Central Bureau for Astronomical Telegrams
IAUC 5262: N Her 1991; N Cen 1991
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Circular No. 5262
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
M. Dopita, S. Ryder, and E. Vassiliadis report: "We have
observed Nova Her 1991 on Apr. 8.8 and May 6.7 UT using the Double
Beam Spectrograph on the 2.3-m telescope operated by the Mount
Stromlo and Siding Spring Observatories of the Australian National
University. These show that the nova is a member of the O/Ne class
of objects, and has fairly low reddening. The earlier observation
shows the [Ne III] 386.8-nm line present at about twice the strength
of H-beta, and [Ne V] 342.6-nm emission present at about one-third
the strength of the [Ne III] line. He II 468.6-nm emission was
present at about one-half the intensity of H-beta. In the later
spectrum, the [Ne V] emission was as strong as the [Ne III]
emission, and both were about 5 times the strength of H-beta. The
He II/H-beta ratio was 1.6. These spectra appear very similar to
Nova LMC 1990-1."
T. Kato and R. Hirata, Department of Astronomy, Kyoto University,
report that CCD photometry with the 0.60-m reflector at Ouda
station revealed 4 distinct eclipse-like fadings (amplitude 0.3 in
V, duration 1.5 hr). The minima at Apr. 22.727, 27.785, May 3.738,
and 4.631 UT are well represented by a period of 0.2976 day.
NOVA CENTAURI 1991
F. Jablonski and J. Braga, Astrophysics Division, Instituto de
Pesquisas Espaciais/SECT, Sao Jose dos Campos, report: "We have
obtained CCD coude spectra (resolution about 10 000) of Nova Cen 1991
at 656 and 590 nm at CNPq/Laboratorio Nacional de Astrofisica on
Apr. 25. H-alpha has an asymmetric profile with an absorption feature
centered at -450 km/s. The profile has FWHM = 700 km/s, FWZI =
4500 km/s, and total equivalent width (EW) = 18 nm. The resonant
doublet of Na I at 590 and 596 nm has three well defined systems;
the interstellar one is centered at -5 km/s and has EW = 0.036 (D1)
and 0.043 nm (D2), and the shell systems have velocities of -420 and
-650 km/s, respectively. All three systems are superimposed on a
broad emission feature at about 590 nm. No He I emission is seen at
587.6 nm. All velocities are heliocentric."
Photometry by A. C. Gilmore with the 0.6-m Cassegrain reflector
at Mount John University Observatory (cf. IAUC 5250): Apr. 30.53 UT,
V = 10.27 +/- 0.01, U-B = +0.56 +/- 0.04, B-V = +1.67 +/- 0.02, V-R
= +1.17 +/- 0.01, V-I = +2.27 +/- 0.01; May 1.60, 10.24 +/- 0.02,
+0.44 +/- 0.04, +1.67 +/- 0.01, +1.21 +/- 0.01, +2.41 +/- 0.02.
1991 May 10 (5262) Daniel W. E. Green
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