English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present self-consistent models of gas in optically-thick dusty disks andcalculate its thermal, density and chemical structure. The models focus on anaccurate treatment of the upper layers where line emission originates, and atradii $\gtrsim 0.7$ AU. We present results of disks around $\sim 1{\rmM}_{\odot}$ stars where we have varied dust properties, X-ray luminosities andUV luminosities. We separately treat gas and dust thermal balance, andcalculate line luminosities at infrared and sub-millimeter wavelengths from alltransitions originating in the predominantly neutral gas that lies below theionized surface of the disk. We find that the [ArII] 7$\mu$m, [NeII]12.8$\mu$m, [FeI] 24$\mu$m, [SI] 25$\mu$m, [FeII] 26$\mu$m, [SiII] 35 $\mu$m,[OI] 63$\mu$m and pure rotational lines of H$_2$, H$_2$O and CO can be quitestrong and are good indicators of the presence and distribution of gas indisks. We apply our models to the disk around the nearby young star, TW Hya,and find good agreement between our model calculations and observations. Wealso predict strong emission lines from the TW Hya disk that are likely to bedetected by future facilities. A comparison of CO observations with our modelssuggests that the gas disk around TW Hya may be truncated to $\sim 120 $ AU,compared to its dust disk of 174 AU. We speculate that photoevaporation due tothe strong stellar FUV field from TW Hya is responsible for the gas disktruncation.

Line Emission from Gas in Optically Thick Dust Disks around Young Stars