Central Bureau for Astronomical Telegrams
IAUC 5901: GRO J0422+32; RX J1940.2-1025
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Circular No. 5901
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)
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MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
GRO J0422+32
P. Zhao, P. Callanan, M. Garcia, and J. McClintock, Smithsonian
Astrophysical Observatory, write: "GRO J0422+32, a possible
black hole, is currently undergoing another unexpected and dramatic
outburst. Its optical counterpart has brightened by 4 mag during
the past two weeks at an average rate of 0.3 mag/day. CCD photometry
obtained with the F. L. Whipple Observatory's 1.2-m telescope
gives the following R magnitudes: Nov. 21.52 UT, 19.27 +/- 0.03;
24.21, 19.43 +/- 0.09; 25.72, 19.16 +/- 0.05; 26.19, 18.78 +/-
0.07; Dec. 7.42, 15.45 +/- 0.02; 8.20, 15.50 +/- 0.02; 8.41, 15.38
+/- 0.02. The data from the last two nights indicate that the object
is now probably near its maximum for this outburst event. GRO
J0422+32 was discovered in outburst on 1992 Aug. 5 (IAUC 5580); two
subsequent, short-lived outbursts occurred on 1992 Dec. 20 (IAUC
5685) and 1993 Aug. 12 (IAUC 5842). It is unprecedented for an x-
ray nova to have four outbursts within 16 months. Since the current
outburst may also be short-lived, prompt observations at x-ray
and gamma-ray energies are strongly encouraged."
RX J1940.2-1025
R. Staubert, S. Friedrich, and M. Bassgen, Astronomisches
Institut, Universitat Tubingen; R. K. Sood and S. D. James, Australian
Defence Force Academy; and W. Kollatschny, Universitatssternwarte
Gottingen, report: "We have performed spectroscopic observations
of the newly detected ROSAT source RX J1940.2-1025 near NGC 6814
(IAUC 5850, 5852) on Aug. 8, Sept. 6-7, and Oct. 2 and 26-30. The
spectra show several Balmer and high-excitation He emission lines,
confirming the nature as a cataclysmic variable; we further suggest
that the object is an intermediate polar. The emission lines show
significant wavelength shift with time. Radial velocities determined
from H-alpha are consistent with a sinusoidal modulation, defining
a spectroscopic period of 12120 +/- 3 s (90-percent confidence
for four free parameters) and a half-amplitude of +/- 177
km/s. Heliocentric zero phase is at 1993 Sept. 6.899 UT. We note
that periods determined from x-ray data taken with EXOSAT, Ginga,
and ROSAT are generally longer (by 10-30 s), and so is the photometric
period (12150 s, IAUC 5852). Even though formal uncertainties
in the x-ray periods are sometimes of the same order as the
differences from the spectroscopic period, it is conceivable that
the system shows more than one period."
1993 December 8 (5901) Daniel W. E. Green
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