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IAUC 2911: X-RAY BURSTS FROM NEAR THE GALACTIC CENTER; VY CMa; P/JOHNSON; simga Ori E; NOTICE TO Tlgm SUBSCRIBERS
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Circular No. 2911
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS
X-RAY BURSTS FROM NEAR THE GALACTIC CENTER
W. H. G. Lewin, Massachusetts Institute of Technology, reports
that the SAS-3 Group has observed two extremel strong x-ray bursts
from the vicinity of the galactic center: R.A. = 17h43m, Decl. = -29o.2
(l = -0o.2, b = -0o.2), with an error circle of radius 0o.4. The bursts,
which had their onset on Feb. 7.90659 and 9.27241 UT, have a low-energy
cut-off near 2.5 keV. At high energies (8-18 keV) they show
two peaks with width (FWHM) ~ 2s and ~ 4s, separated by about 9s.
In the energy ranges 2.5-5 and 5-10 keV the maximum intensity is
comparable to that of the Crab Nebula. Observers are urged to
search for this phenomenon at other frequencies.
VY CANIS MAJORIS
I. S. Glass, South African Astronomical Observatory, reports
that infrared photometry by Robertson, Stewart, Williams and himself
during Jan. 22-28 gave H = +0.43, K = -0.79, L = -2.59.
PERIODIC COMET JOHNSON
The following prediction has been derived by S. W. Milbourn
and the late G. Lea, British Astronomical Association, from the
predicted elements for the 1970 return given in the Catalogue of
Cometary Orbits. Perturbations by the planets Venus to Neptune
were taken into account. There is a similar prediction by R. Luss
in Handb. Br. Astron. Assoc. for 1976.
T = 1977 Jan. 8.4603 ET Epoch = 1977 Jan. 17.0 ET
Peri. = 206.2124 e = 0.386067
Node = 117.7956 1950.0 a = 3.576391 AU
Incl. = 13.9067 n = 0.1457258
q = 2.195663 AU P = 6.763 years
For dT = +1d
1976 ET R. A. (1950) Decl. Delta r dR.A. dDecl. m2
Mar. 3 17 05.84 -10 09.2 2.907 3.004 -0m82 + 3'4 21.0
13 17 14.94 - 9 57.9 -0.88 + 3.6
23 17 22.65 - 9 41.7 2.566 2.928 -0.95 + 3.8 20.5
Apr. 2 17 28.71 - 9 21.9 -1.03 + 4.0
12 17 32.85 - 9 00.2 2.244 2.853 -1.11 + 4.2 20.1
22 17 34.86 - 8 38.8 -1.20 + 4.4
May 2 17 34.53 - 8 20.1 1.966 2.778 -1.28 + 4.7 19.6
12 17 31.80 - 8 07.2 -1.37 + 4.9
22 17 26.83 - 8 03.1 1.757 2.705 -1.44 + 5.2 19.2
June 1 17 19.96 - 8 10.7 -1.49 + 5.4
11 17 11.90 - 8 32.0 1.639 2.635 -1.51 + 5.6 18.9
21 17 03.55 - 9 07.9 -1.50 + 5.8
July 1 16 55.89 - 9 57.7 1.623 2.566 -1.46 + 6.0 18.7
11 16 49.86 -10 59.8 -1.41 + 6.1
21 16 46.12 -12 11.2 1.697 2.501 -1.34 + 6.1 18.6
31 16 45.08 -13 29.3 -1.28 + 6.2
Aug. 10 16 46.92 -14 51.0 1.835 2.441 -1.22 + 6.1 18.6
20 16 51.58 -16 13.8 -1.17 + 6.0
30 16 58.92 -17 35.4 2.008 2.385 -1.14 + 5.8 18.7
Sept. 9 17 08.76 -18 53.6 -1.11 + 5.6
19 17 20.85 -20 06.6 2.197 2.334 -1.10 + 5.3 18.7
29 17 34.98 -21 12.5 -1.09 + 5.0
Oct. 9 17 50.94 -22 09.8 2.385 2.291 -1.09 + 4.6 18.8
19 18 08.49 -22 57.0 -1.09 + 4.2
29 18 27.44 -23 32.6 2.563 2.255 -1.09 + 3.6 18.8
Nov. 8 18 47.56 -23 55.7 -1.10 + 3.1
18 19 08.64 -24 05.4 2.725 2.227 -1.10 + 2.5 18.9
28 19 30.50 -24 01.1 -1.11 + 1.9
Dec. 8 19 52.90 -23 42.7 2.867 2.207 -1.11 + 1.2 18.9
m2 = 11.5 + 5 log Delta + 15 log r
simga ORIONIS E
J. E. Hesser and P. Ugarte, Cerro Tololo Interamerican Observatory,
write that recent photometry shows eclipse-like variations
with primary minima given by 1976 Jan. 1.31863 + 1.19080 (+/- 0.00005)
E UT; depths are about 0.1 magnitude. Secondary minima follow by
12h.40, and both last about 3h.0 at half depth. Limits on radial-velocity
variations (Bolton 1974, Astrophys. J. 192, L7) suggest
the mass of any companion <~ 0.1 Msol. More radial-velocity observations
and x-ray and radio monitoring of the system would be useful.
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1976 February 12 (2911) Brian G. Marsden
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