Giant Alien Planet in Supersized Solar System May Solve Mystery

The glowing atmosphere of a strangely giant alien world could help solve mysteries of not just how it formed, but how our own solar system arose, scientists say.

The exoplanet discovery comes from the most detailed look yet at the alien planets around the distant star HR 8799, which lies about 130 light-years from Earth. The HR 8799 system is home to four giant planets orbiting a relatively young, 30-million-year-old star, with each planet far larger than any world found in Earth's solar system.

The planets orbiting HR 8799 weigh in at between five to 10 times the mass of Jupiter and are still glowing with the heat of their formation, allowing researchers to directly image them.

"It's the only system in which multiple planets can individually be seen," said study co-author Bruce Macintosh, an astronomer at Lawrence Livermore National Laboratory in California.

The planetary system resembles a scaled-up version of our solar system, suggesting there may be smaller Earth-size planets closer in, although the researchers currently have not yet seen any.

It even "has something that kind of looks like maybe an asteroid belt interior to the closest giant planet like we have in our solar system, and something that maybe you can refer to as an Oort cloud analog out beyond the most distant gas giant" — that is, a cloud of icy comets, said study lead author Quinn Konopacky, an astronomer at the University of Toronto.

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