JWST NIR Spectral Observations of the Active Centaurs 450P/LONEOS and C/2014 OG392 (PANSTARRS)
Session 12.04 Spectroscopy
Friday 06-28 | 10:10 - 10:30

Centaurs are small icy bodies residing in orbits between Neptune and Jupiter containing some of the least processed materials in our solar system. A small fraction of known Centaurs (~12%) have been observed to display comet-like comae at times. The types of Centaur comae manifestations displayed range from persistent heliocentric-distance-dependent production rates, to sudden short-lived – hours-to-days long – outbursts, to periods of sustained activity not directly correlated with heliocentric distance. While these different types of comae have been observed for decades through observations of their dust coma, their underlying activity drivers are poorly understood. There are proposed mechanisms, including the sublimation of hypervolatiles or the release of trapped gases during an amorphous water ice (AWI) crystallization phase transition. A major hurdle restricting our ability to identify what is driving activity in an individual Centaur, and subsequently what are the drivers of the active Centaur population as a whole, has been the lack of observing facilities with sensitivities suitable to observe their gas comae. Fortunately, the sensitivity and spectral resolution of JWST NIRSpec provide for the first time the ability to detect simultaneously gas-phase H2O, CO, CO2, and CO+ (and their isotopologues) along with solid-phase ices in the Centaur region. We present new results from JWST NIRSpec IFU Prism mode observations of Centaurs 450P/LONEOS and C/2014 OG392 (PANSTARRS) as part of the Cycle 1 GO Program 2416 (PI A. McKay) that seeks to better understand the diversity of activity drivers in the Centaur region. In our presentation we will discuss a new analysis of gas comae measurements of 450P and C/2014 OG392 provided by their NIRSpec spectra in context with multi-year dust coma activity measurements of each acquired through the Gemini Large and Long Program 203 (PI C. Schambeau).

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