scholarly journals Gas Cavities inside Dust Cavities in Disks Inferred from ALMA Observations

2015 ◽  
Vol 10 (S314) ◽  
pp. 139-142
Author(s):  
Nienke van der Marel ◽  
Ewine F. van Dishoeck ◽  
Simon Bruderer ◽  
Paola Pinilla ◽  
Tim van Kempen ◽  
...  
Keyword(s):  
Protoplanetary Disks ◽  
Gas Emission ◽  
Chemical Modeling ◽  
Gas Density ◽  
Spatially Resolved ◽  
Outer Disk ◽  
Physical Chemical ◽  
Planetary Mass ◽  
Dust Distribution ◽  
Modeling Code

AbstractProtoplanetary disks with cavities in their dust distribution, also named transitional disks, are expected to be in the middle of active evolution and possibly planet formation. In recent years, millimeter-dust rings observed by ALMA have been suggested to have their origin in dust traps, caused by pressure bumps. One of the ways to generate these is by the presence of planets, which lower the gas density along their orbit and create pressure bumps at the edge. We present spatially resolved ALMA Cycle 0 and Cycle 1 observations of CO and CO isotopologues of several famous transitional disks. Gas is found to be present inside the dust cavities, but at a reduced level compared with the gas surface density profile of the outer disk. The dust and gas emission are quantified using the physical-chemical modeling code DALI. In the majority of these disks we find clear evidence for a drop in gas density of at least a factor of 10 inside the cavity, whereas the dust density drops by at least a factor 1000. The CO isotopologue observations reveal that the gas cavities are significantly smaller than the dust cavities. These gas structures suggest clearing by one or more planetary-mass companions.

scholarly journals Organic molecules in the protoplanetary disk of DG Tauri revealed by ALMA

2019 ◽  
Vol 623 ◽  
pp. L6 ◽  
Author(s):  
L. Podio ◽  
F. Bacciotti ◽  
D. Fedele ◽  
C. Favre ◽  
C. Codella ◽  
...  
Keyword(s):  
Column Density ◽  
Protoplanetary Disks ◽  
Temperature Inversion ◽  
Abundance Ratio ◽  
Chemical Compositions ◽  
Outer Disk ◽  
T Tauri ◽  
Dust Distribution ◽  
Disk Height ◽  
Co Emission

Context. Planets form in protoplanetary disks and inherit their chemical compositions. Aims. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks. Methods. We analyze ALMA observations of the nearby disk-jet system around the T Tauri star DG Tau in the o − H2CO 31, 2 − 21, 1 and CH3OH 3−2, 2 − 4−1, 4 E, 50, 5 − 40, 4 A transitions at an unprecedented resolution of $ {\sim}0{{\overset{\prime\prime}{.}}}{15} $, i.e., ∼18 au at a distance of 121 pc. Results. The H2CO emission originates from a rotating ring extending from ∼40 au with a peak at ∼62 au, i.e., at the edge of the 1.3 mm dust continuum. CH3OH emission is not detected down to an rms of 3 mJy beam−1 in the 0.162 km s−1 channel. Assuming an ortho-to-para ratio of 1.8−2.8 the ring- and disk-height-averaged H2CO column density is ∼0.3−4 × 1014 cm−2, while that of CH3OH is < 0.04−0.7 × 1014 cm−2. In the inner 40 au no o − H2CO emission is detected with an upper limit on its beam-averaged column density of ∼0.5−6 × 1013 cm−2. Conclusions. The H2CO ring in the disk of DG Tau is located beyond the CO iceline (RCO ∼ 30 au). This suggests that the H2CO abundance is enhanced in the outer disk due to formation on grain surfaces by the hydrogenation of CO ice. The emission peak at the edge of the mm dust continuum may be due to enhanced desorption of H2CO in the gas phase caused by increased UV penetration and/or temperature inversion. The CH3OH/H2CO abundance ratio is < 1, in agreement with disk chemistry models. The inner edge of the H2CO ring coincides with the radius where the polarization of the dust continuum changes orientation, hinting at a tight link between the H2CO chemistry and the dust properties in the outer disk and at the possible presence of substructures in the dust distribution.

scholarly journals Shadowing and multiple rings in the protoplanetary disk of HD 139614

2020 ◽  
Vol 635 ◽  
pp. A121 ◽  
Author(s):  
G. A. Muro-Arena ◽  
M. Benisty ◽  
C. Ginski ◽  
C. Dominik ◽  
S. Facchini ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Scattered Light ◽  
Protoplanetary Disks ◽  
Position Angle ◽  
Protoplanetary Disk ◽  
Disk Model ◽  
Outer Disk ◽  
Planetary Mass ◽  
Azimuthal Asymmetries ◽  
Multiple Rings

