Central Bureau for Astronomical Telegrams
IAUC 4174: TERZAN 2; 1985q; 1985n
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Circular No. 4174
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 617-495-7244/7440/7444
TERZAN 2
B. M. Belli, Istituto Astrofisica Spaziale, Frascati; F.
d'Antona, Osservatorio Astronomico, Roma; D. Molteni, Istituto
Fisica Universita, Palermo; and M. Morini, Istituto Fisica Cosmica e
Informatica, Palermo, telex: "Analysis of an 11-hr observation,
made with the EXOSAT medium-energy experiment and beginning 1985
Mar. 14.16 UT, of the x-ray source in the globular cluster Terzan 2
(= 4U 1722-30) shows evidence of quasi-periodic oscillations (QPOs)
at a constant level of the source flux (1.3 x 10**-13 J m**-2 s**-1) in
the energy range 2-8 keV. The average centroid frequency is 0.092
+/- 0.001 Hz, the FWHM is 0.0053 +/- 0.002 Hz, the rms (pulsed fraction)
is 4.8 +/- 1.2, and the statistical significance > 5 sigma. Low-
frequency noise and the second harmonic are also present. The QPOs
show a hard spectrum, appearing with rms 5.6 +/- 1.6 significance
> 4.5-sigma) in the hard part of the analyzed range (4-8 keV) and
irrelevant (rms < 2, significance < 2-sigma) in the soft part (2-4 keV)."
PERIODIC COMET WIRTANEN (1985q)
Ephemeris from elements corrected as indicated on IAUC 4139:
1986 ET R.A. (1950.0) Decl. p r m1
19 0 51.27 + 0 35.1 1.657 1.146 11.2
Mar. 1 1 24.22 + 5 23.9
11 1 59.62 +10 18.8 1.605 1.090 10.9
21 2 37.70 +15 08.1
31 3 18.51 +19 37.2 1.591 1.096 10.9
Apr. 10 4 01.89 +23 30.6
20 4 47.24 +26 34.1 1.637 1.163 11.2
Total visual magnitude estimates by A. Hale, Bishop, CA, with
a 0.20-m reflector: Feb. 2.17 UT, 11.5; 3.13, 11.4.
PERIODIC COMET BOETHIN (1985n)
Further total visual magnitude estimates: Jan. 12.00 UT, 8.2
(J. E. Bortle, Stormville, NY, 20x80 binoculars); 12.96, 7.3 (D. W.
E. Green, Oak Ridge Obs., 20x80 binoc.); 14.09, 8.4 (R. Keen, Mt.
Thorodin, CO, 0.32-m refl.); 21.10 7.6, (C. E. Spratt, Victoria,
BC, 0.80-m refl.); 28.10, 7.2 (Spratt, 11x80 binoc.); Feb. 2.10,
7.2 (Spratt); 3.16, 8.5 (A. Hale, Bishop, CA, 10x50 binoc.).
1986 February 5 (4174) Daniel W. E. Green
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