Central Bureau for Astronomical Telegrams
IAUC 3180: U Gem; Poss. OPTICAL COUNTERPART FOR GT 0236+610; HR 1099
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Read IAUC 3181
Circular No. 3180
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
U GEMINORUM
J. Mattei wishes to inform those interested in making x-ray
observations of this star (cf. IAUC 3125) that visual observations by
AAVSO members indicate that the latest outburst was rather short-lived.
Magnitude estimates are: Feb. 23.06 UT, 13.1 (P. Goodwin,
Shreveport, Louisiana); 23.32, 13.0 (J. Morgan, Prescott, Arizona);
24.01, 10.0 (J. Bortle, Brooks Observatory); 24.14, 9.3 (R. Annal,
Barstow, California); 25.16, 9.5 (Goodwin); 26.03, 9.9 (G. Kelley,
Glade Springs, Virginia).
POSSIBLE OPTICAL COUNTERPART FOR GT 0236+610
R. Hjellming, D. Hogg and H. Hvatum, National Radio Astronomy
Observatory; and P. Gregory and R. Taylor, University of British
Columbia, report the following radio position for the highly variable
radio source GT 0236+610 (cf. IAUC 3164): R.A. = 2h36m40s.62 +/-
0s.14, Decl. = +61o00'54" +/- 1" (equinox 1950.0). The observations were
obtained with six antennae of the Very Large Array at 4885 MHz on
Feb. 11 and 12. The source flux density had a mean value of ~ 50
mJy but varied by almost a factor of two from Feb. 11 to 12. These
authors independently suggested the OB+ star LSI+61 303 (cf. IAUC
3170) as the optical counterpart, and their measured coordinates
from the Palomar Sky Survey prints, R.A. = 2h36m40s.60 +/- 0s.14, Decl. =
+61o00'54".1 +/- 1" (equinox 1950.0), confirm the identification.
D. Crampton and J. B. Hutchings, Dominion Astrophysical
Observatory, report that spectroscopic observations of LSI +61 303
reveal a highly reddened star of spectral type B1Ib with unusually
broad emission lines at H-alpha and H-beta. Sharp central absorption lines
are superimposed on the emission features, which have a total width
of ~ 900 km/s, in contrast to the 200 km/s width of the absorption
lines. Further photometric and spectroscopic observations should
be obtained to look for variability.
HR 1099
P. A. Feldman, Herzberg Institute of Astrophysics, informs us
that as of Feb. 24d20h UT this object was continuing to flare (cf.
IAUC 3176) at the ~ 0.5-Jy level, according to 2.8-cm observations
with the 46-m telescope of the Algonquin Radio Observatory.
1978 February 27 (3180) Brian G. Marsden
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