Context. Shadows in scattered light images of protoplanetary disks are a common feature and support the presence of warps or misalignments between disk regions. These warps are possibly caused by an inclined (sub-)stellar companion embedded in the disk. Aims. We aim to study the morphology of the protoplanetary disk around the Herbig Ae star HD 139614 based on the first scattered light observations of this disk, which we model with the radiative transfer code MCMax3D. Methods. We obtained J- and H-band observations that show strong azimuthal asymmetries in polarized scattered light with VLT/SPHERE. In the outer disk, beyond ~30 au, a broad shadow spans a range of ~240 deg in position angle, in the east. A bright ring at ~16 au also shows an azimuthally asymmetric brightness, with the faintest side roughly coincidental with the brightest region of the outer disk. Additionally, two arcs are detected at ~34 and ~50 au. We created a simple four-zone approximation to a warped disk model of HD 139614 in order to qualitatively reproduce these features. The location and misalignment of the disk components were constrained from the shape and location of the shadows they cast. Results. We find that the shadow on the outer disk covers a range of position angles too wide to be explained by a single inner misaligned component. Our model requires a minimum of two separate misaligned zones – or a continuously warped region – to cast this broad shadow on the outer disk. A small misalignment of ~4° between adjacent components can reproduce most of the observed shadow features. Conclusions. Multiple misaligned disk zones, potentially mimicking a warp, can explain the observed broad shadows in the HD 139614 disk. A planetary mass companion in the disk, located on an inclined orbit, could be responsible for such a feature and for the dust-depleted gap responsible for a dip in the SED.

scholarly journals Planet formation in action: resolved gas and dust images of a transitional disk and its cavity

2013 ◽  
Vol 8 (S299) ◽  
pp. 90-93
Author(s):  
Nienke van der Marel ◽  
Ewine F. van Dishoeck ◽  
Simon Bruderer ◽  
Til Birnstiel ◽  
Paola Pinilla ◽  
...  
Keyword(s):  
Planet Formation ◽  
Early Stage ◽  
Continuum Emission ◽  
Dust Trapping ◽  
Spatially Resolved ◽  
First Results ◽  
Disk Evolution ◽  
Gas Cavity ◽  
Dust Distribution ◽  
The Continuum

AbstractPlanet formation and clearing of protoplanetary disks is one of the long standing problems in disk evolution theory. The best test of clearing scenarios is observing systems that are most likely to be actively forming planets: the transitional disks with large inner dust cavities. We present the first results of our ALMA (Atacama Large Millimeter/submillimeter Array) Cycle 0 program using Band 9, imaging the Herbig Ae star Oph IRS 48 in CO 6−5 and the submillimeter continuum in the extended configuration. The resulting ~0.2″ spatial resolution completely resolves the cavity of this disk in the gas and the dust. The gas cavity of IRS 48 is half as large as the dust cavity, ruling out grain growth and photoevaporation as the primary cause of the truncation. On the other hand, the continuum emission reveals an unexpected large azimuthal asymmetry and steep edges in the dust distribution along the ring, suggestive of dust trapping. We will discuss the implications of the combined gas and dust distribution for planet formation at a very early stage. This is one of the first transition disks with spatially resolved gas inside the cavity, demonstrating the superb capabilities of the Band 9 receivers.

scholarly journals Herbig Ae/Be Star Disks at High Angular Resolution

2004 ◽  
Vol 221 ◽  
pp. 389-394
Author(s):  
C. P. Dullemond ◽  
C. Dominik ◽  
R. van Boekel ◽  
R. Waters ◽  
M. van den Ancker
Keyword(s):  
Angular Resolution ◽  
Protoplanetary Disks ◽  
Spectral Energy ◽  
High Angular Resolution ◽  
Be Stars ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Spatially Resolved ◽  
Be Star ◽  
Geometric Picture

We show that there exists a simple geometric picture for the geometries of protoplanetary disks around Herbig Ae/Be stars that explains the two main kinds of spectral energy distributions found for these objects, and that makes predictions that are qualitatively in agreement with currently available spatially resolved images and/or interferometric measurements. Also it qualitatively explains the phenomenon of UX Orionis variability.

scholarly journals Chemical modeling of FU Ori protoplanetary disks

2018 ◽  
Vol 14 (S345) ◽  
pp. 367-368
Author(s):  
Tamara Molyarova ◽  
Vitaly Akimkin ◽  
Dmitry Semenov ◽  
Péter Ábrahám ◽  
Thomas Henning ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Protoplanetary Disks ◽  
Protoplanetary Disk ◽  
Chemical Processes ◽  
Molecular Composition ◽  
Chemical Modeling ◽  
Fu Ori

AbstractLuminosity outbursts of the FU Ori type stars, which have a magnitude of ∼ 100 L⊙ and last for decades, may affect chemical composition of the surrounding protoplanetary disk. Using astrochemical modelling we analyse the changes induced by the outburst and search for species sensitive to the luminosity rise. Some changes in the disk molecular composition appear not only during the outburst itself but can also retain for decades after the end of the outburst. We analyse main chemical processes responsible for these effects and assess timescales at which chemically inert species return to the pre-outburst abundances.

