Central Bureau for Astronomical Telegrams
IAUC 3932: PG 1116+158; 2S 1254-690; Z And
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Read IAUC 3933
Circular No. 3932
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
PG 1116+158
D. E. Winget, R. E. Nather and S. O. Kepler, Department of
Astronomy and McDonald Observatory, University of Texas, communicate:
"The strong-line (He I) dB white-dwarf star PG 1116+158 is a
pulsating variable star. This brings to three the number of known
pulsating dB white dwarfs. The star was observed by using a high-
speed, two-star photometer with an RCA-8850 tube in unfiltered
light on the 2.1-m telescope. The lightcurve has a quasi-period
of ~ 1000 s with a peak-to-peak amplitude of 0.06 mag. Preliminary
power spectra of two runs (for 2.8 hr on Feb. 6 and for 1.9
hr on Feb. 28) indicate significant power near 1100 s and 800 s
with fractional amplitudes near 1.0 and 0.4 percent, respectively.
The star is a Palomar-Green survey object with B ~ 16.1, and
coordinates and finder charts are available on request to us at TWX
910-874-1351 TEXASTRO AUS."
2S 1254-690
T. J.-L. Courvoisier and A. Peacock, European Space Agency:
and M. Pakull, Technische Hochschule, Berlin, report the discovery
of the first type 1 x-ray burst clearly associated with 2S 1254-
690. The optical counterpart had been shown to be very similar to
counterparts of other x-ray bursters (Mason et al. 1980, Nature
287, 512), but no x-ray burst associated with this source had
previously been observed. EXOSAT observed the source for 6 hr on
Feb. 5. The burst occurred at 7h35m UT and was characterized by
two components: the first decayed in ~ 4.5 s and the second in ~
20 s. The temperature associated with the first component was
1.7 keV, and that associated with the slow decay was 1.1 keV. A
set of deep dips in the EXOSAT lightcurve occurred 10 min after
the burst. The lowest intensities registered then were near zero.
Z ANDROMEDAE
J. Mattei, AAVSO, reports that this symbiotic star, at minimum
and varying between mag 10.4 and 11.0 since 1974 (IAUC 3748),
has started to brighten. Magnitude estimates by J. Bortle (
Stormville, NY): Feb. 5.0 UT, 10.7; 23.1, 10.7; Mar. 27.4, 9.6. The
last major outburst (to mag 8.3) was in 1968. There were then four
successive outbursts of decreasing amplitude until the minimum.
1984 March 30 (3932) Brian G. Marsden
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