BeppoSAX LECS detection of comet C/1995 O1(Hale-Bopp)

We report the detection of soft X-rays from comet C/1995 O1 (Hale-Bopp) by the LECS instrument on-board BeppoSAX on 1996 September 10-11. After correcting for the comets motion, a 7σ enhancement was found within 2' of the expected location of the nucleus at much greater than 99.99% confidence. A weak 1.3σ enhancement was also found in MECS data at the same location. The extracted LECS spectrum is well fit by a thermal bremsstrahlung model of temperature of 0.29 ± 0.06 keV - consistent with that observed in other comets. The 0.1-2.0 keV luminosity has a mean value of 5x1016 erg s-1 and is a factor of ∼ 8 greater than measured by the Extreme Ultraviolet Explorer (EUVE) 4 days later. This difference may be related to the emergence from the nucleus on 1996 September 9 of a dust-rich cloud which continued to expand rapidly over the next few days becoming tenuous by the start of the EUVE observation. There is no evidence for fluorescent carbon or oxygen emission with 95% confidence limits of 1.0x1015 and 7.8x1015 erg s-1 to narrow line emission at 0.28 and 0.53 keV, respectively. This implies that if such lines are present, their total luminosity must be must be <18% of the 0.1-2.0 keV continuum luminosity