Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6376: 1996V; C/1995 O1; GRO J1744-28

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6375  SEARCH Read IAUC 6377

View IAUC 6376 in .dvi or .ps format.
IAUC number

                                                  Circular No. 6376
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

     Jean Mueller reports her discovery of a supernova on a IV-N
plate taken on Mar. 28 UT by K. M. Rykoski and Mueller with the
1.2-m Oschin Schmidt telescope in the course of the second Palomar
Sky Survy.  SN 1996V (red mag about 16.5 on Apr. 10) is offset 25"
west and 5" north of the center of NGC 3644 (R.A. = 11h21m.5, Decl.
= +2o49', equinox 2000.0).  SN 1996V is not present on a plate
taken on 1991 Jan. 15 by C. Brewer and J.~D. Mendenhall.  An
echelle spectrogram (range 400-540 nm, resolution 0.7 nm) taken on
Apr. 10 at the Palomar 1.5-m telescope by M. Malkan and H. Teplitz
shows broad ripples in the spectrum, including prominent peaks at
471, 502, and 535 nm, consistent with a supernova identification.

     H. A. Weaver, Applied Research Corporation; P. D. Feldman,
Johns Hopkins University; M. F. A'Hearn, University of Maryland; C.
Arpigny, University of Liege; and J. C. Brandt and C. E. Randall,
University of Colorado, write:  "During HST spectroscopic
observations on Apr. 7 (r = 4.8 AU), we clearly detected OH
emission in the A-X (0,0) band near 309 nm with a brightness of
about 25 rayleighs in an aperture of 1".29 x 3".66.  Assuming that
the observed OH was produced during the photolysis of water that
sublimed from the nucleus, we derive a water-production rate of 1.5
x 10E28 molecules/s.  This latter value is only slightly below the
CO-production rates derived from submillimeter observations,
indicating that water sublimation may soon take over as the primary
source of activity in the comet.  For a nonrotating spherical
nucleus at the comet's heliocentric distance, we estimate that the
maximum sublimation rate cannot exceed the subsolar value of about
9 x 10E15 molecules cmE-2 sE-1, which implies (assuming negligible
emission from the nightside) a lower limit of 10 km for the
effective diameter.  If the observed OH is actually due to
sublimation of water from icy grains in the coma, then the latter
conclusion is no longer valid."

GRO J1744-28
     The astrometric investigation by Morrison and Roser on IAUC
6375 was carried out in the absence of their knowledge of IAUC
6369, on which it was shown that the true GRO J1744-28 is located
1'.5 from the candidates that were previously being considered.

                      (C) Copyright 1996 CBAT
1996 April 10                  (6376)            Daniel W. E. Green

Read IAUC 6375  SEARCH Read IAUC 6377

View IAUC 6376 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!