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IAUC 4049: 1985G; 1985F; RS Oph; 1984s

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                                                  Circular No. 4049
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM    Telephone 617-495-7244/7440/7444

     H. Kozai, Tokyo Astronomical Observatory, telexes that Shigo
Horiguchi, Tokorozawa, Saitama, has discovered an apparent supernova
2" west and 5" north of the center of NGC 4451. From a photograph
on Tri-X emulsion taken on Mar. 21.631 UT  (mv = 14.5), Kozai
measured the object's position: R.A. = 12h26m09s47, Decl. = +9deg34'32"0,
equinox 1950.0.   On Mar. 24.59, the object was at mv ~ 15.0, while
it was fainter than mag 17 on Feb. 22.666.

     W. Wenzel, Sonneberg Observatory, communicates that observations
made by Huth and Fuhrmann (15 patrol plates between 1984 Feb.
28 and May 1, on Nov. 30.2, and on Dec. 25.1; and 8 plates taken
during 1985 Jan. and Feb.) show no conspicuous object brighter than
mag 12.5 in the location of supernova 1985F (cf. IAUC 4042, 4048).

     Corrigendum.  On IAUC 4048, line 3 under the item for this
object, for  Mar. 17  read  Mar. 18.

     F. A. Cordova, Los Alamos National Laboratory; K. O. Mason,
Mullard Space Science Laboratory; M. F. Bode, Manchester University;
and P. Barr, EXOSAT Observatory, telex: "We have detected
intense x-ray emission from RS Oph using the EXOSAT Observatory.
This symbiotic nova is now declining from an outburst that commenced
on Jan. 26 (IAUC 4030, 4031, 4036).  EXOSAT observed RS Oph
between 18h00 and 23h00 UT on Mar. 22.  Preliminary analysis
indicates that the x-ray spectrum is soft and absorbed.  Fits to a
thermal bremsstrahlung model yield a temperature of 0.75 keV and an
absorbing column density of ~ 10**21 atoms cm**-2.  The flux at Earth
in the 0.1-6.0-keV band is estimated to be 4 x 10**-10 erg cm-**2 s**-1.
Further EXOSAT observations are planned to monitor the decline of
the outburst."

     Visual magnitude estimate by J. E. Bortle, Stormville, NY:
Mar. 16.416 UT, 9.6.

     Total visual magnitude estimate:  Mar. 24.47 UT, 12.0 (C. S.
Morris, Lockwood Valley, CA, 0.25-m reflector).

1985 March 28                  (4049)            Daniel W. E. Green

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