Central Bureau for Astronomical Telegrams
IAUC 4517: EXO 033319-2554.2; N Vul 1987
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Circular No. 4517
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
EXO 033319-2554.2
K. Beuermann, H.-C. Thomas and A. Schwope, Max-Planck-Institut
fur Extraterrestrische Physik, Garching, and Technisches
Universitat, Berlin, report: "Spectrophotometric observations of the
recently discovered AM-Her star EXO 033319-2554.2 (IAUC 4486) with
the ESO/MPI 2.2-m telescope at La Silla during Oct. 20-26 confirm
the system to be an eclipsing binary with period 126.5 min.
During the cyclotron bright phase the system reaches V = 18.2; it
drops to V = 20.9 in eclipse, consistent with the contribution
from the dM5 secondary. The magnetic nature of the system is
confirmed by the detection of pronounced cyclotron lines, with the
third, fourth and fifth harmonics peaking at 670, 510 and 415 nm.
The implied field strength in the emission region is about 50 MG,
the highest field strength detected so far in AM-Her binaries."
J. Bailey, Anglo-Australian Observatory; L. Ferrario, I. R.
Tuohy and D. T. Wickramasinghe, Australian National University;
and J. H. Hough, Hatfield Polytechnic, telex: "Observations with
the Anglo-Australian Telescope confirm that EXO 033319-2554.2 is
an eclipsing AM Her-type binary. Spectroscopy on Nov. 27 showed
the object to be in a bright state (V about 17) with strong Balmer and
He II 468.6-nm emission lines. Deep eclipses were seen with a
period of about 127 min, in agreement with Giommi et al. (IAUC 4486).
On Dec. 15 circular polarization reaching about +10 percent was
observed lasting for about 50 min of the 127-min cycle in a broad
blue band (330-530 nm). Polarization levels in the red were much
lower (2 percent or less in the I band). The eclipse occurs near
the end of the polarized phase, lasts for about 7.5 min and reaches
mid-eclipse magnitudes of about V = 20.5, I = 17.7."
NOVA VULPECULAE 1987
Photoelectric photometry by D. Bohme, Nessa, East Germany,
with a 0.25-m Cassegrain telescope: Nov. 29.701 UT, V = 7.45, B-V
= +0.59; Dec. 3.728, 7.33, +0.60.
Visual magnitudes: Nov. 23.73, 7.0 (P. Schmeer, Bischmisheim,
West Germany); 27.07, 7.5 (P. Collins, Scottsdale, AZ); Dec. 2.07,
7.2 (Collins); 8.06, 7.7 (Collins); 13.71, 7.6 (E. Schweitzer,
Strasbourg, France); 15.73, 7.8 (S. Baroni, Milan, Italy); 16.06,
8.1 (Collins); 19.73, 7.7 (Schmeer); 20.71, 7.7 (A. Boattini,
Piazzano, Italy); 21.78, 8.2 (A. Pereira, Linda-A-Velha, Portugal).
1987 December 22 (4517) Brian G. Marsden
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