A scaled-up solar system

A team of astrophysicists have made the most detailed examination yet of the atmosphere of a Jupiter-like planet beyond our solar system. High-resolution imaging spectrograpy with the Keck ii 10-metre telescope in Hawaii was used to uncover chemical fingerprints of molecules in the planet’s atmosphere. “We have been able to observe this planet in unprecedented detail because of the advanced instrumentation, our ground-breaking observing and data-processing techniques and because of the nature of planetary system,” said Quin Konopacky of the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto. The spectrograph, called OSIRIS revealed a cloudy atmosphere containing carbon monoxide and water vapour. “With this level of detail we can compare the amount of carbon to the amount of oxygen present in the planet’s atmosphere, and this chemical mix provides clues as to how the entire planetary system formed,” said Travis Barman, a Lowell Observatory astronomer and co-author of the paper published in Science. The spectrum suggests that the carbon to oxygen ratio is consistent with the core accretion scenario - the model thought to explain the formation of our Solar System. In the model, plants start off as small rock-ice cores that get larger as they acquire additional mass through gravity. The planet named HR 8799c is one of the four gas giants known to orbit a star 130 light-years away. HR 8799c orbits 40 times farther from its parent star than the Earth orbits from the sun. The core accretion model predicts that the star HR 8799 was once surrounded by nothing but a huge disk of gas and dust. As the gas cooled, ice formed, depleting the disk of oxygen atoms. Large ice and dust clouds attracted surrounding gas to form larger atmospheres. The gas was depleted of oxygen, which is reflected in the planet’s atmosphere. “Our results suggest that HR 8799 is like a scaled-up Solar System. And so, in addition to the gas giants far from their parent star, it would not come as a surprise to find Earth-like planets closer in,” said Konopacky.