Skip to main content
Article
The Detection of Variable Radio Emission from the Fast Rotating Magnetic Hot B-Star HR 7355 and Evidence for Its X-Ray Aurorae
Monthly Notices of the Royal Astronomical Society
  • P. Leto, INAF – Osservatorio Astrofisico di Catania
  • Corrado Trigilio, National Institute of Astrophysics
  • Lidia M. Oskinova, University of Postdam
  • Richard Ignace, East Tennessee State University
  • C. S. Buemi, INAF – Osservatorio Astrofisico di Catania
  • G. Umana, INAF – Osservatorio Astrofisico di Catania
  • A. Ingallinera, INAF – Osservatorio Astrofisico di Catania
  • H. Todt, INAF – Osservatorio Astrofisico di Catania
  • F. Leone, INAF – Osservatorio Astrofisico di Catania
Document Type
Article
Publication Date
6-1-2017
Description

In this paper we investigate the multiwavelengths properties of the magnetic early B-type star HR7355. We present its radio light curves at several frequencies, taken with the Jansky Very Large Array, and X-ray spectra, taken with the XMM X-ray telescope. Modeling of the radio light curves for the Stokes I and V provides a quantitative analysis of the HR7355 magnetosphere. A comparison between HR7355 and a similar analysis for the Ap star CUVir, allows us to study how the different physical parameters of the two stars affect the structure of the respective magnetospheres where the non-thermal electrons originate. Our model includes a cold thermal plasma component that accumulates at high magnetic latitudes that influences the radio regime, but does not give rise to X-ray emission. Instead, the thermal X-ray emission arises from shocks generated by wind stream collisions close to the magnetic equatorial plane. The analysis of the X-ray spectrum of HR7355 also suggests the presence of a non-thermal radiation. Comparison between the spectral index of the power-law X-ray energy distribution with the non-thermal electron energy distribution indicates that the non-thermal X-ray component could be the auroral signature of the non-thermal electrons that impact the stellar surface, the same non-thermal electrons that are responsible for the observed radio emission. On the basis of our analysis, we suggest a novel model that simultaneously explains the X-ray and the radio features of HR7355 and is likely relevant for magnetospheres of other magnetic early type stars.

Copyright Statement

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2017 The Royal Astronomical Society. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Citation Information
P. Leto, Corrado Trigilio, Lidia M. Oskinova, Richard Ignace, et al.. "The Detection of Variable Radio Emission from the Fast Rotating Magnetic Hot B-Star HR 7355 and Evidence for Its X-Ray Aurorae" Monthly Notices of the Royal Astronomical Society Vol. 467 Iss. 3 (2017) p. 2820 - 2833 ISSN: 0035-8711
Available at: http://works.bepress.com/richard_ignace/108/