Central Bureau for Astronomical Telegrams
IAUC 2939: (944); B2 1308+326; Cir X-1
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Read IAUC 2940
Circular No. 2939
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
(944) HIDALGO
The following prediction, by B. G. Marsden, is based on
observations 1920-1964. The ephemeris, more extensive than that in
Efemeridy Malykh Planet for 1976, is provided principally for those
contemplating making physical observations of this object.
T = 1977 Feb. 18.2202 ET Epoch = 1977 Jan. 17.0
Peri. = 57.3899 e = 0.656554
Node = 20.9637 1950.0 a = 5.863095 AU
Incl. = 42.3957 n = 0.0694246
q = 2.013657 AU P = 14.20 years
1976/77 ET R. A. (1950) Decl. Delta r Ph. Mag.
May 2 0 52.50 -12 48.4 4.046 3.309 10.8 18.0
12 1 03.34 -11 02.5
22 1 14.00 - 9 18.6 3.753 3.185 13.9 17.8
June 1 1 24.40 - 7 36.6
11 1 34.44 - 5 56.3 3.418 3.062 16.9 17.6
21 1 44.03 - 4 17.4
July 1 1 53.03 - 2 39.4 3.052 2.941 19.4 17.3
11 2 01.27 - 1 01.7
21 2 08.55 + 0 36.7 2.669 2.821 21.1 17.0
31 2 14.60 + 2 17.1
Aug. 10 2 19.09 + 4 01.0 2.287 2.703 21.4 16.6
20 2 21.64 + 5 50.7
30 2 21.75 + 7 48.3 1.928 2.590 19.6 16.1
Sept. 9 2 18.91 + 9 56.1
19 2 12.59 +12 15.7 1.621 2.481 14.9 15.5
29 2 02.40 +14 46.5
Oct. 9 1 48.37 +17 25.0 1.406 2.380 7.0 14.8
19 1 31.16 +20 03.6
29 1 12.24 +22 33.0 1.318 2.286 7.3 14.6
Nov. 8 0 53.69 +24 46.1
18 0 37.52 +26 41.4 1.358 2.204 17.0 14.9
28 0 25.22 +28 22.9
Dec. 8 0 17.50 +29 58.0 1.489 2.133 24.1 15.2
18 0 14.36 +31 33.1
28 0 15.57 +33 13.6 1.660 2.077 27.7 15.5
Jan. 7 0 20.70 +35 02.5
17 0 29.37 +37 00.9 1.839 2.038 28.8 15.7
27 0 41.34 +39 08.9
Feb. 6 0 56.44 +41 25.3 2.005 2.017 28.4 15.9
16 1 14.64 +43 47.7
26 1 36.07 +46 13.1 2.156 2.015 27.2 16.0
Mar. 8 2 00.86 +48 37.2
18 2 29.26 +50 54.4 2.294 2.032 25.7 16.1
28 3 01.43 +52 58.6
Apr. 7 3 37.32 +54 42.4 2.428 2.067 24.1 16.2
17 4 16.57 +55 58.2
27 4 58.31 +56 39.7 2.567 2.119 22.3 16.3
May 7 5 41.16 +56 42.9
17 6 23.57 +56 06.9 2.718 2.187 20.3 16.5
27 7 04.15 +54 54.8
June 6 7 41.90 +53 11.8 2.884 2.267 18.1 16.6
16 8 16.41 +51 04.6
26 8 47.65 +48 40.1 3.061 2.358 15.7 16.8
July 6 9 15.85 +46 04.2
16 9 41.37 +43 21.9 3.241 2.458 13.2 16.9
Mag. = 12.0 + 5 log Delta + 5 log r + 0.023 ph.
B2 1308+326
W. Liller, Center for Astrophysics, communicates: "E. W.
Gottlieb has discovered that this BL-Lac object is currently in an
eruptive phase. The object, which was brought to our attention by
H. R. Miller, Georgia State University, appears on the blue Palomar
Sky Survey print at an estimated B ~ 20.0, and on archival Harvard
plates it is usually fainter than B = 17.5. However, in the 1940s
it reached B ~ 14.4; in Apr. 1974 it was seen at B ~ 14.2 and in
Apr. 1975 at B ~ 15.3. Blue plates taken with the 155-cm reflector
on 1976 Apr. 7 and 8 UT show it at B = 16.1 and 16.7, respectively.
B2 1308+326 is one of the most variable BL-Lac objects known, and
spectrographic and radio observations would now be desirable."
CIRCINUS X-1
L. J. Kaluzienski, S. S. Holt, E. A. Boldt and P. J.
Serlemitsos, Goddard Space Flight Center, report: "Analysis of
recent data from Cir X-1 (3U 1516-56) with the Ariel 5 all-sky monitor
indicates the presence of a source modulation of period 16.59 +/-
0.06 days. About ten cycles were observed during Oct. 1975-Mar.
1976, a declining trend over the last few peaks indicating a gradual
return to the low-level emission (< 0.1 times the Crab) that was
characteristic of the source before Oct. 1975. The transition from
highest to lowest emission (a reduction by a factor of >~ 20) within
the 16.59-day period occurs over a timescale of one orbit (<~ 1.5
hours) and may imply an eclipse origin. The epoch of this transition
is 1976 Feb. 2.36 +/- 0.07 UT."
1976 April 12 (2939) Brian G. Marsden
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