摘要：Context. Gaps, cavities, and rings in circumstellar disks are signposts
of disk evolution and planet-disk interactions. We follow the recent suggestion that
Herbig Ae/Be disks with a flared disk harbor a cavity, and investigate the disk around HD
97048.
Aims. We aim to resolve the 34 ± 4 AU central cavity that has been predicted and to investigate
the structure of the disk.
Methods. We imaged the disk around HD 97048 using ALMA at 0.85 mm and
2.94 mm and ATCA (multiple frequency) observations. Our observations also include the
12CO J = 1−0,
12CO J = 3−2 and
HCO+ J = 4−3 emission lines.
Results. A central cavity in the disk around HD 97048 is resolved with a
40−46 AU radius. Additional
radial structure present in the surface brightness profile can be accounted for either by
an opacity gap at 90 AU or by an additional emitting ring at 150 AU. The continuum
emission tracing the dust in the disk is detected out to 355 AU. The
12CO J = 3−2 disk is detected 2.4 times farther out.
The 12CO emission can be traced down to ≈10 AU scales. Apparent non-Keplerian
kinematics are detected inside the cavity on the
HCO+ J = 4−3 velocity map. The mm spectral index
measured from ATCA observations suggests that grain growth has occurred in the HD 97048
disk. Finally, we resolve a highly inclined disk out to 150 AU around the nearby 0.5
M⊙ binary ISO-ChaI 126.
Conclusions. The data presented here reveal a cavity in the disk of HD
97048, and prominent radial structure in the surface brightness. The cavity size varies
for different continuum frequencies and gas tracers. The gas inside the cavity follows
non-Keplerian kinematics seen in HCO+ emission. The variable
cavity size along with the kinematical signature suggests the presence of a substellar
companion or a massive planet inside the cavity.
关键词：protoplanetary disks;stars: variables: T Tauri, Herbig Ae/Be;stars: individual: HD 97048
