Icy celestial bodies on highly eccentric orbits that pass close to the star they Orbit will have their surface evaporate at they approach and depart their periapsis. These leaves trails of ice crystals and gasses that can stretch for hundreds of thousands of kilometers or more. ??
Adding a comet trail to Handrew's Comet would make it 1) more realistic and 2) sick as frick. You'd be able to see the comet from Droo which would also make telescopes more fun to build
Edit: Title should say trail