Central Bureau for Astronomical Telegrams
IAUC 3326: 2A 0311-227; 1977d
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Circular No. 3326
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
2A 0311-227
R. E. Griffiths and the HEAO-A3 Group of Harvard-Smithsonian
Center for Astrophysics and Massachusetts Institute of Technology;
M. J. Ward, Institute of Astronomy, University of Cambridge; J. C.
Blades, Anglo-Australian Observatory; and A. S. Wilson, University
of Maryland, report the optical identification of the x-ray source
2A 0311-227 (cf. IAUC 3324) with an AM-Her-type star. The source
was precisely located by the HEAO-1 scanning modulation collimator,
with resulting positional errors of 20" x 2', and there is only one
star brighter than magnitude 19 within these errors. Spectrograms
of this ~ fifteenth-magnitude star (R.A. = 3h12m00s.0, Decl. = -22o46'49",
equinox 1950.0) were taken at the Mt. Stromlo 190-cm telescope
using the Cassegrain spectrograph and photon counting array on 1978
Nov. 27 and at the 390-cm Anglo-Australian telescope using the RGO
spectrograph and Image Photon Counting System on Dec. 2. The
medium-dispersion spectra revealed an intense Balmer series in emission
from H-alpha through H-10, together with a strong Balmer continuum.
Emission lines were also observed at He I 4026, 4471 4921, 5015 and
5876 A; He II 4686 A; and C III-N III 4640 A. In view of the remarkable
similarity of this spectrum to that of AM Her, including the
unusual Balmer decrement, the x-ray source is identified with this
new member of the AM-Her class.
D. R. Hearn, Massachusetts Institute of Technology, reports
that 2A 0311-227 was scanned with the x-ray detectors on SAS 3 between
1975 Dec. 22.1 and 1976 Jan. 2.4 UT. An average x-ray flux
of 2 x 10**-11 erg cm**-2 s**-1 was detected in the 0.15-0.28-keV channel.
Two individual scans with the best exposure to the source yielded
3-sigma detections. (The 0.4-0.8-keV flux was less than 10**-10 erg cm**-2
s**-1.) A fold of the x-ray data with the optical orbital period of
81 +/- 5 min reported by Boley et al. (IAUC 3324) provides weak
evidence that the soft x-ray flux is modulated by 50-100 percent. The
approximate epoch of x-ray minimum is 1975 Dec. 27.787 UT.
PERIODIC COMET TEMPEL 2 (1977d)
B. Zellner, E. Tedesco and J. Degewij, Lunar and Planetary
Laboratory, report the following observations, obtained using the
154-cm reflector and 13" focal-plane diaphragm with a two-channel
star-sky chopping photometer: Jan. 28.15 UT, V = 18.40 +/- 0.13, B-V =
+0.60 +/- 0.19; Jan. 31.17, 18.65 +/- 0.24, +0.69 +/- 0.38. The comet
was stellar in appearance within the limits of seeing (~ 4").
1979 February 7 (3326) Brian G. Marsden
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