane, “It’s around the mass of Jupiter, but it’s swinging around its star like it’s a comet.” Kane and his colleagues believed that the planet had an eccentric orbit before the latest study, but they were surprised by the dramatic elliptical pattern of its path.

The study was part of the Transit Ephemeris Refinement and Monitoring Survey, or TERMS project led by Kane. The project’s goal is to detect exoplanets as they pass in front of their host stars.

“When we see a planet like this that is in an eccentric orbit, it can be really hard to try and explain how it got that way,” said Kane. “It’s kind of like looking at a murder scene, like those people who examine blood spatter patterns on the walls. You know something bad has happened, but you need to figure out what it was that caused that.”

A news release from San Francisco State University describing the details of the study can be found here.

Daniel J. Brown

Daniel J. Brown (Editor-in-Chief) is a recently retired data analyst who gets a kick out of reading and writing the news. He enjoys good music, great food, and sports, with a slant towards Southern college football, basketball and professional baseball.

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