Central Bureau for Astronomical Telegrams
IAUC 3281: N Cyg 1978; V861 Sco
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Circular No. 3281
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
NOVA CYGNI 1978
T. E. Margrave, University of Montana, communicates the following
preliminary UBV results, obtained with the 40-cm reflector at
the Blue Mountain Observatory: Sept. 19.327 UT, V = 7.44, B-V =
+0.27, U-B = -0.75; 20.296, 7.51, +0.28, -0.68; 24.274, 8.00, +0.31,
-0.72; 27.204, 7.97, +0.34, -0.75; 30.300, 8.32, +0.36, -0.75. Comparison
stars were HR 8272 and SAO 51226, and it is possible that
the above colors are systematically in error. Monitoring of the
nova through the V filter from Sept. 30.330 to 30.380 UT revealed a
repetitive pattern of brightness variations having a period of
0.01 day with a peak-to-peak amplitude of up to 0.065 magnitude,
while the magnitude difference between the two comparison stars remained
constant to within +/- 0.005 over the same time span. Similar
behavior appears to have been present on Sept. 19.36 and 27.24 UT,
but the shorter temporal coverage on those dates precludes any conclusion,
pending further analysis of the observations. The average
brightness decline from discovery to Sept. 19.327 implies Mv approx = -6.7
at maximum, from which one finds a distance of ~ 2 kpc for the nova,
assuming absorption of 1 magnitude per kiloparsec.
Visual magnitude estimates: Oct. 3.14 UT, 8.5 (J. Morgan, Prescott,
AZ); 4.76, 8.8 (S. Baroni and M. Cavagna, Milan, Italy).
V861 SCORPII
E. G. Tanzi, E. A. Treves, P. Salinari and M. Tarenghi, Laboratorio
di Fisica Cosmica and European Southern Observatory, report
the following near-infrared measurements (in Jy) obtained with the
E.S.O. 100-cm photometric telescope. alpha Cen A was the primary reference
(Thomas et al. 1973, Monthly Notices Roy. Astron. Soc. 165, 201)
1978 UT 1.25 um 1.65 um 2.2 um 3.6 um 4.8 um
July 26.08 9.8 +/- 0.3 8.3 +/- 0.3 5.1 +/- 0.2 2.4 +/- 1.7 1.5 +/- 1.0
26.12 9.6 +/- 0.3 8.2 +/- 0.2 4.8 +/- 0.3 2.9 +/- 2.4 1.6 +/- 1.9
26.16 9.3 +/- 0.2 7.6 +/- 0.3 4.8 +/- 0.3 3.2 +/- 1.9 1.4 +/- 3.6
27.1 10.1 +/- 0.2 8.6 +/- 0.2 5.2 +/- 0.1 2.0 +/ -1.0 2.2 +/- 1.0
29.0 10.6 +/- 0.2 7.9 +/- 0.2 5.3 +/- 0.1 2.5 +/ -1.2 1.7 +/- 1.2
30.1 9.2 +/- 0.2 7.2 +/- 0.2 4.4 +/- 0.2 1.9 +/ -1.0 1.2 +/- 1.7
31.1 9.9 +/- 0.2 7.9 +/- 0.2 4.8 +/- 0.3 2.4 +/ -0.8 1.4 +/- 1.4
The data show variability of the source with possible orbital phase
correlation.
1978 October 6 (3281) Brian G. Marsden
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