Tau Sco: discovery of the clones

TL;DR

This paper discusses the discovery of tau Sco clones, early B-type stars with similar UV spectra and magnetic fields, highlighting their unique wind properties and the ongoing efforts to understand their magnetic topology.

Contribution

It reports the identification of tau Sco analogues with confirmed magnetic fields, advancing understanding of magnetic influences on stellar wind anomalies.

Findings

Detection of magnetic fields in tau Sco analogues

Confirmation of UV spectral similarity to tau Sco

Ongoing efforts to map magnetic topology

Abstract

The B0.2 V magnetic star tau Sco stands out from the larger population of massive magnetic OB stars due to its high X-ray activity and remarkable wind, apparently related to its peculiar magnetic field - a field which is far more complex than the mostly-dipolar fields usually observed in magnetic OB stars. tau Sco is therefore a puzzling outlier in the larger picture of stellar magnetism - a star that still defies interpretation in terms of a physically coherent model. Recently, two early B-type stars were discovered as tau Sco analogues, identified by the striking similarity of their UV spectra to that of tau Sco, which was - until now - unique among OB stars. We present the recent detection of their magnetic fields by the MiMeS collaboration, reinforcing the connection between the presence of a magnetic field and wind anomalies (Petit et al. 2010). We will also present ongoing observational efforts undertaken to establish the precise magnetic topology, in order to provide additional constrains for existing models attempting to reproduce the unique wind structure of tau Sco-like stars.