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.

*BD and VP acknowledge support by the National Aeronautics and Space Administration under grant No. NASA 80NSSC21K0134.BD acknowledges support from the Bartol Research Institute.VP acknowledges support by the National Science Foundation under Grant No. AST–1747658.

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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