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arXiv · 2312.04188

Zooming on the emerging ionized regions of pPNe with ALMA

C. Sánchez Contreras·D. Tafoya·J. P. Fonfría·J. Alcolea·A. Castro-Carrizo·V. Bujarrabal
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Abstract

We report on recent results from our successful and pioneering observational program with ALMA to study emerging ultracom pact HII regions of pre-Planetary Nebulae (pPNe) using mm-wavelength recombination lines (mRRLs) as new optimal tracers. We focus on our study of two poster-child pPNe, namely, M2-9 and CRL618. We reveal the structure and kinematics of the en igmatic inner nebular regions of these objects with an unprecedented angular resolution down to 20-30mas (~15-30AU). For both targets, the ionized central regions are elongated along the main symmetry axis of the large-scale nebulae, consiste nt with bipolar winds, and show notable axial velocity gradients with expansion velocities of up to ~100km/s. The H30a pr ofiles exhibit time variability, reflecting changes in the physical properties and kinematics on scales of a few years. O ur ongoing analysis employs 3D, non-LTE radiative transfer modeling, providing a detailed description of the innermost la yers of these well known pPNe with exceptional clarity.

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C. Sánchez Contreras, D. Tafoya, J. P. Fonfría, J. Alcolea, A. Castro-Carrizo, V. Bujarrabal. 2023-12-07. Zooming on the emerging ionized regions of pPNe with ALMA. https://doi.org/10.1017/s1743921324000036

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