학술논문

Chandra HETG X-Ray Spectra and Variability of π Aqr, a γ Cas-type Be Star
Document Type
article
Source
The Astrophysical Journal Letters, Vol 966, Iss 2, p L23 (2024)
Subject
X-ray astronomy
Gamma Cassiopeiae stars
High resolution spectroscopy
Early-type emission stars
White dwarf stars
Be stars
Astrophysics
QB460-466
Language
English
ISSN
2041-8213
2041-8205
Abstract
High-resolution X-ray spectra of π Aqr, a γ Cas-type star, obtained with the Chandra/HETG spectrometer, revealed emission lines of H-like ions of Mg, Si, S, and Fe; a strong, hard continuum; and a lack of He-like ions, indicating the presence of very hot thermal plasma. The X-ray light curve showed significant fluctuations, with coherent variability at a period of about 3400 s in one observation. The hardness ratio was relatively constant except for one observation in which the spectrum was much harder and more absorbed. We interpret the X-ray emission as arising from accretion onto the secondary, which is likely a magnetic white dwarf, an intermediate polar system.