Monitoring and physical-chemical modeling of conditions of natural surface and underground waters forming in the Kola North

2012 ◽  
Vol 47 (5) ◽  
pp. 657-668 ◽  
Author(s):  
Svetlana I. Mazukhina ◽  
Vladimir A. Masloboev ◽  
Konstantin V. Chudnenko ◽  
Valeriy A. Bychinsky ◽  
Anton V. Svetlov ◽  
...  
Keyword(s):  
Chemical Modeling ◽  
Underground Waters ◽  
Physical Chemical ◽  
Natural Surface

scholarly journals Wide Dust Gaps in Protoplanetary Disks Induced by Eccentric Planets: A Mass-eccentricity Degeneracy

2021 ◽  
Vol 922 (2) ◽  
pp. 184
Author(s):  
Yi-Xian Chen ◽  
Zhuoxiao Wang ◽  
Ya-Ping Li ◽  
Clément Baruteau ◽  
Douglas N. C. Lin
Keyword(s):  
Mass Distribution ◽  
Protoplanetary Disks ◽  
Mass Function ◽  
Low Viscosity ◽  
Mass Eccentricity ◽  
Tidal Perturbation ◽  
Ring Structures ◽  
Dust Distribution ◽  
Gas Accretion ◽  
Gap Width

Abstract The tidal perturbation of embedded protoplanets on their natal disks has been widely attributed to be the cause of gap-ring structures in submillimeter images of protoplanetary disks around T Tauri stars. Numerical simulations of this process have been used to propose scaling of characteristic dust-gap width/gap-ring distance with respect to planet mass. Applying such scaling to analyze observed gap samples yields a continuous mass distribution for a rich population of hypothetical planets in the range of several Earth to Jupiter masses. In contrast, the conventional core-accretion scenario of planet formation predicts a bimodal mass function due to (1) the onset of runaway gas accretion above ∼20 Earth masses and (2) suppression of accretion induced by gap opening. Here, we examine the dust disk response to the tidal perturbation of eccentric planets as a possible resolution of this paradox. Based on simulated gas and dust distributions, we show the gap-ring separation of Neptune-mass planets with small eccentricities might become comparable to that induced by Saturn-mass planets on circular orbits. This degeneracy may obliterate the discrepancy between the theoretical bimodal mass distribution and the observed continuous gap width distribution. Despite damping due to planet–disk interaction, modest eccentricity may be sustained either in the outer regions of relatively thick disks or through resonant excitation among multiple super Earths. Moreover, the ring-like dust distribution induced by planets with small eccentricities is axisymmetric even in low viscosity environments, consistent with the paucity of vortices in Atacama Large Millimeter/submillimeter Array images.

scholarly journals Computer and physical-chemical modeling of the evolution of a fractal corrosion front

2021 ◽  
Vol 13 (1) ◽  
pp. 105-124
Author(s):  
Alexandr Anatolevich Shibkov ◽  
Sergey Sergeevich Kochegarov
Keyword(s):  
Chemical Modeling ◽  
Physical Chemical

scholarly journals Rapid CO gas dispersal from NO Lup’s class III circumstellar disc

2020 ◽  
Author(s):  
J B Lovell ◽  
G M Kennedy ◽  
S Marino ◽  
M C Wyatt ◽  
M Ansdell ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Spectral Type ◽  
Circumstellar Dust ◽  
Class Iii ◽  
Gas Emission ◽  
Central Mass ◽  
Spatially Resolved ◽  
Break Up ◽  
Co Emission ◽  
Co Gas

Abstract We observed the K7 class III star NO Lup in an ALMA survey of the 1-3 Myr Lupus association and detected circumstellar dust and CO gas. Here we show that the J = 3-2 CO emission is both spectrally and spatially resolved, with a broad velocity width ∼19 km s−1 for its resolved size ∼1″ (∼130 au). We model the gas emission as a Keplerian disc, finding consistency, but only with a central mass of ∼11M⊙, which is implausible given its spectral type and X-Shooter spectrum. A good fit to the data can also be found by modelling the CO emission as outflowing gas with a radial velocity ∼22 km s−1. We interpret NO Lup’s CO emission as the first imaged class III circumstellar disc with outflowing gas. We conclude that the CO is continually replenished, but cannot say if this is from the break-up of icy planetesimals or from the last remnants of the protoplanetary disc. We suggest further work to explore the origin of this CO, and its higher than expected velocity in comparison to photoevaporative models.

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