Was the C14 elevation in 775 CE caused by a Superflare?

The ¹⁴C production of shock-accelerated particles is calculated in terms of the total energy released in energetic particles. The recently reported 1.2% jump in the ¹⁴C content of the atmosphere in the year C.E. 775, it is found, would require more than 10³³ erg in energetic particles, less than first estimates but far more than any known solar flare on record. It is noted that the superflare from a large comet (comparable to C/Hale-Bopp) colliding with the sun could produce shock-accelerated GeV cosmic rays in the solar corona and/or solar wind, and possibly account for the CE 775 event. Such events are in any case inevitable in our solar system. Several additional predictions of cometary encounters with the sun and other stars may be observable in the future.