A new type of X-ray pulsar

TL;DR

This paper reports the discovery of X-ray pulsations in the massive B-type star Xi1 Canis Majoris, revealing a link between stellar pulsations and X-ray emission that challenges existing models of stellar winds and magnetism.

Contribution

It presents the first observation of pulsating X-rays from a massive star, demonstrating that stellar pulsations can influence X-ray emission, a phenomenon not previously predicted or observed.

Findings

X-ray pulsations match the star's pulsation period

Challenges current models of stellar wind and magnetism

First detection of pulsating X-rays in a massive star

Abstract

X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. Here we report the discovery of pulsating X-rays from the massive B-type star Xi1 Canis Majoris. This star is a variable of beta Cephei type and has a strong magnetic field. Our observations with the XMM-Newton telescope reveal X-ray pulsations with the same period as the fundamental stellar pulsation. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission, and their magnetism.