Towards accurate cross-calibration of Hinode XRT with other X-ray observatories: tentative detection of the F star HD199143 with XRT

Despite decades of X-ray observations of both solar and stellar coronae with various instruments, placing solar X-ray emission levels in a broader astrophysical context is on surprisingly shaky ground. This is largely due to cross-calibration problems and the difficulty of observing the same targets with both solar and stellar instruments. Here we report on a new attempt at direct cross-calibration between solar and stellar missions: observations by the Hinode X-ray Telescope (XRT) of a young X-ray active F star, HD199143. This star has been previously studied by ROSAT and Chandra, and is eclipsed by the Sun every January. We observed the star for a total of 12.6 hours on ingress and egress, and tentatively detect the source at an emission level broadly consistent with expectations based on the most up-to-date calibrations of Hinode, Chandra, and ROSAT count rates for this star. We discuss further observational and analysis plans.