Central Bureau for Astronomical Telegrams
IAUC 5226: N Her 1991; DX And; 1990c
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Read IAUC 5227
Circular No. 5226
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
NOVA HERCULIS 1991
G. Sonneborn, Goddard Space Flight Center, NASA; S. Shore,
Computer Sciences Corporation and Goddard High Resolution Spectrograph;
and S. Starrfield, Arizona State University, report: "Low-dispersion
spectra (115.0-330.0 nm, resolution 0.6 nm) of Nova Her 1991 were
obtained with the International Ultraviolet Explorer satellite on
Mar. 25.8, 27.0, and 28.8 UT. The ultraviolet spectrum on Mar. 25.8
showed a continuum sharply attenuated shortward of 170 nm by absorption
from an optically thick shell. The absorption is not as severe
as is typically seen in the earliest ultraviolet spectra of classical
novae. Mg II was in emission, with FWHM = 3300 km/s and FWZI =
7300 km/s. No other prominent single emission lines were present in
the early spectrum. Spectra taken on Mar. 27.0 showed weakening of
the region longward of 270 nm by a factor of about 2, and an
increase in flux shortward of 160 nm by about 60 percent as compared
with the earlier spectrum. Integrated ultraviolet fluxes (120-320
nm) in units of erg cmE-2 sE-1 were 4.7 x 10E-9 on Mar. 25.8 and 3.1
x 10E-9 on Mar. 27.0. The quick-look spectrum from Mar. 28.8
appears to show N V 124-nm and strong, sharp emission lines with a
weaker overall continuum. Visual magnitude estimates from Fine Error
Sensor measurements are: Mar. 25.8, 7.1; 27.0, 8.0; 28.8, 8.4.
Ultraviolet observations are continuing. Optical spectra are
urgently needed for reddening determinations and velocities."
Further magnitude estimates, visual unless noted otherwise (cf.
IAUC 5224): Mar. 23.77 UT, [10 (M. Yamamoto, Okazaki, Japan,
photographic); 28.10, 7.8 (P. Schmeer, Bischmisheim, Germany); 28.5, 8.0
(R. Royer, Lakewood, CA); 29.5, 8.3 (Royer).
DX ANDROMEDAE
This cataclysmic variable is again in outburst (cf. IAUC 4914),
as indicated by the following visual magnitude estimates: Mar.
25.28 UT, 11.5 (T. Kinnunen, Finland; communicated by G. M. Hurst,
Basingstoke, England); 28.17, 11.8 (P. Schmeer, Bischmisheim, Germany).
COMET LEVY (1990c)
Total visual magnitude estimates by A. Hale, Las Cruces, NM:
Mar. 13.26 UT, 9.2 (10x50 binoculars); 17.28, 9.2 (0.41-m reflector).
1991 March 29 (5226) Daniel W. E. Green
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