Unveiling the Circumstellar Regions of Thermally Pulsing Asymptotic Giant Branch Stars with the Gemini Planet Imager
Abstract
The Thermally-Pulsating (TP-) period of Asymptotic Giant Branch (AGB) stars is one of the least understood phases of stellar evolution. Understanding the TP-AGB phase mass-loss and molecule formation (in the stars' stellar winds) provides crucial insights into the composition of the interstellar medium and stellar populations of galaxies. We have commenced a high-contrast imaging program of TP-AGB stars to study morphologies and dust and gas properties of their circumstellar envelopes (CSEs). High-contrast polarimetric observations at 14 mas angular resolution were performed using the Gemini Planet Imager to study the inner regions of CSEs (~50-800 AU) around five TP-AGB stars. We resolved polarimetric H-band (λcen = 1.65 μm) images of the inner CSE around the AGB star W Pic. We apply radiative transfer RADMC simulations to determine W Pic's stellar mass-loss rate, dust formation rates, wind speeds, and asymmetries.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23316304S