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

Abstract

<jats:p><jats:italic>Context.</jats:italic> 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.</jats:p> <jats:p><jats:italic>Aims.</jats:italic> 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.</jats:p> <jats:p><jats:italic>Methods.</jats:italic> We obtained observations in polarized scattered light of GG Tau A using the SPHERE/IRDIS instrument in the <jats:italic>H</jats:italic>-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.</jats:p> <jats:p><jats:italic>Results.</jats:italic> 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.</jats:p>

A faint companion around CrA-9: protoplanet or obscured binary?

“…This estimate is significantly larger than inferred for the PDS 70 planets (Haffert et al 2019;Hashimoto et al 2020), although the latter may be at a more advanced stage considering they have already cleared a wide and deep gap (e.g. Hashimoto et al 2011;Dong et al 2012;Keppler et al 2020). The inferred mass accretion rate is similar to what has been predicted from magneto-hydrodynamical simulations of accreting sub-Jovian planets embedded in the protoplanetary disc (e.g.…”

Architecture of Hierarchical Stellar Systems and Their Formation

“…The masses of these stars range from 0.2 to 0.65 M . A recent paper by Keppler et al [94] explores the structure of the disk around Aa,Ab (cavity, filaments, shadows, accretion streams), trying to infer orientations of the unresolved circumstellar disks.…”

SCExAO/CHARIS High-contrast Imaging of Spirals and Darkening Features in the HD 34700 A Protoplanetary Disk

“…The single shadow is reminiscent of the ones observed in the circumbinary disk of GGTauA, which includes a close central binary similar to HD34700A (Itoh et al 2002(Itoh et al , 2014, and in the transition disk of HD169142 (Quanz et al 2013;Bertrang et al 2018). Several explanations for the single shadow of GG Tau have been proposed, including a dense clump in an accretion stream onto one component of the central binary, or a circumplanetary disk surrounding a protoplanet located in the cavity (Krist et al 2002;Canovas et al 2017) as well as circumstellar disks around GG Tau Aa/b (Brauer et al 2019;Keppler et al 2020).…”

“…Although their model showed good agreement with polarimetric data in the J band, it had some differences between GPI-based JH-band total intensity and H-band polarized intensity. Another intriguing feature in the HD 34700 A disk is its spiral features: previous high angular resolution observations have indicated a variety of morphology in disks at various evolutionary stages (e.g., AB Aur, SAO 206462, MWC 758, HD 100453, HD 100546, HD 142527, Elias 2-27, CQ Tau, GG Tau;Hashimoto et al 2011;Muto et al 2012;Grady et al 2013;Avenhaus et al 2014;Currie et al 2015;Wagner et al 2015;Pérez et al 2016;Keppler et al 2020;Uyama et al 2020). Among these disks this object has the largest number of spirals in a disk, the mechanism for which is still unclear.…”