  V1298 Tau is a young pre-main sequence star hosting four known exoplanets
that are prime targets for transmission spectroscopy with current-generation
instruments. This work pieces together observations from the NICER X-ray
telescope, the Space Telescope Imaging Spectrograph and Cosmic Origins
Spectrograph instruments aboard Hubble Space Telescope, and empirically
informed models to create a panchromatic spectral energy distribution for V1298
Tau spanning 1 to 100000 Angstroms. We describe the methods and assumptions
used to assemble the panchromatic spectrum and show that despite this star's
brightness, its high-energy spectrum is near the limit of present X-ray and
ultraviolet observatories' abilities to characterize. We conclude by using the
V1298 Tau spectrum as a benchmark for the activity saturation stage of
high-energy radiation from solar-mass stars to compare the lifetime cumulative
high-energy irradiation of the V1298 Tau planets to other planets orbiting
similarly massive stars.
