Central Bureau for Astronomical Telegrams
IAUC 3882: 4U 1907+09; 4U 1755-33; 1983 RD
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Circular No. 3882
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
4U 1907+09
Y. Tanaka and the Tenma Team telex: "4U 1907+09 was observed
with the x-ray satellite Tenma during Aug. 29-Sept. 7, covering
one complete binary 8.4-day period (Marshall and Ricketts 1980,
MNRAS 193, 7P). A clear x-ray pulsation, of period ~ 438 s, was
detected throughout the observation. A preliminary timing analysis
shows that the Doppler delay is consistent with an orbit of
8.4-day period, e = 0.2 and a sin i = 105. Periastron passage
occurred on 1983 Sept. 1.8 UT, and the heliocentric pulse period
is 437.463 +/- 0.003 s. The preliminary mass function, 18 +/- 4 MO,
confirms the massive nature of the primary (Schwartz et al. 1980,
A.J. 85, 549). Further optical observations are encouraged."
4U 1755-33
N. E. White and A. N. Parmar, European Space Agency; and
K. O. Mason, Mullard Space Science Laboratory, report that a
9.7-hr GSPC ESOSAT observation on Aug. 7 revealed three ~ 30-min
dips equally separated by 4.4 +/- 0.2 hr. With considerable
variability and no obvious energy dependence, the flux was reduced by ~
20 percent during each event. The events are reminiscent of the
50-min absorption dips seen from 4U 1916-05 (cf., e.g., White and
Swank 1982, Ap.J. 253, L61). 4U 1755-33 is one of several x-ray
sources that have unusually soft spectra when compared to the vast
majority of galactic sources (IAUC 3806). Observations of the
mag-19 optical counterpart are urged.
1983 RD
Ephemeris continuation from MPC 8214:
1983/84 ET R.A. (1950.0) Decl. p r Mag.
Nov. 2 4 55.41 -18 31.5 0.223 1.149 16.0
12 4 53.88 -17 41.5
22 4 48.55 -15 46.9 0.310 1.244 16.6
Dec. 2 4 42.31 -13 01.9
12 4 37.37 - 9 43.4 0.428 1.361 17.4
22 4 35.13 - 6 10.6
Jan. 1 4 36.02 - 2 40.1 0.595 1.490 18.3
11 4 40.06 + 0 38.1
21 4 46.95 + 3 38.0 0.815 1.622 19.3
1983 October 25 (3882) Brian G. Marsden
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