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AR 13881 (Archival Research)

Sat Jul 20 09:16:16 GMT 2024

Principal Investigator: Nuria Calvet
PI Institution: University of Michigan
Investigators (xml)

Title: The formation of Lyman alpha fluorescent H2 lines in protoplanetary disks surrounding young solar mass stars
Cycle: 22

Abstract
We propose to carry out a theoretical study of the formation of the H2 UV lines created by Lyman alpha fluorescence in protoplanetary disks around solar mass stars. We will use irradiated accretion disks models in which the dust and gas temperatures, as well as the hydrostatic density structure and corresponding chemistry is solved self-consistently, using as input realistic high energy fields, and observed ranges of accretion luminosities. We will include gas opacities in addition to dust to calculate the transfer of high energy radiation, which will enable us to model the gas disk inside the dust destruction radius where a substantial contribution to the flux of the H2 lines arises. The models will also include effects of dust settling by varying the vertical and radial distribution of the dust, which will have a direct effect on the the penetration of high energy radiation with implications for the gas temperature structure, the chemistry, and the strength of the H2 fluorescent lines. We will create a dedicated website with predicted H2 fluorescent line luminosities for a set of models covering ranges of stellar and accretion parameters typical of accreting solar mass stars and different degrees of dust settling. Our study will support efforts of the Ultraviolet Initiative of Cycle 22 by providing the community with the best means to interpret the FUV COS and STIS H2 spectra of young accreting stars.