Circular No. 2823 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Cable Address: SATELLITES, NEWYORK Western Union: RAPID SATELLITE CAMBMASS A0620-00 W. Liller, Center for Astrophysics, reports: "Lola J. Eachus has discovered on Harvard plates that the star associated with A0620-00 (see IAUC 2819) also erupted in 1917, reaching B = 12.0 or slightly brighter in early November. The star is seen on five blue-sensitive plates, and the shape of its light curve is well enough determined to show that it is nova-like in appearance. The star remained brighter than B = 13.0, the limiting magnitude of the patrol plates, for 75 to 150 days. From our magnitude estimate for this star on the blue Palomar Sky Survey print, B ~ 20, we deduce a range of about 8 magnitudes, typical of recurrent novae with similar time intervals between outbursts (57.8 years for A0620-00). According to C. Payne-Gaposchkin (1962, 'The Galactic Novae', New York: Dover), the absolute magnitude of recurrent novae at maximum is M_B ~ -7.5, and if the interstellar absorption amounts to 1.0 mag/kpc, then the distance to A0620-00 is 5700 pc." K. Locher, Grut-Wetzikon, Switzerland, sends the following visual magnitude estimate: Aug. 21.14 UT, 10.4. There was probably no fluctuation exceeding 0.2 magnitude within 30 min. Comparison was made with the AAVSO sequence for V Mon. F. Owen, National Radio Astronomy Observatory; T. Balonek, University of Massachusetts; J. Dickey and Y. Terzian, Cornell University; and S. Gottesman, University of Florida, report that observations made with the N.R.A.O. 91-m telescope and the Green Bank interferometer indicate that the flux of the radio source associated with A0620-00 has decayed. Preliminary results are as follows: 1975 UT Frequency Flux density Telescope Aug. 15.59 1400 MHz 0.30 +/- 0.08 Jy 91-m 16.59 2695 0.26 +/- 0.04 " 18.58 2695 0.14 +/- 0.03 " 18.6 1418 0.13 +/- 0.06 interferometer 20.57 2695 0.11 +/- 0.025 91-m 22.4 1420 0.05 +/- 0.01 interferometer P. F. Scott, Mullard Radio Astronomy Observatory, reports that the right ascension of the radio source is R.A. = 6h20m11s.256 +/- 0s.010 (equinox 1950.0). On Aug. 22 the flux density at 5000 MHz was 0.02 +/- 0.007 Jy. 1975 August 27 (2823) Brian G. Marsden
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