Central Bureau for Astronomical Telegrams
IAUC 3171: 4U 0115+63; Cir X-1; P/SCHWASSMANN-WACHMANN 1; 1977l
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Read IAUC 3172
Circular No. 3171
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 Telex: 921428
Telephone: (617) 864-5758
4U 0115+63
M. Johns, McGraw-Hill Observatory; A. Koski, University of
Michigan; and C. Canizares and J. McClintock, Massachusetts Institute
of Technology, report observations of the brightest star in
the combined SAS-3 and HEAO-1 error boxes for 4U 0115+63 (cf. IAUC
3163). The observations were performed with the McGraw-Hill
Observatory's 130-cm telescope on Kitt Peak. Photoelectric photometry
gives the values V = 15.64, B-V = +1.44, U-B = +0.31 (all +/-
0.05) for Feb. 3.2 UT. A spectrogram obtained with the Mark II
photon-counting spectrometer on Feb. 4.2 shows strong emission at
H-alpha and possible emission at H-beta but no other distinct stellar
features. These characteristics make it nearly certain that the star
is the optical counterpart of the x-ray source. The colors are
consistent with those of an ~ B-type star with Av >~ 5 magnitudes.
S. Rappaport, G. Clark, L. Cominsky and F. Li, Massachusetts
Institute of Technology, report that SAS-3 observations of the x-ray
Doppler curve for the transient source 4U 0115+63 (cf. IAUC
3161) have revealed its binary nature. The orbit of the x-ray star
is moderately eccentric and has a period of 24 days. The measured
mass function of 5 Msol requires that the companion have a mass > 5
Msol. The high optical luminosity likely to be associated with such
a star makes the object with mv ~ 16 in the SAS-3 and HEAO-1 error
boxes (IAUC 3163) the most promising candidate for the optical
counterpart; see also the note by Johns et al. above. Observers
are urged to search for optical variability of this candidate during
x-ray decline and for the binary period.
CIRCINUS X-1
L. J. Kaluzienski and S. S. Holt, Goddard Space Flight Center,
report a continuation of the anomalous behavior (IAUC 3108; Dower
et al. 1977, Bull. Am. Astron. Soc. 9, 644) of Cir X-1 near the
expected time of transition in the 16.6-day cycle (IAUC 3099). In
contrast to the first ~ 2 years of observations of this source
(when no turn-on above a level of ~ 0.1 Crab was observed prior to
phase 0.5), the last three cycles have exhibited increases to the
pretransition flux level within 1 day after turn-off. In particular,
the last two cycles show turn-ons as early as <~ 14h (3-6 keV
flux = 3.0 Crab) and 11h.5 +/- 1h (flux ~ 0.4 Crab) after the predicted
time of transition (Jan. 15.92 and Feb. 1.52 UT, respectively).
PERIODIC COMET SCHWASSMANN-WACHMANN 1
A. Mrkos, Klet Observatory, provides the following precise
positions. From the comet's physical appearance on Jan. 1 as a
diffuse circular coma with a well-defined central condensation and
the fact that the comet was fainter than normal on 1977 Dec. 18 and
19, he suggests that the outburst occurred on Dec. 25 or 26 (cf.
the Japanese observations on IAUC 3165).
1978 UT R. A. (1950) Decl. m1
Jan. 1.80520 5 01 31.45 +31 30 19.5 12.8
1.81741 5 01 31.14 +31 30 18.5
4.73590 5 00 10.57 +31 25 00.2 13.0
4.74499 5 00 10.53 +31 25 00.1
5.76730 4 59 43.26 +31 23 04.2 13.3
5.77841 4 59 43.09 +31 23 04.8
7.75851 4 58 52.16 +31 19 20.1 13.3
7.76985 4 58 51.91 +31 19 18.9
8.75281 4 58 27.51 +31 17 25.4 13.0
8.76427 4 58 27.31 +31 17 25.8
16.01759 4 55 46.58 +31 03 18.9 13.2
16.02911 4 55 46.33 +31 03 18.2
PERIODIC COMET CHERNYKH (1977l)
The following precise positions have been reported:
1977/78 UT R. A. (1950) Decl. m1 Observer
Nov. 17.05266 23 55 05.46 - 7 42 17.2 Schwartz
Dec. 7.11285 0 04 38.65 - 6 16 35.4 Giclas
Jan. 1.71058 0 28 03.18 - 3 11 06.7 15.0 Mrkos
1.72204 0 28 03.92 - 3 11 01.2 "
4.70755 0 31 27.82 - 2 45 15.7 15.0 "
5.70816 0 32 37.84 - 2 36 24.4 15.2 "
5.72008 0 32 38.38 - 2 36 23.6 "
6.78375 0 33 53.88 - 2 26 49.8 15.0 Rutter
7.72066 0 35 01.00 - 2 18 32.6 15.2 Mrkos
7.73148 0 35 01.83 - 2 18 27.3 "
8.71826 0 36 13.16 - 2 09 34.0 15.2 "
8.72972 0 36 14.05 - 2 09 27.9 "
G. Schwartz (Harvard Observatory). Measurer: J. H. Bulger.
H. L. Giclas (Lowe11 Observatory) Measurer: M. L. Kantz.
A. Mrkos (Klet Observatory). 62.5-cm Maksutov camera.
G. H. Rutter (Woolston Observatory). Measurer: R. L. Waterfield.
1978 February 10 (3171) Brian G. Marsden
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