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arXiv · 1706.05195

pi Aqr is another gamma-Cas object

Yael Naze·Gregor Rauw·Constantin Cazorla
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Abstract

The gamma-Cas category is a subgroup of Be stars displaying a strong, hard, and variable thermal X-ray emission. An XMM-Newton observation of pi Aqr reveals spectral and temporal characteristics that clearly make this Be star another member of the gamma-Cas category. Furthermore, pi Aqr is a binary but, contrary to gamma-Cas, the nature of the companion to the Be star is known; it is a non-degenerate (stellar) object and its small separation from the Be star does not leave much room for a putative compact object close to the Be disk. This renders the accretion scenario difficult to apply in this system, and, hence, this discovery favors a disk-related origin for the gamma-Cas phenomenon.

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Yael Naze, Gregor Rauw, Constantin Cazorla. 2017-06-16. pi Aqr is another gamma-Cas object. https://doi.org/10.1051/0004-6361%2F201731135

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