2004A&A...417..667N -
Astronomy and Astrophysics, volume 417, 667-677 (2004/4-2)
HD 108: The mystery deepens with XMM-Newton observations.
NAZE Y., RAUW G., VREUX J.-M. and DE BECKER M.
Abstract (from CDS):
In 2001, using a large spectroscopic dataset from an extensive monitoring campaign, we discovered that the peculiar Of star HD 108 displayed extreme line variations. This strange behaviour could be attributed to a variety of models, and an investigation of the high energy properties of HD 108 was needed to test the predictions from these models. Our dedicated XMM-Newton observation of HD 108 shows that its spectrum is well represented by a two temperature thermal plasma model with kT1∼0.2keV and kT2∼1.4keV. In addition, we find that the star does not display any significant short-term changes during the XMM-Newton exposure. Compared to previous Einstein and ROSAT detections, it also appears that HD 108 does not present long-term flux variations either. While the line variations continue to modify HD 108's spectrum in the optical domain, the X-ray emission of the star appears thus surprisingly stable: no simple model is for the moment able to explain such an unexpected behaviour. Thanks to its high sensitivity, the XMM-Newton observatory has also enabled the serendipitous discovery of 57 new X-ray sources in the field of HD 108. Their properties are also discussed in this paper.
Abstract Copyright:
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Journal keyword(s):
stars: early-type - X-rays: stars - stars: winds, outflows - stars: individual: HD 108
CDS comments:
Table 3: Numbering NN in the first column is not used in SIMBAD,
Simbad objects:
70
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