British Astronomical Association
Supporting amateur astronomers since 1890

Secondary menu

Main menu

BAA Meeting calendar

BAA Autumn Webinar

Date:
Saturday, 2021, September 4 - 11:00 to 12:00

We are pleased to announce a Autumn Webinar in lieu of the postponed Autumn meeting in Leeds. There will be one session of about an hour with a talk followed by Q&A.

Click here to join the meeting via Zoom: https://us02web.zoom.us/j/82688033550?pwd=ZTduSUI1UnBlcjR2UGYyZGtOb3gydz09

For anyone who does not wish to join via Zoom or is unable to install the software, then we will also be streaming the webinar on our BAA YouTube channel. Please note you will be unable to ask questions via YouTube.

11:00 Dr Manisha Shrestha - “Stellar wind bow shock: a laboratory to study stellar wind and interstellar medium”

Dr Manisha Shrestha is a Postdoctoral Fellow at Astrophysics Research Institute.

Zeta Ophiuchi - Image by WISE NASA/JPL-Caltech/UCLA

Synopsis: - Massive stars lose mass primarily via radiation-driven stellar winds. Mass loss from massive stars impact their evolution as well as the evolution and composition of the surrounding interstellar medium (ISM). When stellar wind from a massive star interacts with the local ISM or the wind of a companion star, it forms structures of circumstellar material (CSM). Starlight scattering from electrons or dust in this CSM creates polarization signatures, which have been observed in different types of massive stars. Stellar wind bow shocks are regions of enhanced density formed by the interaction of a stellar wind from a fast-moving star and its local ISM. Because of the bow shock's aspherical shape, light scattering via free electrons and dust within it produces a net polarization signal even if the region is spatially unresolved. This polarization signal encodes the shape, composition, opacity, density, and ionization state of the material within the structure. I will discuss how polarization analysis reveal various aspects of stellar wind and ISM. In addition, I will present a technique we have used to decipher properties of stellar wind and ISM via polarization of stellar wind bow shocks.