LPL Colloquium: Dr. Megan Schwamb

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New Perspectives Big and Small of the Kuiper Belt 

Thursday, April 7, 2016 3:45pm to 4:45pm
Kuiper Space Sciences: Room 312

Postdoctoral Fellow
Inst. of Astronomy and Astrophysics
National Taiwan University

The small icy bodies beyond Neptune in the Kuiper belt originated in the construction zones that formed our planets. As the fossils left over from the era of planet formation, these bodies inform our knowledge about the growth of planetary embryos and the dynamical evolution of our Solar System. In this talk, I present new efforts to explore and explain the compositional variety within the Kuiper belt. I will describe a proposed framework to reconcile the range of densities found in the Pluto-sized dwarf planets. I will argue that the largest bodies in the Kuiper belt form with densities near that of Pluto's largest moon Charon and that two different collisional pathways produce the emerging dwarf planet dichotomy in ice/rock fractions and satellite-to-primary size ratio. I will also present an overview of the Colours of the Outer Solar System Origins Survey (ColOSSOS), an on-going effort on the  8-m Gemini North telescope to probe surface compositions by obtaining broad-band optical and infrared colors of ~150 Kuiper belt objects (KBOs) with m_r’ <= 23.5 mag (50-300 km in size) discovered from a single well characterized survey. Previous physical property studies in this size range examined the hodgepodge set of KBOs discovered by surveys with different and varying detection biases that make it challenging to test giant planet migration hypotheses and probe the conditions of the early planetesimal disk. ColOSSOS will create an unprecedented dataset combining surface color information, orbital dynamics, and population statistics to probe the history of the Kuiper belt and the late stages of Neptune's migration.