CHEMISTRY IN DISKS. III. PHOTOCHEMISTRY AND X-RAY DRIVEN CHEMISTRY PROBED BY THE ETHYNYL RADICAL (CCH) IN DM Tau, LkCa 15, AND MWC 480

Henning, Th.; Semenov, D.; Guilloteau, S.; Dutrey, Anne; Hersant, F.; Wakelam, Valentine; Chapillon, E.; Launhardt, R.; Piétu, V.; Schreyer, K.

doi:10.1088/0004-637x/714/2/1511

Cited by 94 publications

(132 citation statements)

References 49 publications

(59 reference statements)

Supporting

Mentioning

119

Contrasting

Order By: Relevance

“…(Chapillon et al 2012b;Henning et al 2010). They also suggest the CS molecules are located above one scale height from the disk plane, in reasonable agreement with predictions from chemical models.…”

Section: Discussionsupporting

confidence: 82%

“…The CS(3-2) data set itself suggests low temperatures, but the surface density profile is essentially flat (p = 0.14 ± 0.20), so the constraint may be considered as relatively weak. The temperature found with CS(3-2) is quite compatible with the one determined from CCH (Henning et al 2010) and CN and HCN (Chapillon et al 2012b). Moreover, the CS(5-4) data, although quite noisy, can be used to rule out high temperatures.…”

Section: Simple Modelsupporting

confidence: 85%

“…CO isotopologues and other molecules like HCO + and CN yield typical linewidths around 0.18 km s −1 at 300 AU, but attributing this to thermal or nonthermal motions remains difficult, as their thermal width at 30 K is 0.14 km s −1 (Piétu et al 2007;Chapillon et al 2012b). Moreover, current chemical models fail to explain their vertical location in the molecular layer since CN, CCH or HCN appear to be in a colder molecular layer than predicted (Henning et al 2010;Chapillon et al 2012b).…”

Section: Introductionmentioning

confidence: 85%

See 2 more Smart Citations

Chemistry in disks

Guilloteau

Dutrey

Wakelam

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

Context. Turbulence is thought to be a key driver of the evolution of protoplanetary disks, regulating the mass accretion process, the transport of angular momentum, and the growth of dust particles. Aims. We intend to determine the magnitude of the turbulent motions in the outer parts (>100 AU) of the disk surrounding DM Tau. Methods. Turbulent motions can be constrained by measuring the nonthermal broadening of line emission from heavy molecules. We used the IRAM Plateau de Bure interferometer to study emission from the CS molecule in the disk of DM Tau. High spatial (1.4 × 1. ) and spectral resolution (0.126 km s −1 ) CS J = 3-2 images provide constraints on the molecule distribution and velocity structure of the disk. A low sensitivity CS J = 5-4 image was used in conjunction to evaluate the excitation conditions. We analyzed the data in terms of two parametric disk models, and compared the results with detailed time-dependent chemical simulations.Results. The CS data confirm the relatively low temperature suggested by observations of other simple molecules. The intrinsic linewidth derived from the CS J = 3-2 data is much larger than expected from pure thermal broadening. The magnitude of the derived nonthermal component depends only weakly on assumptions about the location of the CS molecules with respect to the disk plane. Our results indicate turbulence with a Mach number around 0.4-0.5 in the molecular layer. Geometrical constraints suggest that this layer is located near one scale height, in reasonable agreement with chemical model predictions.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Simple Modelsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 85%

See 1 more Smart Citation

Chemistry in disks

Guilloteau

Dutrey

Wakelam

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…We used the C 2 H 3 → 2 line to derive the upper limit to the C 2 H abundance. Recent results by Henning et al (2010) show that the excitation temperature of C 2 H could be lower than 10 K in some disks. Then, the value of the upper limit would increase.…”

