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Discovery of extraordinary X-ray emission from magnetospheric interaction in the unique binary stellar system Epsilon Lupi

ORAL

Abstract

Magnetic massive stars are unique stellar laboratories to understand magnetospheric physics. This is due to the fact that their magnetic fields are strong, extremely stable, and can very often be approximated as a simple dipole, which makes it relatively easy to characterize. So far there have been several studies exploring different magnetospheric phenomena occurring in solitary magnetospheres, and their effects on stellar evolution. However, only a handful of studies exist that attempt to answer the question of what happens when binarity and magnetism are acting together. The unique stellar system Epsilon Lupi is probably one of the best test-beds to investigate this effect. It is the only known short-period binary where both stars are magnetic massive stars. The orbit is mildly eccentric so that variable magnetospheric interactions (if there are any) are expected. In order to investigate this aspect, we observed the system using the Neutron Star Interior Composition Explorer Mission (NICER, an X-ray telescope on the International Space Station) at orbital phases that are close to periastron and away from the periastron. Our NICER observations revealed the presence of strong and persistent inter-star magnetospheric interaction leading to an enhanced X-ray flux at periastron, especially over the more energetic part of the spectrum. I will discuss potential scenarios that can explain these observations, and further investigations that will be needed to rule out/confirm these scenarios.

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Presenters

  • Barnali Das

    University of Delaware, USA

Authors

  • Barnali Das

    University of Delaware, USA

  • Véronique Petit

    Dept. Of Physics and Astronomy, Bartol Research Institute, University of Delaware, University of Delaware, USA

  • Michael Corcoran

    NASA/Goddard Space Flight Center, USA; The Catholic University of America, USA

  • Yael Naze

    University of Liège, Belgium

  • Asif ud-Doula

    Penn State Scranton, USA

  • Ernst Paunzen

    Masaryk University, Czech Republic

  • Gregg Wade

    Royal Military College of Canada, Canada

  • Alexandre David-Uraz

    University of Delaware, USA/Howard University, USA/NASA GSFC, USA, University of Delaware, USA; Howard University, USA; NASA/GSFC, USA

  • Coralie Neiner

    PSL University, France

  • Maurice Leutenegger

    NASA Goddard Space Flight Center, USA

  • Poonam Chandra

    NCRA-TIFR, India; NRAO, USA

  • Ayan Biswas

    Queen's University, Canada

  • David Cohen

    Swarthmore College, USA

  • Matthew Shultz

    University of Delaware, USA