Discovery of the shortest rotational period, non-degenerate, magnetic massive star by the MiMeS Collaboration

TL;DR

This paper reports the discovery of the fastest-rotating, non-degenerate magnetic star, HR 5907, with a period of 0.50833 days, revealing a structured magnetosphere through spectropolarimetric observations.

Contribution

It presents the detection and characterization of the shortest rotational period for a non-degenerate magnetic star, expanding understanding of stellar magnetism and rotation.

Findings

HR 5907 has a rotational period of 0.50833 days.

It exhibits a strong, organized magnetic field.

The star shows emission line variability indicating a structured magnetosphere.

Abstract

We discuss the recent detection of a strong, organized magnetic field in the bright, broad-line B2V star, HR 5907, using the ESPaDOnS spectropolarimeter on the CFHT as part of the Magnetism in Massive Stars (MiMeS) survey. We find a rotational period of 0.50833 days, making it the fastest-rotating, non-degenerate magnetic star ever detected. Like the previous rapid-rotation record holder HR 7355 (also discovered by MiMeS: Oksala et al. 2010, Rivinius et al. 2010), this star shows emission line variability that is diagnostic of a structured magnetosphere.