Apparent Motion of the Circumstellar Envelope of CQ Tau in Scattered Light

Abstract The study of spiral structures in protoplanetary disks is of great importance for understanding the processes in the disks, including planet formation. Bright spiral arms were detected in the disk of young star CQ Tau by Uyama et al. in the H and L bands. The spiral arms are located inside the gap in millimeter-sized dust, discovered earlier using Atacama Large Millimeter/submillimeter Array observations. To explain the gap, Ubeira Gabellini et al. proposed the existence of a planet with the semimajor axis of 20 au. We obtained multi-epoch observations of a spiral feature in the circumstellar envelope of CQ Tau in the I c band using a novel technique of differential speckle polarimetry. The observations covering a period from 2015 to 2021 allow us to estimate the pattern speed of the spiral: −0.°2 ± 1.°1 yr−1 (68% credible interval; positive value indicates counterclockwise rotation), assuming a face-on orientation of the disk. This speed is significantly smaller than expected for a companion-induced spiral, if the perturbing body has a semimajor axis of 20 au. We emphasize that the morphology of the spiral structure is likely to be strongly affected by shadows of a misaligned inner disk detected by Eisner et al.

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Outer spiral structure in disk galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316011091 ◽

2016 ◽

Vol 11 (S321) ◽

pp. 123-123

Author(s):

P.A. Patsis

Keyword(s):

Periodic Orbits ◽

Spiral Galaxies ◽

Spiral Structure ◽

Disk Galaxies ◽

Spiral Arms ◽

Chaotic Orbits ◽

Grand Design ◽

Pattern Speed ◽

Spiral Structures ◽

Barred Spiral Galaxies

AbstractIn several grand design barred-spiral galaxies it is observed a second, fainter, outer set of spiral arms. Typical examples of objects of this morphology can be considered NGC 1566 and NGC 5248. I suggest that such an overall structure can be the result of two dynamical mechanisms acting in the disc. The bar and both spiral systems rotate with the same pattern speed. The inner spiral is reinforced by regular orbits trapped around the stable, elliptical, periodic orbits of the central family, while the outer system of spiral arms is supported by chaotic orbits. Chaotic orbits are also responsible for a rhomboidal area surrounding the inner barred-spiral region. In general there is a discontinuity between the two spiral structures at the corotation region.

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Gap, shadows, spirals, and streamers: SPHERE observations of binary-disk interactions in GG Tauri A

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038032 ◽

2020 ◽

Vol 639 ◽

pp. A62 ◽

Cited By ~ 3

Author(s):

M. Keppler ◽

A. Penzlin ◽

M. Benisty ◽

R. van Boekel ◽

T. Henning ◽

...

Keyword(s):

Binary Systems ◽

Scattered Light ◽

Semimajor Axis ◽

Multiple Systems ◽

Outer Disk ◽

Band Filter ◽

Spiral Structures ◽

Hydrodynamical Simulations ◽

Inner Region ◽

First Time

Context. A large portion of stars is found to be part of binary or higher-order multiple systems. The ubiquity of planets found around single stars raises the question of whether and how planets in binary systems form. Protoplanetary disks are the birthplaces of planets, and characterizing them is crucial in order to understand the planet formation process. Aims. Our goal is to characterize the morphology of the GG Tau A disk, one of the largest and most massive circumbinary disks. We also aim to trace evidence for binary-disk interactions. Methods. We obtained observations in polarized scattered light of GG Tau A using the SPHERE/IRDIS instrument in the H-band filter. We analyzed the observed disk morphology and substructures. We ran 2D hydrodynamical models to simulate the evolution of the circumbinary ring over the lifetime of the disk. Results. The disk and also the cavity and the inner region are highly structured, with several shadowed regions, spiral structures, and streamer-like filaments. Some of these are detected here for the first time. The streamer-like filaments appear to connect the outer ring with the northern arc. Their azimuthal spacing suggests that they may be generated through periodic perturbations by the binary, which tear off material from the inner edge of the outer disk once during each orbit. By comparing observations to hydrodynamical simulations, we find that the main features, in particular, the gap size, but also the spiral and streamer filaments, can be qualitatively explained by the gravitational interactions of a binary with a semimajor axis of ~35 au on an orbit coplanar with the circumbinary ring.

