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We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the mm emission of this disk with the highest angular resolution so far ($0rlap.12times0rlap.09$, or 14 au$times$11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emission at a radius of $sim25$ au tracing the outer edge of the inner gap. This ring presents an asymmetric morphology that could be produced by dynamical interactions between the disk and forming planets. Additionally, the azimuthally averaged radial intensity profiles of the 7 and 9 mm images confirm the presence of the previously reported gap at $sim45$ au, and reveal a new gap at $sim85$ au. We analyzed archival DCO$^+$(3-2) and C$^{18}$O(2-1) ALMA observations, showing that the CO snowline is located very close to this third outer gap. This suggests that growth and accumulation of large dust grains close to the CO snowline could be the mechanism responsible for this proposed outer gap. Finally, a compact source of emission is detected at 7 mm, 9 mm, and 3 cm toward the center of the disk. Its flux density and spectral index indicate that it is dominated by free-free emission from ionized gas, which could be associated with either the photoionization of the inner disk, an independent object, or an ionized jet.
We present a detailed multi-wavelength characterization of the multi-ring disk of HD 169142. We report new ALMA observations at 3 mm and analyze them together with archival 0.89 and 1.3 mm data. Our observations resolve three out of the four rings in
The high spatial and line sensitivity of ALMA opens the possibility of resolving emission from molecules in circumstellar disks. With an understanding of physical conditions under which molecules have high abundance, they can be used as direct tracer
To characterize the mechanisms of planet formation it is crucial to investigate the properties and evolution of protoplanetary disks around young stars, where the initial conditions for the growth of planets are set. Our goal is to study grain growth
This work aims to understand which midplane conditions are probed by the DCO$^+$ emission in the disk around the Herbig Ae star HD 169142. We explore the sensitivity of the DCO$^+$ formation pathways to the gas temperature and the CO abundance. The D
Snowlines are key ingredients for planet formation. Providing observational constraints on the locations of the major snowlines is therefore crucial for fully connecting planet compositions to their formation mechanism. Unfortunately, the most import