’ Her X-1 is
an eclipsing binary system: NS + A/F star.
’ Pspin ~1.24 s , Porbital ~1.7 d
’ X-ray intensity varies on a period of 35 d. ³Main-on² ~ 10 d; ³short-on² ~ 5 d,
separation period ~ 10 d of lower intensity.
’ Main-on
broadband spectrum: bb at ~0.1 keV
+ PL + exponential cut-off at higher
energies. Low NH ~1019 cm-2.
Also: I) a Gaussian feature at ~1
keV; ii) a Fe line at ~6.4 keV; iii) a cyclotron absorption
line at ~40 keV (ÞB ~3 x1012 G) (see e.g. McCray et al. 1982, Oosterbroek et al.1997, Dal Fiume et al. 1997).
’Spectra
taken outside the main-on are fitted by adding one or more partial covering
absorbtion components (NH ~1022-1023 cm-2) to the
model above.