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Exploring the dust ring in the circum-binary disc around GG Tau A

10.5194/epsc2021-831 ◽

2021 ◽

Author(s):

Claudia Toci ◽

Simone Ceppi ◽

Nicolas Cuello ◽

Giuseppe Lodato ◽

Cristiano Longarini ◽

...

Keyword(s):

Binary Systems ◽

Planet Formation ◽

Initial Conditions ◽

Scattered Light ◽

Complex Structure ◽

Semimajor Axis ◽

Continuum Emission ◽

Orbital Parameter ◽

Semi Major Axis ◽

Multiple Systems

Binaries and multiple systems are common among young stars (Reipurth et al. 2014). These stars are often surrounded by discs of gas and dust, formed due to the conservation of angular momentum of the collapsing cloud, thought to be the site of planet formation. In the case of binary systems, three discs can form: an outer disc surrounding all the stars (called circumbinary disc), and two inner discs around the stars. As circumbinary planets have recently been discovered by Kepler (see e.g., Martin 2018, Bonavita & Desidera 2020), it is crucial to understand the dynamics and evolution of circumbinary discs to better understand the initial conditions of planet formation in multiple systems. The GG Tau A system is an example of a young multiple T Tauri star. The binary is surrounded by a bright disc, observed in the continuum emission at different wavelengths (see e.g., Guilloteau et al. 1999; Dutrey et al. 2014; Phuong et al. 2020b) and in scattered light (e.g., Duchene et al. 2014, Keppler et al. 2020). The disc extends in the dust from 180 to 280 au from the center of mass, and in the gas up to 850 au. The inner (<180 au) part is depleted in gas and dust. Scattered light images show a complex structure in the inner part of the disc, with arcs and filamentary structures connecting the outer ring with the arcs and three shadows. Two different configurations are possible fitting the proper motion data for the system: a co-planar case with a low eccentricity binary with a semi-major axis of 34 au, explored by Cazzoletti et al. 2017 and Keppler et al. 2020, and a misaligned case (i=30) with an eccentric binary (e=0.45) and a wider semimajor axis of 60 au (Aly et al.2018). At the state of the art, all these analyses focused on the gas dynamics only. We will show the results of new 3D SPH simulations of dust and gas performed with the code PHANTOM, devised to test the two possible scenarios. We will describe the dynamics of the system in the two cases, comparing our models with observational results in order to better constraint the orbital parameter of the GG Tau A system. Our predictions will guide future observing campaigns and shed light on the complex evolution of discs in triple stellar systems. &#160;

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Dynamical imprint of interstellar gas on persistence of spiral structure in galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317006494 ◽

2017 ◽

Vol 13 (S334) ◽

pp. 296-297

Author(s):

Soumavo Ghosh ◽

Chanda J. Jog

Keyword(s):

Time Scale ◽

Spiral Structure ◽

Density Wave ◽

Disk Galaxies ◽

Interstellar Gas ◽

Spiral Arms ◽

Pattern Speed

AbstractThe persistence of the spiral structure in disk galaxies has long been debated. In this work, we investigate the dynamical influence of interstellar gas on the persistence of the spiral arms in disk galaxies. We show that the gas helps the spiral arms to survive for longer time-scale (~ a few Gyr). Also, we show that the addition of gas in calculation is necessary for getting a stable density wave corresponding to the observed pattern speed of the spiral arms.

