Circular No. 5418 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Telephone 617-495-7244/7440/7444 (for emergency use only) TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505 MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN S PERSEI D. Crabtree and C. Aikman, Dominion Astrophysical Observatory, communicate: "CCD spectra of the M supergiant S Per obtained with the 1.2-m and 1.8-m DAO telescopes between Nov. 28 and Dec. 14 indicate that this star is currently undergoing a very deep minimum. Spectra with 0.03-nm and 0.18-nm resolution in the 850-nm region show very strong TiO bands and very weak Ca II lines, which indicate a spectral type of M6 or later. A spectrum in the 770-nm region (resolution 0.08 nm) shows a strong emission reversal in the K I line at 769.8 nm. There is no evidence for H alpha emission in a spectrum with 0.03-nm resolution. Further observations of this star, including photometry and monitoring of the H2O and OH maser emission, are encouraged." 1991 XB Precise positions measured by J. V. Scotti from images obtained by D. Rabinowitz with the Spacewatch camera at Kitt Peak: 1991 UT R.A. (2000) Decl. V Dec. 13.34496 4 07 30.84 +13 22 55.6 17.7 13.35222 4 07 31.61 +13 22 32.5 17.7 15.10460 4 11 08.55 +11 52 14.2 17.9 15.11149 4 11 09.34 +11 51 53.5 Orbital elements from 10 observations Dec. 1-15: T = 1991 Nov. 26.7998 TT Peri. = 171.6570 e = 0.581430 Node = 250.7720 2000.0 q = 1.250397 AU Incl. = 16.0978 a = 2.987310 AU n = 0.1908902 P = 5.163 years 1991/92 R. A. (2000) Decl. Delta r Elong. Phase V Dec. 20 4 20.75 + 8 06.2 0.321 1.279 153.7 19.9 17.6 30 4 39.05 + 2 25.1 0.375 1.309 145.2 25.4 18.1 Jan. 9 4 56.18 - 0 53.2 0.443 1.347 138.4 29.0 18.7 19 5 12.92 - 2 27.3 0.523 1.393 132.8 31.2 19.1 29 5 29.65 - 2 52.9 0.614 1.445 127.9 32.5 19.6 Feb. 8 5 46.65 - 2 36.4 0.714 1.503 123.3 33.3 20.0 1991 December 27 Brian G. Marsden