Probing the Inner Oort Cloud / Dr Meg Schwamb (Institute of Astronomy & Astrophysics, Academia Sinica)

Abstract
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The discovery of Sedna, nearly a decade ago, on a highly eccentric orbit beyond the Kuiper belt challenged our understanding of the Solar System. With a perihelion of 76 AU, Sedna is well beyond the reach of the gas-giants and could not be scattered onto its highly eccentric orbit from interactions with Neptune alone. Sednaˇ¦s aphelion at ~1000 AU is too far from the edge of the Solar System to feel the perturbing effects of passing stars or galactic tides in the present-day solar neighborhood. Some other mechanism no longer active in the Solar System today is required to emplace Sedna on its orbit. Sedna's origin remains an outstanding question in planetary astronomy.

Sedna's presence predicts a population of icy bodies on similar orbits residing past the Kuiper belt detached from the Solar System in what has been called the Inner Oort Cloud. The recent discovery of 2012 VP113 confirms the presence of the Inner Oort Cloud. The orbits of these distant planetoids are dynamically frozen in place providing a fossilized record of their formation. Finding just a handful of these bodies, we can begin to read this dynamical record. I will present the results of a wide-field survey aimed to to find the largest and brightest members of this population. In particular, I will focus on the constraints that can be placed on the proposed formation scenario where stellar encounters, early on in an embedded cluster phase of the Solar System, created Sedna-like orbits. I will also present new dynamical modeling to probe the location of the inner edge of the Inner Oort cloud and its implications for future observational campaigns searching for new members of this population.