2012 Annual Science Report
Arizona State University Reporting | SEP 2011 – AUG 2012
Astrophysical Controls on the Elements of Life, Task 4: Model the Injection of Supernova Material Into Protoplanetary Disks
The goal of this project is to determine whether supernova material could be injected into a protoplanetary disk, the disk of gas and dust from which planets form. A secondary issue is whether these materials would be mixed within the disk efficiently, and whether such an injection into our own protoplanetary disk can explain the isotopic evidence from meteorites that the solar system contained short-lived radionuclides like 26Al.
In the last year we have continued to model aspects of disk physics and radial transport. These are pertinent to the question of how radionuclides injected by the supernova into a protoplanetary disk might subsequently be mixed. Our modeling of the last year has not focused on the injection itself.
In the area of disk physics and radial transport we cite 1 refereed paper and 1 conference abstract. The radiative transfer code described in the refereed paper by Lesniak & Desch (2011) is novel and may be better than other codes at calculating disk midplane temperatures in very optically thick disks. For various reasons, we predict temperatures somewhat colder than those calculated by others. The conference abstract by Desch on snow lines in photoevaporated disks suggests that stars forming in a massive star forming region will likely be photoevaporated by the ultraviolet radiation from a nearby massive star, driving an outward flow of gas in the disk that ultimately carries water out of the inner solar nebula, possibly explaining the large depletion of water in the Earth (relative to solar abundances). We are pursuing this research more thoroughly because of its implications for mixing in disks.