High-resolution data of the peculiar magnetic massive star HD148937 were
obtained with Chandra-HETGS, and are presented here in combination with a
re-analysis of the older XMM-RGS data. The lines of the high-Z elements (Mg,
Si, S) were found to be unshifted and relatively narrow (FWHM of about
800km/s), i.e. narrower than the O line recorded by RGS, which possibly
indicates that the hot plasma is multi-thermal and has several origins. These
data further indicate a main plasma temperature of about 0.6keV and a formation
of the X-ray emission at about one stellar radius above the photosphere. From
the spectral fits and the H-to-He line ratios, the presence of very hot plasma
is however confirmed, though with a smaller relative strength than for the
prototype magnetic oblique rotator θ1\,Ori\,C. Both stars thus share
many similarities, but HD148937 appears less extreme than θ1\,Ori\,C
despite having also a large magnetic confinement parameter.Comment: 13 pages, accepted for publication by Ap