UVMag: Space UV and visible spectropolarimetry

TL;DR

UVMag is a proposed space mission featuring a high-resolution UV and visible spectropolarimeter designed to study stellar magnetic fields, winds, and environments to advance understanding of stellar evolution and planetary impacts.

Contribution

This paper introduces the design considerations for a space-based UV-visible spectropolarimeter, addressing technical challenges and proposing solutions for a novel astronomical instrument.

Findings

Design options for the polarimeter are discussed.

Technical challenges in UV spectropolarimetry are identified.

The instrument aims to measure the full-Stokes vector across 117-870 nm.

Abstract

UVMag is a project of a space mission equipped with a high-resolution spectropolarimeter working in the UV and visible range. This M-size mission will be proposed to ESA at its M4 call. The main goal of UVMag is to measure the magnetic fields, winds and environment of all types of stars to reach a better understanding of stellar formation and evolution and of the impact of stellar environment on the surrounding planets. The groundbreaking combination of UV and visible spectropolarimetric observations will allow the scientists to study the stellar surface and its environment simultaneously. The instrumental challenge for this mission is to design a high-resolution space spectropolarimeter measuring the full-Stokes vector of the observed star in a huge spectral domain from 117 nm to 870 nm. This spectral range is the main difficulty because of the dispersion of the optical elements and of birefringence issues in the FUV. As the instrument will be launched into space, the polarimetric module has to be robust and therefore use if possible only static elements. This article presents the different design possibilities for the polarimeter at this point of the project.