UV-Optical Observations of PSR0656+14 with post-COSTAR HST
Session 21 -- Pulsars
Oral presentation, Monday, 30, 1994, 2:00-3:30

## [21.05] UV-Optical Observations of PSR0656+14 with post-COSTAR HST

France A. Cordova (NASA HQ), Guy S. Stringfellow, and George G. Pavlov (Penn State Univ)

Pulsars emit radiation in many wavebands, including the optical, UV, and X-ray domains. This radiation can arise from both thermal and nonthermal processes, and the relative strengths of their respective contributions depends upon the physical properties of the neutron star magnetosphere and surface atmosphere; e.g., age, magnetic field strength, composition, and (uncertain) interior physics. Soft X-ray detections of a number of pulsars yield temperatures of the order $10^5 - 10^6$K, indicating that pulsars should be UV bright irrespective of the origin of the radiation. We presently have an HST program using the FOC/f96 to detect several pulsars at UV and optical wavelengths. The first pulsar, PSR0656+14, was observed in mid-Feb 1994 and the results will be reported. This is a relatively young pulsar ($\sim 10^5$ yrs) with properties rather similar to Geminga (P=0.385 s, $B \sim 5\times 10^{12} G$) and has an accurate radio position. The soft X-ray spectrum is thermal-like. The HST/FOC observations have sufficient spatial resolution to preclude source-confusion and background contamination, enabling definitive identification and analysis to be performed.