Dear Gemini: Thanks for Col-OSSOS

Tuesday, 18 April 2023 8 a.m. — 9 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
Wesley Fraser (Herzberg Astronomy and Astrophysics Research Centre)


Col-OSSOS, or Colours of the Outer Solar System Origins Survey, was one of the first LLP programs to execute on Gemini-North. Starting in 2014B, and finally completing observations of a few straggler targets in 2022B, Col-OSSOS used GMOS and NIRI, and Megacam on the CFHT to gather near simultaneous UV-optical-NIR colours of > 100 Kuiper Belt Objects. The design of Col-OSSOS was built around the recognition of a correlated compositional-dynamical structure of the current Kuiper Belt, and took full advantage of the unique fast camera switching capabilities offered by the Gemini telescopes. The main goals of Col-OSSOS were to quantify the compositional structure of the Kuiper Belt, and to map that structure in a way that can provide additional constraint on the formative history of the early Solar System. To that end, Col-OSSOS has been quite successful, having demonstrated a shockingly simple compositional taxonomy that possesses only two classes. Col-OSSOS has also revealed critical easy-to-identify anomalous objects that clearly exhibit unique dynamical-thermal histories, the origins of which still remain unexplained, and squashed some critical misconceptions about the interpretation of the colour-distribution of Kuiper Belt Objects. In this talk, I will attempt to summarize the numerous results of Col-OSSOS, including numerous in-prep or in-press results. In the final section of this presentation, I will highlight some new results from observations of Kuiper Belt Objects by the James Webb Space Telescope. In particular, I will present some results of the large spectral program (PI: Pinilla-Alonso) which includes the discovery of CO, which is unstable at Kuiper Belt surface temperatures, and tie those results together with the Col-OSSOS program, which is providing the context for these critical (but expensive!) spectral observations.