Journal article
UV Fluorescence Traces Gas and Ly alpha Evolution in Protoplanetary Disks
The Astronomical journal, Vol.162(5), p.185
11/01/2021
DOI: 10.3847/1538-3881/ac1593
Abstract
Ultraviolet spectra of protoplanetary disks trace distributions of warm gas at radii where rocky planets form. We combine Hubble Space Telescope Cosmic Origins Spectrograph observations of H-2 and CO emission from 12 classical T Tauri stars to more extensively map inner disk surface layers, where gas temperature distributions allow radially stratified fluorescence from the two species. We calculate empirical emitting radii for each species under the assumption that the line widths are entirely set by Keplerian broadening, demonstrating that the CO fluorescence originates further from the stars r similar to 0.8au <i . This is supported by 2D radiative transfer models, which show that the peak and outer radii of the CO flux distributions generally extend further into the outer disk than the H-2. These results also indicate that additional sources of Ly alpha photons remain unaccounted for, requiring more complex models to fully reproduce the molecular gas emission. As a first step, we confirm that the morphologies of the UV-CO bands and Ly alpha radiation fields are significantly correlated and discover that both trace the degree of dust disk evolution. The UV tracers appear to follow the same sequence of disk evolution as forbidden line emission from jets and winds, as the observed Ly alpha profiles transition between dominant red wing and dominant blue wing shapes when the high-velocity optical emission disappears. Our results suggest a scenario where UV radiation fields, disk winds and jets, and molecular gas evolve in harmony with the dust disks throughout their lifetimes.
Details
- Title: Subtitle
- UV Fluorescence Traces Gas and Ly alpha Evolution in Protoplanetary Disks
- Creators
- Nicole Arulanantham - Space Telescope Science InstituteKevin France - Laboratory for Atmospheric and Space PhysicsKeri Hoadley - University of IowaP. C. Schneider - Hamburger Fern-HochschuleCatherine C. Espaillat - Boston UniversityH. M. Guenther - MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USAGregory J. Herczeg - Kavli Institute for Theoretical SciencesAlexander Brown - Laboratory for Atmospheric and Space Physics
- Resource Type
- Journal article
- Publication Details
- The Astronomical journal, Vol.162(5), p.185
- Publisher
- IOP Publishing Ltd
- DOI
- 10.3847/1538-3881/ac1593
- ISSN
- 0004-6256
- eISSN
- 1538-3881
- Number of pages
- 23
- Grant note
- David & Ellen Lee Prize Postdoctoral Fellowship in Experimental Physics at Caltech 80NSSC17K0531 / NASA Earth and Space Science Fellowship GO-15070; HST-GO-15128.001A / HST ACI-1532235; ACI-1532236 / National Science Foundation; National Science Foundation (NSF) Colorado State University University of Colorado Boulder
- Language
- English
- Date published
- 11/01/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984429031502771
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