• First detection of molecular oxygen at a #comet
    http://blogs.esa.int/rosetta/2015/10/28/first-detection-of-molecular-oxygen-at-a-comet

    ESA’s #Rosetta spacecraft has made the first in situ detection of oxygen molecules outgassing from a comet, a surprising observation that suggests they were incorporated into the comet during its formation. This news story is mirrored from the main ESA web portal. #rosetta has been studying #Comet_67P/Churyumov–Gerasimenko for over a year and has detected an abundance of different gases pouring from its nucleus. #water vapour, carbon monoxide and carbon dioxide are the most prolific, with a rich array of other nitrogen-, sulphur- and carbon-bearing species, and even ‘noble gases’ also recorded. Oxygen is the third most abundant element in the Universe, but the simplest molecular version of the gas, O2, has proven surprisingly hard to track down, even in star-forming clouds, because it is highly (...)

    #Comets #Instruments #Science #coma #instruments #science

    • We weren’t really expecting to detect O2 at the comet – and in such high abundance – because it is so chemically reactive, so it was quite a surprise,” says Kathrin Altwegg of the University of Bern, and principal investigator of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis instrument, ROSINA.

      It’s also unanticipated because there aren’t very many examples of the detection of interstellar O2. And thus, even though it must have been incorporated into the comet during its formation, this is not so easily explained by current Solar System formation models.