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IAUC 4610: N LMC; N Her 1987; T Leo

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                                                  Circular No. 4610
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

     G. Sonneborn, IUE Observatory, NASA Goddard Space Flight Center;
S. Starrfield, Arizona State University and Los Alamos National
Laboratory; and W. Sparks, Los Alamos National Laboratory, report:
"Ultraviolet spectra (115-340 nm) obtained with the IUE satellite show
that the nova ejecta have recently entered the nebular phase.  The
ultraviolet continuum is now very weak (cf. IAUC 4588), and the
spectrum below 200 nm is dominated by emission lines spanning a wide
range of ionization potential.  An IUE SWP spectrum was obtained on
May 28.9 UT in which we identify C III 117.5 nm, N V 124.0, O I 130.6,
C II 133.5, Si IV 140.6, N IV] 148.6, C IV 155.0, He II 164.0, O III]
166.3, N IV 171.8, N III] 175.0 and C III] 190.9.  The strongest line
is O I 130.6 nm.  There is a suggestion of an ionization-dependent
shift of the line peaks, where the highest ionization states are
redshifted by 0.2-0.5 nm.  The line wings extend to +/- 2500 km/s.
There has been a definite change in the appearance of the spectrum
from one obtained on May 15.7 UT.  Many of the above lines could not
definitely be identified in the earlier spectrum due to blending with
the continuum.  Many of the stronger lines have also decreased in
strength by about 50 percent.  At the same time the C III and C IV
lines have increased.  An LWP spectrum (200-340 nm) obtained on May
15.8 shows strong lines of O [III]+C II] 232.2-232.8 nm, Mg II 280.0 and
He II 214.8, 230.6 and 320.3, as well as a probable detection of Ne [III]
334.3 nm at the long wavelength cutoff of the camera.  The Ne [III] line
should be detectable in the optical, and we urge confirming observations."

     Visual magnitude estimates: Mar. 20.15 UT, 13.5 (A. Boattini,
Florence, Italy); 23.14, 14.4 (Boattini); May 21.02, 14.6 (M.
Verdenet, Bourbon-Lancy, France); 22.01, 14.6 (Verdenet); June 10.94,
14.4 (Boattini).

     Visual magnitude estimates: May 28.08 UT, 10.7 (P. Dombrowski,
Glastonbury, CT); 30.07, 10.4 (G. Dyck, North Dartmouth, MA); 31.07,
10.5 (Dyck); June 1.07, 10.7 (Dyck); 1.91, 12.3 (P. Schmeer,
Bischmisheim, West Germany); 2.87, 11.6 (Boattini); 4.91, [13.0 (Schmeer).

1988 June 11                   (4610)              Brian G. Marsden

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