Electronic Telegram No. 3574 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network COMET P/1819 W1 = 2003 WY_25 (BLANPAIN) A new comet discovery reported by Peter Veres, Richard Wainscoat, and Henry Hsieh from three exposures taken with the Pan-STARRS1 telescope at Haleakala on 2013 July 4 (discovery observations tabulated below; first published on MPEC 2013-N20), and posted on the Minor Planet Center's NEOCP, was identified by G. V. Williams as identical with the apparently asteroidal object having the minor-planet designation 2003 WY_25 that was discovered at Catalina a decade ago (discovery observations also tabulated below; first announced on MPEC 2003-W41). Veres et al. noted that the object showed a distinctly non-stellar appearance with a coma extending at least 10" from the nuclear condensation, which itself may have an asymmetric structure with an extension to the southeast on the July 4 images. Follow-up images by Wainscoat and Marco Micheli on July 5.37 UT with the 3.6-m Canada-France- Hawaii Telescope (queue observer David Woodworth) showed a broad 8" tail to the southeast that is rounded and more similar to an asymmetric coma than a proper tail, with a nuclear condensation that appears condensed and quasi- stellar (1".3 FWHM in 0".9 seeing conditions) but off-centered with respect to the broad and almost-spherical extension in five stacked 60-s r-band exposures. After posting on the NEOCP webpage, the object was observed by H. Sato (Tokyo, Japan) on July 5.72 remotely with a 0.51-m f/6.8 astrograph at the iTelescope observatory at Siding Spring, noting a strongly condensed nuclear condensation of V-band magnitude 19.5 inside an outer coma of diameter 17"; follow-up images by Sato on July 6.55 show a strongly condensed coma 30" in diameter with V-band magnitude 17.5 as measured within a circular aperture of radius 16".4 on ten 60-s stacked exposures. 2003 UT R.A. (2000) Decl. Mag. Nov. 22.15395 0 08 44.64 -16 03 51.2 18.1 22.16521 0 08 44.34 -16 03 27.5 18.0 22.17650 0 08 44.02 -16 03 02.9 17.7 22.18779 0 08 43.59 -16 02 39.0 17.9 22.24724 0 08 42.10 -16 00 27.5 18.0 2013 UT R.A. (2000) Decl. Mag. July 4.46054 19 42 54.82 -26 40 10.9 20.1 4.47313 19 42 54.10 -26 40 13.1 20.2 Micheli had noticed in 2003 that 2003 WY_25 was perhaps identical to the long-lost comet D/1819 W1 (Blanpain), and backward integration of the orbit then by B. G. Marsden (cf. IAUC 8485) suggested that the identity could well be correct. S. Nakano, Sumoto, Japan, notes that his prediction (NK 1168) for the forthcoming perihelion passage of 2003 WY_25, assuming identity with P/1819 W1, has Delta(T) = -0.04 day; he adds that the object passed 0.24 AU from Jupiter in July 1995. The following linked orbital elements by Williams are from 275 observations 1819 Dec. 14-2013 July 6 (mean residual 0".77) with assumed non-gravitational parameters A_1 = +0.10 +/- 0.00, A_2 = -0.0054 +/- 0.0001 after Nakano. Additional orbital elements for the unobserved apparitions, residuals, and a current observing ephemeris appear on MPEC 2013-N21. Epoch = 1819 Nov. 22.0 TT T = 1819 Nov. 20.274 TT Peri. = 349.751 e = 0.70249 Node = 79.956 2000.0 q = 0.89056 AU Incl. = 9.227 a = 2.99339 AU n = 0.190309 P = 5.18 years Epoch = 2003 Dec. 27.0 TT T = 2003 Dec. 11.57753 TT Peri. = 9.06939 e = 0.6755768 Node = 69.38276 2000.0 q = 1.0000683 AU Incl. = 5.92915 a = 3.0826045 AU n = 0.18210730 P = 5.41 years Epoch = 2014 Aug. 11.0 TT T = 2014 Aug. 28.20557 TT Peri. = 9.85101 e = 0.6846677 Node = 68.93831 2000.0 q = 0.9608572 AU Incl. = 5.89999 a = 3.0471263 AU n = 0.18529700 P = 5.32 years NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 July 7 (CBET 3574) Daniel W. E. Green