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Direct imaging of irregular satellite discs in scattered light

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa195 ◽

2020 ◽

Vol 492 (4) ◽

pp. 5709-5720

Author(s):

Loic Nassif-Lachapelle ◽

Daniel Tamayo

Keyword(s):

Near Infrared ◽

Thermal Emission ◽

Scattered Light ◽

Semimajor Axis ◽

Detection Methods ◽

Direct Imaging ◽

Irregular Satellites ◽

Long Period ◽

Wide Range ◽

Collisional Evolution

ABSTRACT Direct imaging surveys have found that long-period super-Jupiters are rare. By contrast, recent modelling of the widespread gaps in protoplanetary discs revealed by Atacama Large Millimetre Array suggests an abundant population of smaller Neptune to Jupiter-mass planets at large separations. The thermal emission from such lower-mass planets is negligible at optical and near-infrared wavelengths, leaving only their weak signals in reflected light. Planets do not scatter enough light at these large orbital distances, but there is a natural way to enhance their reflecting area. Each of the four giant planets in our Solar system hosts swarms of dozens of irregular satellites, gravitationally captured planetesimals that fill their host planets’ spheres of gravitational influence. What we see of them today are the leftovers of an intense collisional evolution. At early times, they would have generated bright circumplanetary debris discs. We investigate the properties and detectability of such irregular satellite discs (ISDs) following models for their collisional evolution from Kennedy & Wyatt (2011). We find that the scattered light signals from such ISDs would peak in the 10–100 au semimajor axis range implied by ALMA, and can render planets detectable over a wide range of parameters with upcoming high-contrast instrumentation. We argue that future instruments with wide fields of view could simultaneously characterize the atmospheres of known close-in planets, and reveal the population of long-period Neptune–Jupiter mass exoplanets inaccessible to other detection methods. This provides a complementary and compelling science case that would elucidate the early lives of planetary systems.

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STRUCTURES OUT OF CHAOS IN BARRED-SPIRAL GALAXIES

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127412300297 ◽

2012 ◽

Vol 22 (09) ◽

pp. 1230029 ◽

Cited By ~ 2

Author(s):

P. A. PATSIS

Keyword(s):

Near Infrared ◽

Spiral Galaxies ◽

Morphological Features ◽

Infrared Images ◽

Chaotic Motions ◽

Spiral Arms ◽

Gravitational Fields ◽

Pattern Speed ◽

Barred Spiral Galaxies ◽

Kinematical Data

We review the dynamical mechanisms we have found to support the morphological features in barred-spiral galaxies based on chaotic motions of stars in their gravitational fields. These morphological features are the spiral arms, that emerge out of the ends of the bar, but also shape the bar itself. The potentials used have been estimated directly from near-infrared images of barred-spiral galaxies. In this paper, we present the results from the study of the dynamics of the potentials of the galaxies NGC 4314, NGC 1300 and NGC 3359. The main unknown parameter in our models is the pattern speed of the system Ωp. By varying Ωp, we have investigated several cases trying to match the results of our modeling with available photometrical and kinematical data. We found realistic models with stars on spirals in chaotic motion, while their bars are built by stars usually on regular orbits. However, we also encountered cases, where a major part of trajectories of the stars even in the bar is chaotic as well. Finally, we examined the gas dynamics of barred-spiral systems, and found that the presence of gas reinforces the intensity of the "chaotic" spiral arms.

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Magnetic Fields and the Interstellar Medium in Spiral Arms

Symposium - International Astronomical Union ◽

10.1017/s0074180900233743 ◽

1996 ◽

Vol 171 ◽

pp. 456-456

Author(s):

M. Urbanik ◽

M. Soida ◽

R. Beck

Keyword(s):

Magnetic Fields ◽

Interstellar Medium ◽

Radio Telescope ◽

High Frequency ◽

Spiral Galaxies ◽

Total Power ◽

Spiral Arms ◽

Dust Lane ◽

Radio Studies ◽

Spiral Structures

We performed the high frequency radio studies of spiral galaxies using the 100 m MPIfR radio telescope at 10.55 GHz. Two objects: NGC 4254 and NGC 3627 possess perturbed spiral structures while two others, NGC 3521 and NGC 5055 are flocculent objects, lacking organized spiral patterns. NGC 3521 possesses also a peculiar dust lane. For NGC 4254, NGC 3627 and NGC 5055 deep polarization maps were made, for NGC 3521 the total power data only were analyzed (see Urbanik et al. 1989).

