Circular No. 3480 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758 SUPERNOVA IN MCG -3-34-61 J. Maza, Department of Astronomy, University of Chile, reports the discovery at Cerro El Roble by L. E. Gonzalez and himself of a supernova in the galaxy MCG -3-34-61 (R.A. = 13h19m.2, Decl. = -17o04' equinox 1950.0). On May 18.124 UT the object was of mpg 17, and it is located 37" east and 32" north of the galaxy's nucleus. ABELL 46 H. E. Bond, Department of Physics and Astronomy, Louisiana State University, writes: "The central star of the planetary nebula Abell 46 (R.A. = 18h29m.2, Decl. = +26o53', equinox 1950.0) has been found to be an eclipsing binary with an orbital period of 11h19m. Observations with high-speed photometers and 0.9-m reflectors at Louisiana State University and Kitt Peak National Observatories reveal a primary minimum 48 min in duration and 1.4 mag deep (in the B band) due to a partial eclipse of the hot component of the system. The light curve exhibits a hump 0.5 mag high near orbital phase 0.5, caused by strong heating of one hemisphere of the cool companion. The secondary eclipse is about 0.1 mag deep. Heliocentric times of primary minimum are given by JD 2444350.8214 + 0.47170 E. Aside from the slightly lower inclination, Abell 46 is remarkably similar to UU Sge, the eclipsing nucleus of Abell 63 (Bond, Liller and Mannery 1978, Ap.J. 223, 252). UU Sge and the central star of Abell 46 are now the only two known definite close-binary nuclei of planetary nebulae." (51) NEMAUSA L. K. Kristensen, University of Aarhus; and R. L. Duncombe and P. D. Hemenway, University of Texas, write that this minor planet (B ~ 13) will be located at R.A. =4h47m51s.1, Decl. = +12o44'58" (equinox 1950.0) on 1980 Sept. 17.479 UT and again on 1981 Mar. 18.357 UT. Astrometric observations within + 1 day of these times have potential use in reducing systematic errors in the coordinate system. Observers, particularly those using long-focus instruments, interested in participating in a proposed study should contact Hemenway at Department of Astronomy, University of Texas, Austin, TX 78712, U.S.A. He will coordinate the efforts and is prepared to process any plates that are taken. The minor planet's daily motion will be dRA = +0m.76, dDecl. = -4'.0 in 1980 Sept. and +1m.37, +6'.0 in 1981 Mar. 1980 May 27 (3480) Brian G. Marsden
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