Using color, size, and variability of 700 DES TNOs to constrain birth regions of dynamical classes
Session 10.07 Spectroscopy
Thursday 06-27 | 16:20 - 16:40

For the well-defined sample of 697 trans-Neptunian objects (TNOs) with absolute magnitudes 5.5<Hr<8.2 detected in the Dark Energy Survey, we characterize the relationships between their dynamical class and their physical properties – namely Hr, indicative of size; their colors c={ gr, ri, iz }, indicative of surface composition; and their semi-amplitude A of flux variation, indicative of asphericity and surface inhomogeneity. DES has by far the largest sample to date of TNOs with all these properties measured. If the physical properties are markers of heliocentric distance of formation, then this informs us of the birth region of each present-day dynamical group. We find that the physical properties of the cold classical, hot classical, detached, scattering, and resonant TNOs are all well described by each dynamical class being a different mixture of just 2 common underlying physical populations, which we term “near-IR bright” (NIRB) and “near-IR faint” (NIRF). Some departure from this model of 2 birth populations may be required to explain the color distribution of the detached TNOs. The large sample also allows a more detailed characterization of the inclination distribution of classical TNOs vs their physical properties and putative birth regions.

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