Tracing Slow Winds From T Tauri Stars via Low-Velocity Forbidden Line Emission

Simón, M.; Pascucci, Ilaria; Edwards, Suzan; Feng, Wanda; Gorti, Uma; Hollenbach, D. J.; Rigliaco, E.; Keane, J. T.

doi:10.3847/0004-637x/831/2/169

Cited by 147 publications

(333 citation statements)

References 71 publications

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“…Disk photoevaporation by X-ray and UV photons potentially provides an inside-out dispersal mechanism, although this is proposed to be efficient only beyond the radius where the gas is gravitationally bound to the star (1-2 au in disks around solar-mass stars). Another removal mechanism could be through portions of MHD winds (e.g., Ferreira et al 2006;Bai 2016) that may be probed at optical wavelengths through a low-velocity component in the forbidden oxygen lines (Simon et al 2016). A slow disk wind has been proposed to contribute also to the CO narrow component in double-component disks (Bast et al 2011;Pontoppidan et al 2011a), and may play a role in the depletion of molecular gas in inner disks.…”

Section: Origin Of Molecular Holes/gaps In Inner Disksmentioning

confidence: 99%

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

Banzatti

Pontoppidan

Salyk

et al. 2017

ApJ

121

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We present a new velocity-resolved survey of 2.9 μm spectra of hot H 2 O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ∼ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9-33 μm that probe from the dust sublimation radius at ∼0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H 2 O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (Rco), which probes molecular gaps in inner disks. We find that H 2 O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as R co increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars ofgenerally have inner gaps with depleted molecular gas content. We measure radial trends in H 2 O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05-20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA.

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Section: Origin Of Molecular Holes/gaps In Inner Disksmentioning

confidence: 99%

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

Banzatti

Pontoppidan

Salyk

et al. 2017

ApJ

121

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“…Highresolution spectra of GI Tau include broad and narrow components (e.g., Simon et al 2016). The bulk of this emission must originate above the star, where the outflow would not be occulted by an inner disk warp.…”

Section: The Extinction Curve Of the Dips Of Gi Taumentioning

confidence: 99%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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The variability of young stellar objects is mostly driven by star-disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths of DṼ 2.5 mag that last for days to months and often appear to occur stochastically. In 2014-2015, extinctions that repeated with a quasi-period of 21 days over several months are the first empirical evidence of slow warps predicted by magnetohydrodynamic simulations to form at a few stellar radii away from the central star. The reddening is consistent with =  R 3.85 0.5 V and, along with an absence of diffuse interstellar bands, indicates that some dust processing has occurred in the disk. The 2015-2016 multiband light curve includes variations in spot coverage, extinction, and accretion, each of which results in different traces in color-magnitude diagrams. This light curve is initially dominated by a month-long extinction event and a return to the unocculted brightness. The subsequent light curve then features spot modulation with a 7.03 day period, punctuated by brief, randomly spaced extinction events. The accretion rate measured from U-band photometry ranges from´-1.3 10 8 to´-1.1 10 10 M e yr −1 (excluding the highest and lowest 5% of high-and low-accretion rate outliers), with an average of4.7 -10 9 M e yr −1 . A total of 50% of the mass is accreted during bursts of >´-12.8 10 9 M e yr -1, which indicates limitations on analyses of disk evolution using single-epoch accretion rates.

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“…Another possibility is that the weaker CO emission from TOs reflects a smaller emitting area for the gaseous inner disk as whole, not just the radial extent of the region where CO is abundant. In the Simon et al (2016) and CO line profiles may suggest that both the atomic and molecular gas are similarly restricted to larger radii than in CTTS disks, as in a truncated gaseous disk. Because TOs have significant stellar accretion rates, gas from the disk clearly reaches the star.…”

Section: Co Emission and M -Band Excess From Transition Objectsmentioning

confidence: 99%

Residual Gas and Dust around Transition Objects and Weak T Tauri Stars*

Doppmann

Najita

Carr

2017

ApJ

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Residual gas in disks around young stars can spin down stars, circularize the orbits of terrestrial planets, and whisk away the dusty debris that is expected to serve as a signpost of terrestrial planet formation. We have carried out a sensitive search for residual gas and dust in the terrestrial planet region surrounding young stars ranging in age from a few Myr to ∼ 10 Myr in age. Using high resolution 4.7µm spectra of transition objects and weak T Tauri stars, we searched for weak continuum excesses and CO fundamental emission, after making a careful correction for the stellar contribution to the observed spectrum. We find that the CO emission from transition objects is weaker and located further from the star than CO emission from non-transition T Tauri stars with similar stellar accretion rates. The difference is possibly the result of chemical and/or dynamical effects (i.e., a low CO abundance or close-in low-mass planets). The weak T Tauri stars show no CO fundamental emission down to low flux levels (5 × 10 −20 − 10 −18 W m −2 ). We illustrate how our results can be used to constrain the residual disk gas content in these systems and discuss their potential implications for star and planet formation.

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Tracing Slow Winds From T Tauri Stars via Low-Velocity Forbidden Line Emission

Cited by 147 publications

References 71 publications

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Residual Gas and Dust around Transition Objects and Weak T Tauri Stars*

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