USNO-B1.0 0564-00551957 , the SIMBAD biblio

2010A&A...510A..59N - Astronomy and Astrophysics, volume 510, A59-59 (2010/2-1)

Hot and cool: two emission-line stars with constrasting behaviours in the same XMM-Newton field.


Abstract (from CDS):

High-energy emissions are good indicators of peculiar behaviours in stars. We have therefore obtained an XMM-Newton observation of HD155806 and 1RXSJ171502.4-333344, and derived their spectral properties for the first time. The X-ray spectrum of HD155806 appears soft, even slightly softer than usual for O-type stars (as shown by a comparison with the O9 star HD155889 in the same XMM-Newton field). It is well-fitted with a two-component thermal model with low temperatures (0.2 and 0.6keV), and it shows no overluminosity (log[LX/LBOL]=-6.75). The high-resolution spectrum, though noisy, reveals a few broad, symmetric X-ray lines (FWHM∼2500km/s). The X-ray emission is compatible with the wind-shock model and therefore appears unaffected by the putative dense equatorial regions at the origin of the Oe classification. 1RXSJ171502.4-333344 is a nearby flaring source of moderate X-ray luminosity (log[LX/LBOL]=-3), with a soft thermal spectrum composed of narrow lines and presenting a larger abundance of elements (e.g. Ne) with a high first ionization potential (FIP) compared to lower-FIP elements. All the evidence indicates a coronal origin for the X-ray emission, in agreement with the dMe classification of this source.

Abstract Copyright:

Journal keyword(s): X-rays: stars - stars: early-type - stars: individual: 1RXSJ171502.4-333344 - stars: individual: HD155806 - stars: emission-line, Be - X-rays: individual: HD155889

Simbad objects: 16

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