| |
 |
| Paper: |
Exploring the Emerging Ionized Cores of Pre-Planetary Nebulae with ALMA |
| Volume: |
536, The Twelfth Pacific Rim Conference on Stellar Astrophysics |
| Page: |
123 |
| Authors: |
Contreras, C. S.; Tafoya, D.; Fonfria, J. P.; Alcolea, J.; Castro-Carrizo, A.; Bujarrabal, V. |
| Abstract: |
We report on recent results from our successful and pioneering observational program with ALMA to study emerging ultracompact ionized regions of pre-Planetary Nebulae (pPNe). By utilizing mm-wavelength recombination lines (mm-RRLs) as novel tracers, we are able to delve deeper than ever before into the inner workings of these fascinating objects. In this contribution, I will focus on two objects: MWC 922 (Sánchez Contreras et al. 2019) and M 2-9 (Sánchez Contreras et al., in preparation). We unveil the structure and kinematics of the elusive inner nebular regions of these objects with an unprecedented angular resolution of 20-30mas (i.e., down to ∼15-30 au linear scales). In the case of MWC 922, our observations resolved a rotating fast bipolar wind and disk system at the core, offering for the first-time empirical evidence of rotation within a high-velocity (∼ 100 km s−1) outflow. For M 2-9, the ionized central region is elongated along the main symmetry axis of the large-scale nebulae and show notable axial velocity gradient with expansion velocities of up to ∼ 100 km s−1, consistent with a bipolar jet. For both targets, the H30α and H39α profiles exhibit time variability, reflecting changes in the physical properties and kinematics of the present-day ejections on scales of a few years. Our analysis includes 3D non-LTE radiative transfer modeling, which allows us to describe with unparalleled detail the physical conditions in the inner layers of these objects and advance our understanding of the development of multi-scale asymmetries in these late evolutionary stages. |
|
|
|
|
|
