The classical Blandford & Payne model for the magneto‐centrifugal acceleration and collimation of a disc‐wind is revisited and refined. In the original model, the gas is cold and the solution is everywhere subfast magnetosonic. In the present model the plasma has a finite temperature and the self‐consistent solution of the MHD equations starts with a subslow magnetosonic speed which subsequently crosses all critical points, at the slow magnetosonic, Alfvén and fast magnetosonic separatrix surfaces. The superfast magnetosonic solution thus satisfies MHD causality. Downstream of the fast magnetosonic critical point the poloidal streamlines overfocus towards the axis and the solution is terminated. The validity of the model to disc winds associated with young stellar objects is briefly discussed.

Abstract. We report timing and spectral results for PSR B1509−58 observed by BeppoSAX in February 1998. We obtained pulse profiles with high statistical significance from 0.1 to 300 keV that exhibit the well-known broad asymmetric single pulse. The shape of this pulse does not change across this energy window and can be described as the sum of a narrow and a broader Gaussian component separated ∼0.13 in phase. The spectral distribution can be accurately represented, over the entire BeppoSAX energy range, by a curved function rather than a simple power-law shape. The extrapolation of this model to higher energies is also consistent with the COMPTEL fluxes in the 0.75-30 MeV range, with the maximum luminosity for the broad pulse of PSR B1509−58 reached at ∼5.4 MeV. The comparison with the Crab pulsar spectrum suggests a possible origin of the X-ray emission in terms of synchrotron radiation from secondary pair particles near the neutron star.

We present BeppoSAX observations of Nova Velorum 1999 (V382 Vel), carried out in a broad X‐ray band covering 0.1–300 keV only 15 d after the discovery and again after 6 months. The nova was detected at day 15 with the BeppoSAX instruments which measured a flux Fx≃1.8×10−11 erg cm−2 s−1 in the 0.1–10 keV range and a 2σ upper limit Fx<6.7×10−12 erg cm−2 s−1 in the 15–60 keV range. We attribute the emission to shocked nebular ejecta at a plasma temperature kT≃6 keV. At six months no bright component emerged in the 15–60 keV range, but a bright central supersoft X‐ray source appeared. The hot nebular component previously detected had cooled to a plasma temperature kT<1 keV. There was strong intrinsic absorption of the ejecta in the first observation and not in the second, because the column density of neutral hydrogen decreased from N(H)≃1.7×1023 to N(H)≃1021 cm−2 (close to the interstellar value). The unabsorbed X‐ray flux also decreased from Fx=4.3×10−11 to Fx≃10−12 erg cm−2 s−1.

Nova Velorum 1999 (V382 Vel) was observed by BeppoSAX six months after optical maximum, and was detected as a bright X‐ray supersoft source, with a count rate 3.454±0.002 ct s‐1 in the Low‐Energy Concentrator Spectrometer (LECS). It was the softest and most luminous supersoft source observed with this instrument. The flux in the 0.1–0.7 keV range was not constant during the observation. It dropped by a factor of 2 in less than 1.5 hr and then was faint for at least 15 min, without significant spectral changes. The observed spectrum is not well‐fitted with atmospheric models of a hot, hydrogen burning white dwarf. This is due mainly to a supersoft excess in the range of 0.1–0.2 keV, but the fit can be significantly improved at higher energy if at least one emission feature is superimposed. We suggest that a ‘pseudocontinuum’ was detected, consisting of emission lines in the supersoft X‐ray range superimposed on the thermal continuum of a white dwarf atmosphere. As a result, an accurate determination of the effective temperature and gravity of the white dwarf at this post‐outburst stage is not possible.