THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
INTERNET: aavso@aavso.org
Tel. 617-354-0484 FAX 617-354-0665
AAVSO ALERT NOTICE 242 (November 3, 1997)
SUPEROUTBURST OF 2110+13 EF PEGASI
We have been informed by Thomas Burrows (Novato, CA) and Patrick
Schmeer (Bischmisheim, Germany) that the dwarf nova type (SU UMa
subclass) cataclysmic variable EF Peg is in superoutburst, as
indicated by the following observations: Nov 1.93 UT, <13.0 (P.
Schmeer); 2.1868, 11.4 (Burrows); 2.713, 11.1 (Schmeer); 2.750,
10.8 (Schmeer); 2.760, 10.7 (Schmeer); 2.835. 10.7 (Schmeer);
3.0771, 11.2 (G. Hanson, Cave Creek, AZ); 3.1604, 10.9 (R. Royer,
Lakewood, CA); 3.1750, 11.2 (Hanson); 3.1951, 11.6 (Burrows);
3.2076, 11.3 (Hanson); 3.779, 11.2 (E. Broens, Mol, Belgium);
3.795, 11.3 (E. Muyllaert, Oostende, Belgium).
The last two superoutbursts of EF Peg were in October 1991 and
January 1995 (see AAVSO Alert Notice 196) and they were both
first detected by P. Schmeer. Both superoutbursts lasted about
three weeks. The orbital period of the system was estimated to be
2.05 hours from the observed superhump period of 2.09 hours
during the 1991 superoutburst (see S. Howell et al. 1993,
P.A.S.P., 105, 579).
EF Peg has a close companion about 5 arcseconds away at position
angle 305 degrees. In making a magnitude estimate, observers are
recommended to use high magnification and to be particularly
careful of this companion. When reporting observations of EF Peg
during outburst, please indicate whether your estimate is a
combined magnitude or not.
Please monitor the current superoutburst of EF Peg, using the
accompanying "f" scale (5"/1mm) AAVSO preliminary chart, and
report your observations to AAVSO Headquarters. This chart has
been been posted on our ftp site; see below for details. When
reporting observations please indicate the source and the date of
the chart, as well as the magnitude of the comparison stars used.
Observers, particularly those using CCDs are encouraged to search
for superhumps (small amplitude, periodic oscillations during
superoutburst) by observing EF Peg every three to five minutes
for several hours. Please report the time of your observations to
four decimal places of the day.
Also posted on our ftp site is AAVSO Alert Notice 196 which gives
details of the Jan. 1995 superoutburst of EF Peg, together with
the history of the comparison star magnitude sequence of the
AAVSO chart.
We congratulate Tom and Patrick on their detection of this
outburst of EF Peg!
REQUEST TO MONITOR 0749+22 U GEMINORUM FOR OBSERVATIONS WITH EUVE
and RXTE
We are collaborating with astronomers from Lawrence Livermore
National Laboratory in the observations of U Gem in an exciting
observing program that will involve the Extreme Ultraviolet
Explorer (EUVE) and the Rossi X-ray Timing Explorer (RXTE). These
satellites have been scheduled to observe U Gem as a target-of-
opportunity object as soon as it starts to go into its next
outburst.
The investigating astronomers have requested that we inform them
immediately when U Gem starts to brighten so that they can cover
the rise to maximum with the satellites, particularly with the
EUVE which observed U Gem at maximum during its December 1993
outburst. The aim in the forthcoming observations is to observe
the rise to maximum in order to fill in the gap. Thus, the early
notification of the outburst is crucial.
Please monitor U Gem closely, and inform us immediately by phone,
fax, or email when it starts to brighten, i.e. becomes brighter
than 13.5. Once U Gem goes into outburst, please send in your
observations daily so we may keep the astronomers informed of the
star's behavior. The success of the observing run very much
depends on your observations and the early alerts and continuous
information we can provide to our colleagues.
CHARTS AVAILABLE ON AAVSO FTP SITE
Chart links obsolete, 11/2013: Create charts using VSP at http://www.aavso.org/vsp
Electronic copies of the AAVSO chart of EF Peg mentioned in this
Alert Notice are available from our FTP site:
ftp.aavso.org (198.116.78.2), in /pub/alerts/alert242
or
ftp.aavso.org (198.116.78.2), in /pub/charts/peg/ef_peg
The chart may also be accessed through our Web site at the
following address:
http://www.aavso.org
The answering machine at AAVSO Headquarters is on nights and
weekends for your convenience. Please call our charge-free number
(800-642-3883) to report your observations. We also encourage
observers to send observations by fax to 617-354-0665 or by e-
mail through the Internet to observations@aavso.org.
Many thanks for your valuable astronomical contributions and your
efforts.
Good observing!
Janet A. Mattei
Director
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