Ultraviolet Spectropolarimetry With Polstar: Hot Star Magnetospheres

TL;DR

Polstar is a proposed NASA space telescope designed to perform ultraviolet spectropolarimetry, enabling detailed study of hot star magnetospheres and their effects on stellar evolution.

Contribution

This white paper outlines the capabilities of Polstar to provide unprecedented ultraviolet spectropolarimetric data on hot star magnetospheres.

Findings

Potential to test magnetic star spin-down hypothesis

Ability to measure plasma properties of star magnetospheres

Expected insights into stellar evolution differences

Abstract

Polstar is a proposed NASA MIDEX space telescope that will provide high-resolution, simultaneous full-Stokes spectropolarimetry in the far ultraviolet, together with low-resolution linear polarimetry in the near ultraviolet. In this white paper, we describe the unprecedented capabilities this observatory would offer in order to obtain unique information on the magnetic and plasma properties of the magnetospheres of hot stars. This would enable a test of the fundamental hypothesis that magnetospheres should act to rapidly drain angular momentum, thereby spinning the star down, whilst simultaneously reducing the net mass-loss rate. Both effects are expected to lead to dramatic differences in the evolution of magnetic vs. non-magnetic stars.