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THE EVOLUTION OF INNER DISK GAS IN TRANSITION DISKS
journal contribution
posted on 2016-02-09, 14:35 authored by K. Hoadley, K. France, Richard D. Alexander, M. McJunkin, P. C. SchneiderInvestigating the molecular gas in the inner regions of protoplanetary disks (PPDs) provides insight into how the molecular disk environment changes during the transition from primordial to debris disk systems. We conduct a small survey of molecular hydrogen (H[Subscript: 2]) fluorescent emission, using 14 well-studied Classical T Tauri stars at two distinct dust disk evolutionary stages, to explore how the structure of the inner molecular disk changes as the optically thick warm dust dissipates. We simulate the observed Hi-Lyman α-pumped H[Subscript: 2] disk fluorescence by creating a 2D radiative transfer model that describes the radial distributions of H[Subscript: 2] emission in the disk atmosphere and compare these to observations from the Hubble Space Telescope. We find the radial distributions that best describe the observed H[Subscript: 2] FUV emission arising in primordial disk targets (full dust disk) are demonstrably different than those of transition disks (little-to-no warm dust observed). For each best-fit model, we estimate inner and outer disk emission boundaries (r[Subscript: in] and r[Subscript: out]), describing where the bulk of the observed H[Subscript: 2] emission arises in each disk, and we examine correlations between these and several observational disk evolution indicators, such as n[Subscript: 13–31], r[Subscript: in, CO], and the mass accretion rate. We find strong, positive correlations between the H[Subscript: 2] radial distributions and the slope of the dust spectral energy distribution, implying the behavior of the molecular disk atmosphere changes as the inner dust clears in evolving PPDs. Overall, we find that H[Subscript: 2] inner radii are ~4 times larger in transition systems, while the bulk of the H[Subscript: 2] emission originates inside the dust gap radius for all transitional sources.
History
Citation
Astrophysical Journal, 2015, 812 (1), 41Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and AstronomyVersion
- VoR (Version of Record)
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Astrophysical JournalPublisher
IOP Publishing LTDissn
0004-637Xeissn
1538-4357Acceptance date
2015-09-03Copyright date
2015Available date
2016-02-09Publisher DOI
Publisher version
http://iopscience.iop.org/article/10.1088/0004-637X/812/1/41/metaLanguage
enAdministrator link
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Keywords
Science & TechnologyPhysical SciencesAstronomy & Astrophysicscircumstellar matterISM: moleculesline: profilesprotoplanetary disksstars: pre-main sequenceultraviolet: starsT-TAURI STARSMOLECULAR-HYDROGEN EMISSIONMAIN-SEQUENCE STARSYOUNG CIRCUMSTELLAR DISKSPLANET-FORMING ZONESPROTOPLANETARY DISKSFAR-ULTRAVIOLETV4046 SGRORGANIC-MOLECULESH-2 FLUORESCENCE