Discussion and graphics from the paper by Vidal-Madjar et al.
Doppler Discovery of the planet orbiting HD 209458.
Predictions of comet tails from hot jupiters have been made by Burrows and Lunine 1995, Schneider et al 1988 and Moutou et al 2001.
References:
Burrows,A. & Lunine,J. 1995, Nature 378, 333
C. Moutou, A. Coustenis, J. Schneider, R. St Gilles, M. Mayor, D. Queloz and A. Kaufer, 2001 Search for spectroscopical signatures of transiting HD 209458b's exosphere. Astron. & Astrophys., 371, 260 http://www.edpsciences.org/articles/aa/abs/2001/19/aa10462/aa10462.html
Schneider, J., Rauer, H., Lasota, J.-P. & Bonazzola, S., 1998 The cometary-like tail of giant extrasolar planets in close orbits. in Proceeding of the "Brown Dwarfs and Extrasolar Planets" Conference, 1997 (Rebolo et al. Eds). ASP Conf. Ser. 134, 241 http://www.obspm.fr/encycl/papers/tenerife.pdf
Cometary tails of close giant planets (picture)
by J. Schneider & Sekulic, June 1999.