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Resolved Scattered Light Images of the Edge-On Protoplanetary Disk ESO Hα 569

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313007953 ◽

2013 ◽

Vol 8 (S299) ◽

pp. 76-77

Author(s):

S. Wolff ◽

M. Perrin ◽

K. Stapelfeldt ◽

G. Duchêne ◽

J. Krist ◽

...

Keyword(s):

Scattered Light ◽

Spectral Energy Distribution ◽

Volume Density ◽

Protoplanetary Disk ◽

Young Star ◽

Outer Radius ◽

Spectral Energy ◽

Distribution Data ◽

Nearby Star ◽

Star Forming

AbstractWe present detailed models of the edge-on protoplanetary disk ESO Hα 569 (SSTgbs J111110.7-764157) from resolved scattered light images from HST and a complete spectral energy distribution. Data was obtained as part of an HST campaign to catalogue edge-on disks around young stars in nearby star forming regions (HST program 12514, PI: Karl Stapelfeldt). We confirm that this object is an optically thick edge-on disk around a young star with an outer radius of 125 AU. Using full radiative transfer models, we probe the distribution of dust grains and overall shape of the disk (inclination, scale height, dust mass, maximum particle size, inner radius, flaring exponent and surface/volume density exponent).

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Evidence for a massive dust-trapping vortex connected to spirals

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834006 ◽

2018 ◽

Vol 619 ◽

pp. A161 ◽

Cited By ~ 32

Author(s):

P. Cazzoletti ◽

E. F. van Dishoeck ◽

P. Pinilla ◽

M. Tazzari ◽

S. Facchini ◽

...

Keyword(s):

Large Scale ◽

Scattered Light ◽

Continuum Emission ◽

Asymmetric Structure ◽

Outer Planet ◽

Dust Trapping ◽

Spiral Arms ◽

Multi Wavelength ◽

The Asymmetry ◽

Dust Distribution

Context. Spiral arms, rings and large scale asymmetries are structures observed in high resolution observations of protoplanetary disks, and it appears that some of the disks showing spiral arms in scattered light also show asymmetries in millimeter-sized dust. HD 135344B is one such disk. Planets are invoked as the origin of these structures, but no planet has been observed so far and upper limits are becoming more stringent with time. Aims. We want to investigate the nature of the asymmetric structure in the HD 135344B disk in order to understand the origin of the spirals and of the asymmetry seen in this disk. Ultimately, we aim to understand whether or not one or more planets are needed to explain such structures. Methods. We present new ALMA sub-0.1′′ resolution observations at optically thin wavelengths (λ = 2.8 and 1.9 mm) of the HD 135344B disk. The high spatial resolution allows us to unambiguously characterize the mm-dust morphology of the disk. The low optical depth of continuum emission probes the bulk of the dust content of the vortex. Moreover, we have combined the new observations with archival data at shorter wavelengths to perform a multi-wavelength analysis and to obtain information about the dust distribution and properties inside the observed asymmetry. Results. We resolve the asymmetric disk into a symmetric ring + asymmetric crescent, and observe that (1) the spectral index strongly decreases at the centre of the vortex, consistent with the presence of large grains; (2) for the first time, an azimuthal shift of the peak of the vortex with wavelength is observed; (3) the azimuthal width of the vortex decreases at longer wavelengths, as expected for dust traps. These features allow confirming the nature of the asymmetry as a vortex. Finally, under the assumption of optically thin emission, a lower limit to the total mass of the vortex is 0.3MJupiter. Considering the uncertainties involved in this estimate, it is possible that the actual mass of the vortex is higher and possibly within the required values (~4 MJupiter) to launch spiral arms similar to those observed in scattered light. If this is the case, then explaining the morphology does not require an outer planet.

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