[en] In 2007 January, at the heliocentric distance r < 0.3 AU, comet McNaught 2006P1 became the brightest comet since C/Ikeya-Seki 1965S1 and was continuously monitored by space-based solar observatories. We provide strong evidence that an archlike tail observed by the Heliospheric Imager aboard the STEREO spacecraft is the first ever detected tail composed of neutral Fe atoms. We obtain an Fe lifetime tau = (4.1 +/- 0.4) x 10(4) s at r = 0.25 AU, in agreement with theoretical predictions of the photoionization lifetime. The expected dust temperature is inconsistent with iron sublimation, suggesting that Fe atoms are coming from troilite evaporation.
Bockelée-Morvan, D., Crovisier, J., Mumma, M. J., & Weaver, H. A. 2004, in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 391
Burbine, T. H., McCoy, T. J., Nittler, L. R., Benedix, G. K., Cloutis, E. A., & Dickinson, T. L. 2002, Meteoritics Planet. Sci., 37, 1233
Burns, J. A., Lamy, P. L., & Soter, S. 1979, Icarus, 40, 1
Cremonese, G., et al. 1997, ApJ, 490, L199
Crifo, J. F., Fulle, M., Komle, N. I., & Szego, K. 2004, in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 471
Davis, C. J., & Harrison, R. A. 2005, Adv. Space Res., 36, 1524
Feldman, P. D., Cochran, A. L., & Combi, M. R. 2004, in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 425
Finson, M. L., & Probstein, R. F. 1968, ApJ, 154, 327
Fulle, M. 2004, in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 565
Harrison, R. A., Davis, C. J., & Eyles, C. J. 2005, Adv. Space Res., 36, 1512
Huebner, W. F., Keady, J. J., & Lyon, S. P. 1992, Ap&SS, 195, 1
Knacke, O., Kubaschewski, O., & Hesselmann, K. 1991, Thermochemical Properties of Inorganics Substances (New York: Springer)
Kolokolova, L., Hanner, M. S., Levasseur-Regourd, A. C., & Gustafson, B. A. S. 2004, in Comets II, ed. M. C. Festou, H. U. Keller, & H. A. Weaver (Tucson: Univ. Arizona Press), 577
Kurucz, R. L., Furenlid, I., Brault, J., & Testerman, L. 1984, Solar Flux Atlas from 296 to 1300 nm (National Solar Observatory Atlas, No. 1) (Sunspot: NSO)
Morton, D. C. 2003, ApJS, 149, 205
_. 2004, ApJS, 151, 403
Nemiroff, R., & Bonnell, J. 2007, Astronomy Picture of the Day, http://-
antwrp.gsfc.nasa.gov/apod/ap070117.html
Pollack, J. B., Hollenbach, D., Beckwith, S., Simonelli, D. P., Roush, T., & Fong, W. 1994, ApJ, 421, 615
Preston, O. W. 1967, ApJ, 147, 718
Sostero, O. 2007, Cometary Data Archive for Amateur Astronomers, http://cara.uai.it
Sprague, H. A. L., Hunten, D. M., & Lodders, K. 1995, Icarus, 118, 211
Stone, E. C., et al. 1990, in AIP Conf. Proc. 203, Particle Astrophysics: The NASA Cosmic Ray Program for the 1990s and Beyond, ed. M. V. Jones, F. J. Kerr, & J. F. Ormes (New York: AIP), 48
Tedesco, E. F., Tholen, D. J., & Zellner, B. 1982, AJ, 87, 1585
Tokunaga, A., Golish, T., Griep, D., Kaminski, C., & Hanner, M. S. 1988, AJ, 96, 1971
Verner, D. A., Ferland, G. J., Korista, K. T., & Yakovlev, D. G. 1996, ApJ, 465, 487
Wyckoff, S. 1982, in Comets, ed. L. L. Wilkening (Tucson: Univ. Arizona Press), 3
