TY - JOUR
T1 - SPIRAL WAVES TRIGGERED by SHADOWS in TRANSITION DISKS
AU - Montesinos, Matías
AU - Perez, Sebastian
AU - Casassus, Simon
AU - Marino, Sebastian
AU - Cuadra, Jorge
AU - Christiaens, Valentin
N1 - Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved..
PY - 2016/5/20
Y1 - 2016/5/20
N2 - Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the development of spiral arms. Using 2D simulations, we follow the evolution of a gaseous disk passively heated by the central star, under the periodic forcing of shadows with an opening angle of ∼28°. With a lower pressure under the shadows, each crossing results in a variable azimuthal acceleration, which in time develops into spiral density waves. Their pitch angles evolve from Π ∼ 15°-22° at the onset, to ∼11°-14°, over ∼65 au to 150 au. Self-gravity enhances the density contrast of the spiral waves, as also reported previously for spirals launched by planets. Our control simulations with unshadowed irradiation do not develop structures, except for a different form of spiral waves seen at later times only in the gravitationally unstable control case. Scattered light predictions in the H-band show that such illumination spirals should be observable. We suggest that spiral arms in the case-study transition disk HD 142527 could be explained as a result of shadowing from the tilted inner disk.
AB - Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the development of spiral arms. Using 2D simulations, we follow the evolution of a gaseous disk passively heated by the central star, under the periodic forcing of shadows with an opening angle of ∼28°. With a lower pressure under the shadows, each crossing results in a variable azimuthal acceleration, which in time develops into spiral density waves. Their pitch angles evolve from Π ∼ 15°-22° at the onset, to ∼11°-14°, over ∼65 au to 150 au. Self-gravity enhances the density contrast of the spiral waves, as also reported previously for spirals launched by planets. Our control simulations with unshadowed irradiation do not develop structures, except for a different form of spiral waves seen at later times only in the gravitationally unstable control case. Scattered light predictions in the H-band show that such illumination spirals should be observable. We suggest that spiral arms in the case-study transition disk HD 142527 could be explained as a result of shadowing from the tilted inner disk.
KW - accretion, accretion disks
KW - hydrodynamics
KW - methods: numerical
KW - planets and satellites: dynamical evolution and stability
KW - protoplanetary disks
UR - http://www.scopus.com/inward/record.url?scp=84973160180&partnerID=8YFLogxK
U2 - 10.3847/2041-8205/823/1/L8
DO - 10.3847/2041-8205/823/1/L8
M3 - Article
AN - SCOPUS:84973160180
SN - 2041-8205
VL - 823
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L8
ER -