Central Bureau for Astronomical Telegrams
IAUC 2974: Her X-1; UU Sge; Cir X-1; 1975n
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Circular No. 2974
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
HERCULES X-1
P. C. Joss, Massachusetts Institute of Technology, reports
that the SAS-3 Group detected a turn-on in the 35-day cycle of Her
X-1 between July 8.46 and 8.55 UT (orbital phase 0.66-0.72). Of
special interest is the discovery that the soft x-ray flux (0.15-0.75
keV), as well as the flux above 1 kev, increased markedly
within this time interval.
UU SAGITTAE
J. S. Miller, Lick Observatory, reports that observations by
W. Krzeminski and W. Priedhorsky, Mount Wilson Observatory, and
himself show that UU Sge, the variable star whose position coincides
with that of the nucleus of the planetary nebula Abell 63
(Bond 1976, Publ. Astron. Soc. Pacific 88, 192), is an eclipsing
binary with period 11h09m.6; mid-eclipse was observed on June
24d10h17m UT. V = 14.7, B-V = +0.3, U-B = -0.75 were measured for
the combined light of the star out of eclipse and a slightly
fainter star 4" to the east. The eclipse lasts 70 min with a
flat-bottomed minimum of about 16 min. The star is about 4.3 magnitudes
fainter in eclipse. The nebular spectrum is unusual in that the
H Balmer series, O III (5007, 4959 and 4363 A) and He I 5876 A are
the only strong lines. The hot component has an O-type spectrum
with He I 4686 A in absorption. Absence of light flickering, the
depth (and totality) of the eclipse and the appearance of the
nebula make it unlikely that the object is an old nova.
CIRCINUS X-1
I. S. Glass, South African Astronomical Observatory, reports
that infrared observations on July 2-3 of the candidate of Mayo et
al. for Cir X-1 (IAUC 2957) give J = 9.98, H = 8.68, K = 7.67, L =
6.60. These suggest that the object may be symbiotic.
COMET WEST (1975n)
The following precise positions have been reported:
1976 UT R. A. (1950) Decl. Observer
Apr. 22.06007 20 22 48.65 +16 30 14.6 Hopp
May 1.76615 20 06 35.52 +17 29 33.5 Urata
1.76863 20 06 35.19 +17 29 30.9 "
5.71806 19 59 01.69 +17 47 13.8 "
5.72256 19 59 01.21 +17 47 15.3 "
7.38681 19 55 40.30 +17 53 17.4 Harlan
June 5.20865 18 47 20.98 +16 48 52,0 Schwartz
7.45069 18 41 50.14 +16 29 11.9 Giclas
16.24549 18 21 12.59 +14 54 57.0 "
23.22500 18 06 26.66 +13 24 56.4 "
26.12529 18 00 49.70 +12 44 50.2 Schwartz
U. Hopp (Wilhelm Foerster Observatory). 30-cm f/17 refractor.
Measurers: Hopp and U. Surawski. Nucleus A.
T. Urata (JCPM Yakiimo Station). 20-cm f/5.5 reflector. From
Nihondaira Obs. Circ. No. 762. Nucleus A.
E. Harlan (Lick Observatory). Measurer: R. Gilliland. Nucleus A.
G. Schwartz (Harvard College Observatory, Agassiz Station).
Measurers: C. Y. Shao and Z. Sekanina. Nucleus A.
H. L. Giclas (Lowell Obs.). Measurer: M. L. Kantz. Nucleus A.
Further photographic observations of the separations and position
angles of nuclei B and D (relative to nucleus A):
Nucleus B. Mar. 21.12 UT, 18".9, 333o (Surawski); May 7.39, 45".2,
300o (Harlan); June 5.21, 50".3, 296o (Schwartz); 7.45, 46".7, 294o
(Giclas); 16.25, 46".5, 298o (Giclas); 19.27, 44".4, 298o (S.
Murrell and C. Knuckles, New Mexico State University; measured
by E. J. Reese); 23.22, 43".0, 299o (Giclas); 26.13, 41".9, 302o
(Schwartz).
Nucleus D. Mar. 21.12 UT, 9".7, 341o (Surawski); Apr. 22.06, 12".9,
317o (Hopp); May 7.39, 20".8, 310o (Harlan); June 5.21, 22".8, 303o
(Schwartz); 7.45, 22".1, 301o (Giclas); 16.25, 22".1, 299o
(Giclas); 19.27, 21".7, 306o (Murrell et al.); 23.22, 21".2, 305o
(Giclas); 26.13, 21".1, 306o (Schwartz).
Z. Sekanina, Center for Astrophysics, remarks that the earth
will cross the orbit plane of the comet on July 21.26 ET. The
occasion provides a unique opportunity for detecting possible motions
of the nuclei normal to the orbit plane. High-resolution photographs
taken around that time and showing all three nuclei could
lead to the detection of a normal component of the separation
velocity of only 0.1 m/s. A series of exposures between, say, July 18
and 25 would be useful. Long-exposure photographs might also show
emissions of large dust particles concentrated in the orbit plane.
J. Bortle, Brooks Observatory, provides the following visual
magnitude estimates for the condensations (32-cm reflector): June
18.11 UT, A = 14.1, B ~ 15, D = 14.5; 28.13, 14.5, 15.0, 15.0. Total
magnitude estimates, coma diameters and tail information (10 x
50 binoculars): June 21.12, 8.0; 12', elongation in p.a. 270o;
23.14, 8.1, 12', 0o.4 in 263o; 27.13, 8.1, 17', 15' in 280o; 28.13,
8.2, 12', 10' in 280o; July 3.15, 8.3, 10', 12' in 270o; 5.25, 8.3,
11'.5, 20' in 290o; 6.26, 8.3, 10', ~ 12' in 270o.
1976 July 14 (2974) Brian G. Marsden
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