Tracing large-scale structures in circumstellar disks with ALMA

Demidova

et al. 2015

A&A

Context. During the past decade circumbinary disks have been discovered around various young binary stars. Hydrodynamical calculations indicate that the gravitational interaction between the central binary star and the surrounding disk results in global perturbations of the disk density profile. Aims. We study the observability of characteristic large-scale disk structures resulting from the binary-disk interaction in the case of close binary systems. Methods. We derived the structure of circumbinary disks from smoothed-particle hydrodynamic simulations. Subsequently, we performed radiative transfer simulations to obtain scattered light and thermal reemission maps. We investigated the influence of the binary mass ratio, the inclination of the binary orbit relative to the disk midplane, and the eccentricity of the binary orbit on observational quantities. Results. We find that ALMA will allow tracing asymmetries of the inner edge of the disk and potentially resolving spiral arms if the disk is seen face-on. For an edge-on orientation, ALMA will allow detecting perturbations in the disk density distribution through asymmetries in the radial brightness profile. Through the asymmetric structure of the disks, areas are formed with a temperature 2.6 times higher than at the same location in equivalent unperturbed disks. The time-dependent appearance of the density waves and spiral arms in the disk affects the total re-emission flux of the object by a few percent.

Section: Resultsmentioning

confidence: 99%

“…Since the SPH calculations are mainly sensitive to the binary mass ratio q, a giant planet (M planet = 10 M Jup ) around a solartype star (M = 1 M ) will induce similar perturbations in the disk (for a detailed study see Ruge et al 2013).…”

Section: Circumbinary Disks In An Edge-on Orientationmentioning

confidence: 99%

Structures in circumbinary disks: Prospects for observability

Demidova

et al. 2015

A&A

“…A major fraction of the simulations and summarizing overview charts are available online at http://www1.astrophysik.uni-kiel.de/~placid. For further information see Ruge et al (accepted by A&A) [2].…”

Section: Discussionmentioning

confidence: 99%

“…Through the unprecedented resolution and sensitivity of ALMA in the (sub)mm wavelength range the expected detailed observations of planet-disc interaction and global disc structures will deepen our understanding of the planet formation and disc evolution process. This article presents a summary of the study published by [2] a …”

mentioning

confidence: 99%

Tracing Planets in Circumstellar Discs

Uribe

et al. 2013

EPJ Web of Conferences

Abstract. Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (sub)mm wavelength range for the Atacama Large (Sub)Millimeter Array (ALMA). On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (sub)mm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20 • . The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses), nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67 · 10 −7 M and 4.10 · 10 −2 M , six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4 . . . 2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplanetary discs (0.1 M . . . 0.001 M ) the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67 · 10 −6 M and trace gaps in discs with 2.67 · 10 −4 M with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of magnetic fields [1]. We also find, that zonal flows resulting from magneto-rotational instability (MRI) create gap-like structures in the disc re-emission radiation which are observable with ALMA. Through the unprecedented resolution and sensitivity of ALMA in the (sub)mm wavelength range the expected detailed observations of planet-disc interaction and global disc structures will deepen our understanding of the planet formation and disc evolution process. This article presents a summary of the study published by [2] a

“…In contrast, our approach is based on 3D HD calculations and follow-up radiative transfer calculations. The resulting scattered light images are compared to the outcome of a corresponding study concerning thermal disk re-emission (Ruge et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Planet-induced disk structures: A comparison between (sub)mm and infrared radiation

Uribe

et al. 2014

A&A

Context. Young giant planets, which are embedded in a circumstellar disk, will significantly perturb the disk density distribution. This effect can potentially be used as an indirect tracer for planets. Aims. We investigate the feasibility of observing planet-induced gaps in circumstellar disks in scattered light. Methods. We perform 3D hydrodynamical disk simulations combined with subsequent radiative transfer calculations in scattered light for different star, disk, and planet configurations. The results are compared to those of a corresponding study for the (sub)mm thermal re-emission. Results. The feasibility of detecting planet-induced gaps in scattered light is mainly influenced by the optical depth of the disk and therefore by the disk size and mass. Planet-induced gaps are in general only detectable if the photosphere of the disks is sufficiently disturbed. Within the limitations given by the parameter space here considered, we find that gap detection is possible in the case of disks with masses below ∼10 −4···−3 M . Compared to the disk mass that marks the lower Atacama Large (Sub)Millimeter Array (ALMA) detection limit for the thermal radiation re-emitted by the disk, it is possible to detect the same gap both in re-emission and scattered light only in a narrow range of disk masses around ∼10 −4 M , corresponding to 16% of cases considered in our study.