A Surface Density Perturbation in the TW Hydrae Disk at 95 au Traced by Molecular Emission

Teague, Richard; Semenov, D.; Gorti, Uma; Guilloteau, S.; Henning, Th.; Birnstiel, T.; Dutrey, Anne; Boekel, R. van; Chapillon, E.

doi:10.3847/1538-4357/835/2/228

Cited by 43 publications

(56 citation statements)

References 62 publications

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“…the 'Doppler flip'; Casassus & Perez 2019). This morphology better matches the observations in the context of an embedded planet at a radius of ∼ 90 au (Teague et al 2017;Mentiplay et al 2019). We note, however, that the simulations of Dong et al (2019) show that there can be significant v z components significantly offset in the azimuthal direction from the embedded planet.…”

Section: An Embedded Planetsupporting

confidence: 84%

“…The spirals of warm gas bound a shadow observed in scattered NIR light (van Boekel et al 2017), consistent with the hypothesis that this is a region that is shadowed and thus receives less incident photons to heat the gas. The spiral in velocity overlaps the significant gap in the gas surface density at 90 au (van Boekel et al 2017;Teague et al 2017), with perturbations of 10% of the local Keplerian rotation if they are believed to be changes in the rotation speed. Equivalently, vertical motions on the order of 1% of the rotation speed are also consistent.…”

Section: Discussionmentioning

confidence: 83%

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Spiral Structure in the Gas Disk of TW Hya

Teague

Bae

Huang

et al. 2019

ApJL

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100

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We report the detection of spiral substructure in both the gas velocity and temperature structure of the disk around TW Hya, suggestive of planet-disk interactions with an unseen planet. Perturbations from Keplerian rotation tracing out a spiral pattern are observed in the SE of the disk, while significant azimuthal perturbations in the gas temperature are seen in the outer disk, outside 90 au, extending the full azimuth of the disk. The deviation in velocity is either ∆v φ / v kep ∼ 0.1 or ∆v z / v kep ∼ 0.01 depending on whether the perturbation is in the rotational or vertical direction, while radial perturbations can be ruled out. Deviations in the gas temperature are ±4 K about the azimuthally averaged profile, equivalent to deviations of ∆T gas / T gas ∼ 0.05. Assuming all three structures can be described by an Archimedean spiral, measurements of the pitch angles of both velocity and temperature spirals show a radially decreasing trend for all three, ranging from 9 • at 70 au, dropping to 3 • at 200 au. Such low pitch-angled spirals are not readily explained through the wake of an embedded planet in the location of previously reported at 94 au, but rather require a launching mechanism which results in much more tightly wound spirals. Molecular emission tracing distinct heights in the disk is required to accurately distinguish between spiral launching mechanisms.

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Section: An Embedded Planetsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 83%

Spiral Structure in the Gas Disk of TW Hya

Teague

Bae

Huang

et al. 2019

ApJL

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100

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“…A series of studies of the disk associated with TW Hydrae -the closest T Tauri star -has significantly improved our understanding of disk physics and chemistry. This disk is seen almost face-on, maximizing its surface, and the dust and gas distributions have been intensively observed and modeled (Qi et al 2004;Andrews et al 2012;Rosenfeld et al 2012;Qi et al 2013;Andrews et al 2016;van Boekel et al 2016;Teague et al 2017). The J=1-0 transition of HD, the hydrogen deuteride, has been also detected by Bergin et al (2013) who determined the gas mass of the disk to be > 0.056 M , a value ranging at the upper end of previous estimates based on indirect mass tracers ( 5·10 -0.06 M , (Thi et al 2010;Gorti et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The Flying Saucer: Tomography of the thermal and density gas structure of an edge-on protoplanetary disk

Dutrey

Guilloteau

Piétu

et al. 2017

A&A

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Context. Determining the gas density and temperature structures of protoplanetary disks is a fundamental task to constrain planet formation theories. This is a challenging procedure and most determinations are based on model-dependent assumptions. Aims. We attempt a direct determination of the radial and vertical temperature structure of the Flying Saucer disk, thanks to its favorable inclination of 90 degrees. Methods. We present a method based on the tomographic study of an edge-on disk. Using ALMA, we observe at 0.5 resolution the Flying Saucer in CO J=2-1 and CS J=5-4. This edge-on disk appears in silhouette against the CO J=2-1 emission from background molecular clouds in ρ Oph. The combination of velocity gradients due to the Keplerian rotation of the disk and intensity variations in the CO background as a function of velocity provide a direct measure of the gas temperature as a function of radius and height above the disk mid-plane. Results. The overall thermal structure is consistent with model predictions, with a cold (< 15 − 12 K), CO-depleted mid-plane, and a warmer disk atmosphere. However, we find evidence for CO gas along the mid-plane beyond a radius of about 200 au, coincident with a change of grain properties. Such a behavior is expected in case of efficient rise of UV penetration re-heating the disk and thus allowing CO thermal desorption or favoring direct CO photo-desorption. CO is also detected up to 3-4 scale heights while CS is confined around 1 scale height above the mid-plane. The limits of the method due to finite spatial and spectral resolutions are also discussed. Conclusions. This method appears to be very promising to determine the gas structure of planet-forming disks, provided that the molecular data have an angular resolution which is high enough, of the order of 0.3 − 0.1 at the distance of the nearest star forming regions.

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“…Debes et al 2013;Akiyama et al 2015;Rapson et al 2015;van Boekel et al 2017), and molecular line emission (e.g. Nomura et al 2016;Schwarz et al 2016;Teague et al 2017). The origins of these features and their relationships to one another are not yet definitively established.…”

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confidence: 99%

CO and Dust Properties in the TW Hya Disk from High-resolution ALMA Observations

Huang

Andrews

Cleeves

et al. 2018

ApJ

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We analyze high angular resolution ALMA observations of the TW Hya disk to place constraints on the CO and dust properties. We present new, sensitive observations of the 12 CO J = 3 − 2 line at a spatial resolution of 8 AU (0. 14). The CO emission exhibits a bright inner core, a shoulder at r ≈ 70 AU, and a prominent break in slope at r ≈ 90 AU. Radiative transfer modeling is used to demonstrate that the emission morphology can be reasonably reproduced with a 12 CO column density profile featuring a steep decrease at r ≈ 15 AU and a secondary bump peaking at r ≈ 70 AU. Similar features have been identified in observations of rarer CO isotopologues, which trace heights closer to the midplane. Substructure in the underlying gas distribution or radially varying CO depletion that affects much of the disk's vertical extent may explain the shared emission features of the main CO isotopologues. We also combine archival 1.3 mm and 870 µm continuum observations to produce a spectral index map at a spatial resolution of 2 AU. The spectral index rises sharply at the continuum emission gaps at radii of 25, 41, and 47 AU. This behavior suggests that the grains within the gaps are no larger than a few millimeters. Outside the continuum gaps, the low spectral index values of α ≈ 2 indicate either that grains up to centimeter size are present, or that the bright continuum rings are marginally optically thick at millimeter wavelengths.

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A Surface Density Perturbation in the TW Hydrae Disk at 95 au Traced by Molecular Emission

Cited by 43 publications

References 62 publications

Spiral Structure in the Gas Disk of TW Hya

Spiral Structure in the Gas Disk of TW Hya

The Flying Saucer: Tomography of the thermal and density gas structure of an edge-on protoplanetary disk

CO and Dust Properties in the TW Hya Disk from High-resolution ALMA Observations

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