Section: Averaged Molecular Abundances In the Diskmentioning

confidence: 99%

Molecular content of the circumstellar disk in AB Aurigae

Fuente

Cernicharo

Agúndez

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. Very few molecular species have been detected in circumstellar disks surrounding young stellar objects. We are carrying out an observational study of the chemistry of circumstellar disks surrounding T Tauri and Herbig Ae stars. First results of this study are presented in this note. Methods. We used the EMIR receivers recently installed at the IRAM 30 m telescope to carry out a sensitive search for molecular lines in the disks surrounding AB Aur, DM Tau, and LkCa 15. Results. We detected lines of the molecules HCO + , CN, H 2 CO, SO, CS, and HCN toward AB Aur. In addition, we tentatively detected DCO + and H 2 S lines. The line profiles suggest that the CN, HCN, H 2 CO, CS, and SO lines arise in the disk. This makes it the first detection of SO in a circumstellar disk. We have unsuccessfully searched for SO toward DM Tau and LkCa 15, and for c-C 3 H 2 toward AB Aur, DM Tau, and LkCa 15. Our upper limits show that contrary to all molecular species observed so far, SO is not as abundant in DM Tau as it is in AB Aur.Conclusions. Our results demonstrate that the disk associated with AB Aur is rich in molecular species. Our chemical model shows that the detection of SO is consistent with that expected from a very young disk where the molecular adsorption onto grains does not yet dominate the chemistry.

show abstract

“…Far-infrared (Far-IR) spectroscopic observations of young premain-sequence stars have the potential to reveal the gas and dust composition of protoplanetary disks in regions not probed at any other wavelengths (e.g., van Dishoeck 2004;Lorenzetti 2005;Henning et al 2010). The atomic and molecular transitions in the far-IR regime (50−200 μm) span a large range in upper energy level (from a few 10 K to a few 10 3 K) and are sensitive to the warm (a few 10 2 K) upper layers of the disk (n < 10 8 cm −3 ).…”

Section: Introductionmentioning

confidence: 99%

DIGIT survey of far-infrared lines from protoplanetary disks

Fedele

Bruderer

Dishoeck

et al. 2013

A&A

Self Cite

114

146

View full text Add to dashboard Cite

We present far-infrared (50−200 μm) spectroscopic observations of young pre-main-sequence stars taken with Herschel/PACS as part of the DIGIT key project. The sample includes 16 Herbig AeBe and 4 T Tauri sources observed in SED mode covering the entire spectral range. An additional 6 Herbig AeBe and 4 T Tauri systems have been observed in SED mode with a limited spectral coverage. Multiple atomic fine structure and molecular lines are detected at the source position:The most common feature is the [O i] 63 μm line detected in almost all of the sources, followed by OH. In contrast with CO, OH is detected toward both Herbig AeBe groups (flared and non-flared sources). An isothermal LTE slab model fit to the OH lines indicates column densities of 10 13 < N OH < 10 16 cm −2 , emitting radii 15 < r < 100 AU and excitation temperatures 100 < T ex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ≥ 10 10 cm −3 ) are needed to reproduce the observations. The OH emission thus comes from a warm layer in the disk at intermediate stellar distances. Warm H 2 O emission is detected through multiple lines toward the T Tauri systems AS 205, DG Tau, S CrA and RNO 90 and three Herbig AeBe systems HD 104237, HD 142527, HD 163296 (through line stacking). Overall, Herbig AeBe sources have higher OH/H 2 O abundance ratios across the disk than do T Tauri disks, from near-to far-infrared wavelengths. Far-infrared CH + emission is detected toward HD 100546 and HD 97048. The slab model suggests moderate excitation (T ex ∼ 100 K) and compact (r ∼ 60 AU) emission in the case of HD 100546.Off-source [O i] emission is detected toward DG Tau, whose origin is likely the outflow associated with this source. The [C ii] emission is spatially extended in all sources where the line is detected. This suggests that not all [C ii] emission is associated with the disk and that there is a substantial contribution from diffuse material around the young stars. The flux ratios of the atomic fine structure linesare analyzed with PDR models and require high gas density (n 10 5 cm −3 ) and high UV fluxes (G o ∼ 10 3 −10 7 ), consistent with a disk origin for the oxygen lines for most of the sources.

show abstract

CHEMISTRY IN DISKS. III. PHOTOCHEMISTRY AND X-RAY DRIVEN CHEMISTRY PROBED BY THE ETHYNYL RADICAL (CCH) IN DM Tau, LkCa 15, AND MWC 480

Cited by 94 publications

References 49 publications

Chemistry in disks

Chemistry in disks

Molecular content of the circumstellar disk in AB Aurigae

DIGIT survey of far-infrared lines from protoplanetary disks

Contact Info

Product

Resources

About