Early B-type stars with resolved Zeeman split lines

TL;DR

This paper discusses the detection and analysis of resolved Zeeman split lines in early B-type stars, revealing their magnetic field properties despite expectations of Zeeman splitting being absent in such hot, fast-rotating stars.

Contribution

It reports the discovery of early B-type stars with magnetically split lines, expanding the understanding of magnetic phenomena in hot, massive stars.

Findings

Detection of Zeeman split lines in early B-type stars

Magnetic fields in these stars can be diagnosed through spectral line analysis

Challenges previous assumptions about Zeeman splitting in hot, fast rotators

Abstract

Almost three decades ago, Mathys (1990) demonstrated the importance of studying Ap stars showing resolved Zeeman split Fe II 6147.7 and 6149.2 lines. Such Zeeman split lines can be seen in stars whose projected rotational velocity is sufficiently small and whose magnetic field is strong enough to exceed the rotational Doppler broadening. Observations of resolved Zeeman split lines permit the diagnosis of the average of the modulus of the magnetic field over the visible stellar hemisphere. Although Zeeman splitting is not expected in faster rotating hot massive stars, we have recently been discovering early B-type stars displaying magnetically split spectral lines.