http://arxiv.org/abs/1910.07345
Volatile molecules are critical to habitability, yet difficult to observe directly at the optically thick midplanes of protoplanetary disks, where planets form. We present a new technique to measure indirectly the bulk atomic composition and distribution of solids that have been removed from the gas accreting onto the young star TW Hydrae. Our results suggest that disk gaps and planetesimal formation in TW Hya efficiently prevent radial drift and effectively block replenishment of the inner disk solids from ice reservoirs. Volatile-enhancement of giant planet atmospheres cannot be explained by primary accretion of this gas. Half of the missing oxygen is locked in silicates inside the snowline, while carbon is predominantly locked in organics beyond the CO snowline, leaving terrestrial planet-forming region solids both ‘dry’ and carbon-poor. Earth’s depletion of carbon could be common amongst terrestrial exoplanets.
M. McClure and C. Dominik
Thu, 17 Oct 19
52/62
Comments: Main text (~2500 words, 3 figures, 1 table) & supplemental text (~2500 words, 4 figures, 2 tables), under review at a journal