The Disk Substructures at High Angular Resolution Project (DSHARP). X. Multiple Rings, a Misaligned Inner Disk, and a Bright Arc in the Disk around the T Tauri star HD 143006

Context. Transition disks are considered sites of ongoing planet formation, and their dust and gas distributions could be signposts of embedded planets. The transition disk around the T Tauri star RY Lup has an inner dust cavity and displays a strong silicate emission feature. Aims. Using high-resolution imaging we study the disk geometry, including non-axisymmetric features, and its surface dust grain, to gain a better understanding of the disk evolutionary process. Moreover, we search for companion candidates, possibly connected to the disk. Methods. We obtained high-contrast and high angular resolution data in the near-infrared with the VLT/SPHERE extreme adaptive optics instrument whose goal is to study the planet formation by detecting and characterizing these planets and their formation environments through direct imaging. We performed polarimetric imaging of the RY Lup disk with IRDIS (at 1.6 μm), and obtained intensity images with the IRDIS dual-band imaging camera simultaneously with the IFS spectro-imager (0.9–1.3 μm). Results. We resolved for the first time the scattered light from the nearly edge-on circumstellar disk around RY Lup, at projected separations in the 100 au range. The shape of the disk and its sharp features are clearly detectable at wavelengths ranging from 0.9 to 1.6 μm. We show that the observed morphology can be interpreted as spiral arms in the disk. This interpretation is supported by in-depth numerical simulations. We also demonstrate that these features can be produced by one planet interacting with the disk. We also detect several point sources which are classified as probable background objects.

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Annular substructures in the transition disks around LkCa 15 and J1610

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038027 ◽

2020 ◽

Vol 639 ◽

pp. A121 ◽

Cited By ~ 3

Author(s):

S. Facchini ◽

M. Benisty ◽

J. Bae ◽

R. Loomis ◽

L. Perez ◽

...

Keyword(s):

Angular Resolution ◽

Outer Edge ◽

Continuum Emission ◽

High Angular Resolution ◽

Broad Ring ◽

T Tauri ◽

Extended Component ◽

Hydrodynamical Simulations ◽

The Continuum ◽

Transition Disks

We present high-resolution millimeter continuum ALMA observations of the disks around the T Tauri stars LkCa 15 and 2MASS J16100501-2132318 (hereafter, J1610). These transition disks host dust-depleted inner regions, which have possibly been carved by massive planets, and they are of prime interest to the study of the imprints of planet-disk interactions. While at moderate angular resolution, they appear as a broad ring surrounding a cavity, the continuum emission resolves into multiple rings at a resolution of ~60 × 40 mas (~7.5 au for LkCa 15, ~6 au for J1610) and ~7 μJy beam−1 rms at 1.3 mm. In addition to a broad extended component, LkCa 15 and J1610 host three and two narrow rings, respectively, with two bright rings in LkCa 15 being radially resolved. LkCa 15 possibly hosts another faint ring close to the outer edge of the mm emission. The rings look marginally optically thick, with peak optical depths of ~0.5 (neglecting scattering), in agreement with high angular resolution observations of full disks. We performed hydrodynamical simulations with an embedded, sub-Jovian-mass planet and show that the observed multi-ringed substructure can be qualitatively explained as the outcome of the planet-disk interaction. We note, however, that the choice of the disk cooling timescale alone can significantly impact the resulting gas and dust distributions around the planet, leading to different numbers of rings and gaps and different spacings between them. We propose that the massive outer disk regions of transition disks are favorable places for planetesimals, and possibly second-generation planet formation of objects with a lower mass than the planets carving the inner cavity (typically few MJup), and that the annular substructures observed in LkCa 15 and J1610 may be indicative of planetary core formation within dust-rich pressure traps. Current observations are compatible with other mechanisms contributing to the origin of the observed substructures, in particular with regard to narrow rings generated (or facilitated) at the edge of the CO and N2 snowlines.

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High Angular Resolution Observations of Protostellar Disks

Symposium - International Astronomical Union ◽

10.1017/s0074180900108009 ◽

1994 ◽

Vol 158 ◽

pp. 387-390

Author(s):

J.-L. Monin ◽

J. Bouvier ◽

F. Malbet

Keyword(s):

Near Infrared ◽

Angular Resolution ◽

Circumstellar Disks ◽

Physical Structure ◽

Young Stellar Objects ◽

High Angular Resolution ◽

Stellar Objects ◽

Star Forming ◽

T Tauri ◽

Chromatic Properties

The existence of circumstellar disks around young stellar objects like T Tauri stars is now well accepted. Such disks would have solar system sizes and, at the distance of the nearest star forming cloud, an angular diameter of 0.01 to 1 arcsecond at most, requiring very high angular resolution to be detected. Due to the nature of the emission process in circumstellar disks and to chromatic properties of ground based observations, disk imaging is expected to be more efficient in the near infrared. Also, multi-aperture interferometry in this wavelength range (1 – 10 μm) is expected to bring considerable insight into the disks properties and evolution in revealing their inner physical structure.In this paper, we present synthetic images of circumstellar accretion disks. The images have been computed from a complete disk vertical structure model.

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Small-Angle Electron Scattering (SAES) of Polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117467 ◽

1985 ◽

Vol 43 ◽

pp. 78-79

Author(s):

Ralph Oralor ◽

Pamela Lloyd ◽

Satish Kumar ◽

W. W. Adams

Keyword(s):

Electron Scattering ◽

Small Angle ◽

Angular Resolution ◽

Structural Features ◽

Objective Lens ◽

High Angular Resolution ◽

Push Button ◽

First Case ◽

Diffraction Mode ◽

Very High

Small angle electron scattering (SAES) has been used to study structural features of up to several thousand angstroms in polymers, as well as in metals. SAES may be done either in (a) long camera mode by switching off the objective lens current or in (b) selected area diffraction mode. In the first case very high camera lengths (up to 7Ø meters on JEOL 1Ø ØCX) and high angular resolution can be obtained, while in the second case smaller camera lengths (approximately up to 3.6 meters on JEOL 1Ø ØCX) and lower angular resolution is obtainable. We conducted our SAES studies on JEOL 1ØØCX which can be switched to either mode with a push button as a standard feature.

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Large-angle convergent-beam electron-diffraction study of coherent precipitates and decorated dislocations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167470 ◽

1996 ◽

Vol 54 ◽

pp. 1002-1004

Author(s):

J.M.K. Wiezorek ◽

H.L. Fraser

Keyword(s):

Electron Diffraction ◽

Angular Resolution ◽

Large Angle ◽

Electron Diffraction Study ◽

Convergent Beam Electron Diffraction ◽

Crystal Defects ◽

High Angular Resolution ◽

Beam Electron ◽

Diffraction Plane ◽

Convergent Beam

Conventional methods of convergent beam electron diffraction (CBED) use a fully converged probe focused on the specimen in the object plane resulting in the formation of a CBED pattern in the diffraction plane. Large angle CBED (LACBED) uses a converged but defocused probe resulting in the formation of ‘shadow images’ of the illuminated sample area in the diffraction plane. Hence, low-spatial resolution image information and high-angular resolution diffraction information are superimposed in LACBED patterns which enables the simultaneous observation of crystal defects and their effect on the diffraction pattern. In recent years LACBED has been used successfully for the investigation of a variety of crystal defects, such as stacking faults, interfaces and dislocations. In this paper the contrast from coherent precipitates and decorated dislocations in LACBED patterns has been investigated. Computer simulated LACBED contrast from decorated dislocations and coherent precipitates is compared with experimental observations.

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