Central Bureau for Astronomical Telegrams
IAUC 5019: V3890 Sgr
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Read IAUC 5020
Circular No. 5019
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
V3890 SAGITTARII
D. A. H. Buckley, University of Cape Town; and W. F. Wargau
and M. G. Soltynski, University of South Africa, report: "Spectra
(range 400-520 nm, resolution 0.12 nm) taken with the RETICON
detector on the SAAO 1.9-m telescope on May 4.95, 5.96, 6.95-7.19,
and 7.98-8.17 UT show emission lines of the Balmer series, He I,
He II, Fe II, and C III/N III on a fairly flat continuum. These
lines were well fitted by single Gaussians, and the line parameters
obtained from the summed spectra for the strongest lines are
summarized as follows. For H-delta, H-gamma, He II 468.6-nm, and H-
beta, the radial velocities were -33, +58, -86, and +10 km/s on
May 4, and -67, -33, -104, and -53 km/s on May 7-8 (all better than
+/- 10 km/s). The FWHM for these same lines were 640, 830, 590,
and 860 km/s on May 4, and 570, 540, 410, and 620 km/s on May 7-8
(all better than +/- 25 km/s). The equivalent widths for these
lines were 1.1, 1.7, 1.6, and 3.0 nm on May 4, and 2.4, 1.4, 2.5,
and 3.7 nm on May 7 (all better than +/- 0.1 nm). The C III/N III
blend at 464 nm is quite strong and broad in our spectra (EW about
1.6 nm, FWHM about 900 km/s). We note the absence of [O III]
436.3-nm and 495.9- to 500.7-nm lines. Morphologically our spectra
are quite different from those reported by Wagner et al. (IAUC
5006) in that the broad (FWZI about 8600 km/s) component is
considerably weaker, or absent, in our spectra. Neither is there any
evidence of P-Cyg profiles in our spectra. This rapid spectral
evolution is analogous to the early stages of RS Oph's post-outburst
decline. Also noteworthy is the double-peaked structure of He II
468.6-nm, with a red and blue peak separation of 0.25-0.30 nm and a
central depression depth of about 10 percent of the peak line flux.
UBV photometry results from the 1.0-m telescope are as follows:
May 5.03, V = 10.08, B-V = +0.78, U-B = -0.53; May 7.03, 10.38,
+0.84, -0.60; May 8.05, 10.71, +0.91, -0.60."
C.-Y. Shao and M. L. Hazen, Center for Astrophysics, report
the following measurement of the variable star equated with N Sgr
1962 = V3890 Sgr (IBVS 845) from a 0.61-m Bruce refractor plate
taken on 1940 Aug. 8.78 UT: R.A. = 18h27m39s.76 +/- 0s.05, Decl. =
-24 03'15".5 +/- 0".8 (equinox 1950.0). This position agrees with
that found by Belserene (IAUC 5007) for the star that erupted in
1962 to within the error limits, indicating that the 1939-40
brightenings found by Hoffleit are probably from the same object
that later was in outburst as N Sgr 1962.
1990 May 22 (5019) Daniel W. E. Green
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