Comet P/2008 X4 = P/2003 K2 (Christensen)

K. Battams, Naval Research Laboratory, writes that A. Watson found a comet on SECCHI HI1-B images (via the STEREO-B spacecraft; cf. IAUC 8926, 8930), Battams noting a very faint, short tail ("discovery" observation tabulated below). R. Kracht made measurements of the object's position and computed a parabolic orbit, from which M. Meyer suggested identity with comet P/2003 K2 (cf. IAUC 8136, 8138, 8145). The indicated correction to the prediction on MPC 56802 is Delta(T) = -22 days. 2008 UT R.A. (2000) Decl. Mag. Dec. 8.239 12 56.2 -17 06 10 Astrometric measurements of P/2008 X4 by Battams, with reductions by B. G. Marsden, are published on MPEC 2008-X81, together with the following orbital elements by Marsden -- linking the two apparitions (from 227 observations; mean residual 2".9) -- and an ephemeris. Epoch = 2003 Mar. 22.0 TT T = 2003 Apr. 7.8452 TT Peri. = 345.4643 e = 0.828360 Node = 93.9292 2000.0 q = 0.548752 AU Incl. = 10.1398 a = 3.197110 AU n = 0.1724121 P = 5.72 years Epoch = 2008 Nov. 30.0 TT T = 2008 Dec. 19.9610 TT Peri. = 345.7643 e = 0.831673 Node = 93.8928 2000.0 q = 0.534811 AU Incl. = 10.2156 a = 3.177213 AU n = 0.1740342 P = 5.66 years