Extreme Ultraviolet Explorer observations of PSR B0656+14

The pulsar PSR B0656+14 has been observed at γ-ray, X-ray, EUV, and optical energies. These data are consistent with emission originating from a thermal stellar surface augmented by a hot, thermal "polar-cap" and an additional magnetospheric component. We have combined archival Extreme Ultraviolet Explorer (EUVE) and ROSAT data, together with recent analyses of optical photometry, to characterize the surface thermal emission from PSR B0656+14. Because of differences in the EUVE and ROSAT flux for E < 0.18 keV, our combined-data models require a softer surface thermal component at closer distance with a larger intervening column, compared to models using only X-ray data. For a 0.1-2.0 keV source consisting of a dominant soft thermal blackbody that is augmented by both a smaller hot blackbody and a power-law optical component, we derive the source properties at 90% confidence to be T_soft = (4.7-5.5) × 10⁵ K, an absorbing column density of N_H = (1.45-1.65) × 10²⁰ cm^-2, a distance of d/R₁₀ = 135-190 pc, and T_hot = (1.13-1.18) × 10⁶ K.