Comet 1989m (SMM 8)

O. C. St. Cyr, High Altitude Observatory, reports the discovery by D. L. Kobe and himself of another probable sungrazing comet during routine inspection of the Solar Maximum Mission coronagraph images. As for SMM 5, SMM 6 and SMM 7, measurements of the comet's position were made by A. Stanger, High Altitude Observatory, and the reduction was made by D. Pitone and B. Twambly of the SMM Flight Dynamics Facility at NASA Goddard Space Flight Center. 1989 UT R.A. (1950) Decl. June 2.40347 4 36 22 +21 22.2 2.41528 4 36 22 +21 24.6 2.42083 4 36 22 +21 25.8 2.46806 4 36 34 +21 39.0 2.47917 4 36 36 +21 42.0 2.48472 4 36 38 +21 44.4 SMM8 is a faint object, perhaps comparable to SMM 1 and SMM 3, at about mag 0. The measurements refer to the positions of the 'head', i.e., the sunward end of the bright cometary tail. The radial distance measurements are believed to be accurate to +/- 0.1 solar radius and the p.a. to +/- 1 deg. Another image on June 2.533 UT showed only the comet's tail, as the head disappeared under one of the instrument's electronic artifacts. That was the last detection of the comet, although observations continued until June 2.625 UT. The following parabolic orbital elements, determined by the undersigned on the assumption that the comet has the same perihelion direction as the other Kreutz sungrazers, satisfy the above positions within better than 1': T = 1989 June 2.578 ET, Peri. = 84.72, Node = 5.54, Incl. = 144.63 (equinox 1950.0), q = 0.00557 AU.