A&A 635, A196 (2020) Astronomy https://doi.org/10.1051/0004-6361/201936990 & © ESO 2020 Astrophysics The origin of tail-like structures around protoplanetary disks? Eduard I. Vorobyov1,2,3, Alexandr M. Skliarevskii2, Vardan G. Elbakyan2,4, Michihiro Takami5, Hauyu Baobab Liu5, Sheng-Yuan Liu5, and Eiji Akiyama6 1 University of Vienna, Department of Astrophysics, Vienna 1180, Austria e-mail:
[email protected] 2 Research Institute of Physics, Southern Federal University, Rostov-on-Don 344090, Russia 3 Ural Federal University, 51 Lenin Str., 620051 Ekaterinburg, Russia 4 Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden 5 Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No.1, Sec. 4, Roosevelt Rd, Taipei 10617, Taiwan, ROC 6 Institute for the Advancement of Higher Education, Hokkaido University, Kita17, Nishi8, Kita-ku, Sapporo 060-0817, Japan Received 25 October 2019 / Accepted 24 January 2020 ABSTRACT Aims. We study the origin of tail-like structures recently detected around the disk of SU Aurigae and several FU Orionis-type stars. Methods. Dynamic protostellar disks featuring ejections of gaseous clumps and quiescent protoplanetary disks experiencing a close encounter with an intruder star were modeled using the numerical hydrodynamics code FEOSAD. Both the gas and dust dynamics were taken into account, including dust growth and mutual friction between the gas and dust components. Only plane-of-the-disk encounters were considered. Results. Ejected clumps produce a unique type of tail that is characterized by a bow-shock shape. Such tails originate from the supersonic motion of ejected clumps through the dense envelope that often surrounds young gravitationally unstable protostellar disks.