Issue |
A&A
Volume 639, July 2020
|
|
---|---|---|
Article Number | A121 | |
Number of page(s) | 16 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202038027 | |
Published online | 20 July 2020 |
Annular substructures in the transition disks around LkCa 15 and J1610★
1
European Southern Observatory,
Karl-Schwarzschild-Str. 2,
85748
Garching,
Germany
e-mail: stefano.facchini@eso.org
2
Unidad Mixta Internacional Franco-Chilena de Astronomía, CNRS, UMI3386, Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515,
Las Condes,
Santiago,
Chile
3
Univ. Grenoble Alpes, CNRS, IPAG,
38000
Grenoble,
France
4
Earth and Planets Laboratory, Carnegie Institution for Science,
5241 Broad Branch Road NW,
Washington,
DC
20015,
USA
5
NRAO,
520 Edgemont Rd,
Charlottesville,
VA
22903,
USA
6
Flatiron Institute, Simons Foundation,
162 Fifth Ave,
New York,
NY
10010,
USA
7
The Graduate University for Advanced Studies, SOKENDAI, Shonan Village, Hayama, Miura,
Kanagawa
240-0193,
Japan
8
Max Planck Institute for Astronomy,
Königstuhl 17,
69117
Heidelberg,
Germany
9
Center for Astrophysics | Harvard & Smithsonian,
60 Garden Street,
Cambridge,
MA
02138,
USA
10
Department of Physics and Astronomy, Rice University,
6100 Main Street, MS-108,
Houston,
TX
77005,
USA
11
Department of Physics and Astronomy, University of North Carolina at Chapel Hill,
Chapel Hill,
NC
27599,
USA
Received:
26
March
2020
Accepted:
5
May
2020
We present high-resolution millimeter continuum ALMA observations of the disks around the T Tauri stars LkCa 15 and 2MASS J16100501-2132318 (hereafter, J1610). These transition disks host dust-depleted inner regions, which have possibly been carved by massive planets, and they are of prime interest to the study of the imprints of planet-disk interactions. While at moderate angular resolution, they appear as a broad ring surrounding a cavity, the continuum emission resolves into multiple rings at a resolution of ~60 × 40 mas (~7.5 au for LkCa 15, ~6 au for J1610) and ~7 μJy beam−1 rms at 1.3 mm. In addition to a broad extended component, LkCa 15 and J1610 host three and two narrow rings, respectively, with two bright rings in LkCa 15 being radially resolved. LkCa 15 possibly hosts another faint ring close to the outer edge of the mm emission. The rings look marginally optically thick, with peak optical depths of ~0.5 (neglecting scattering), in agreement with high angular resolution observations of full disks. We performed hydrodynamical simulations with an embedded, sub-Jovian-mass planet and show that the observed multi-ringed substructure can be qualitatively explained as the outcome of the planet-disk interaction. We note, however, that the choice of the disk cooling timescale alone can significantly impact the resulting gas and dust distributions around the planet, leading to different numbers of rings and gaps and different spacings between them. We propose that the massive outer disk regions of transition disks are favorable places for planetesimals, and possibly second-generation planet formation of objects with a lower mass than the planets carving the inner cavity (typically few MJup), and that the annular substructures observed in LkCa 15 and J1610 may be indicative of planetary core formation within dust-rich pressure traps. Current observations are compatible with other mechanisms contributing to the origin of the observed substructures, in particular with regard to narrow rings generated (or facilitated) at the edge of the CO and N2 snowlines.
Key words: accretion, accretion disks / protoplanetary disks / submillimeter: planetary systems / stars: individual: LkCa 15 / stars: individual: J1610
The reduced images are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/639/A121
© ESO 2020
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