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Alert Notice 196: Outburst of 2110+13 EF Pegasi AND Request to monitor some Hipparacos red variables for photometric calibration

THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
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INTERNET:  aavso@cfa.harvard.edu
Tel. 617-354-0484       FAX 617-354-0665

AAVSO ALERT NOTICE 196 (January 12, 1995)

OUTBURST OF 2110+13 EF PEGASI

We have been informed by Patrick Schmeer (Bischmisheim, Germany) that the
cataclysmic variable EF Peg is in outburst, as indicated by the following
observations: Jan 5.732 UT, <13.0 (Schmeer); 9.988, <13.5 (J. Bortle,
Stormville, NY); 11.726, 11.1 (Schmeer); 11.740, 11.1 (Schmeer); 11.744,
11.1 (Schmeer).  The outburst was confirmed by G. Poyner (Birmingham, England)
on Jan 11.744 UT at 11.1.  

EF Peg is in the dwarf nova class of cataclysmic variables.  Within that class,
it is an SU Ursae Majoris-type star.  Until recently, EF Peg was a poorly-
studied dwarf nova, with a large amplitude, varying from about 18th magnitude
to about 10.9.  Its last superoutburst was also first detected by P. Schmeer
on October 15, 1991, when it reached 10.9.  The superoutburst, which was the
first visually-detected and well-monitored superoutburst, lasted about
three weeks, and during this superoutburst, S. Howell et al. observed
superhumps with a period of 2.09 hours.  From this information they estimated
the orbital period of the system to be 2.05 hours (see Howell, S. B., Schmidt,
R., DeYoung, J. A., Fried, R., Schmeer, P., Gritz, L. 1993, P.A.S.P., 105,
579; Howell, S. B., and Liebert, J., 1994, IBVS, No. 4073; Gessner, H., 1988,
IBVS, No.3209, for discussions on photometry of 1991 superoutburst,
spectroscopy, and outburst interval length, respectively). 

Please monitor the current outburst (possibly a superoutburst, since it is
bright) of EF Peg, using the accompanying f scale (5"/1mm) AAVSO preliminary
chart, and report your observations to AAVSO Headquarters.  

EF Peg has a close companion about 5 arcseconds away at position angle 305
degrees.  Be particularly careful of this companion, and when reporting
magnitude estimates of EF Peg during outburst, indicate whether your estimate
is a combined magnitude or not.  During quiescent intervals, make sure of the
identification of EF Peg.  Some observers are reporting EF Peg at about 12.4
during quiescence - this magnitude estimate is that of the companion and not
of EF Peg. 

The history of the preliminary AAVSO finder chart for EF Peg is rather
interesting.  The first preliminary chart was issued by C. Ford in March 1973,
and it was revised in August 1976.  However, the comparison star magnitudes
in this old chart, mostly visual estimates, were too bright.  In October 1991,
a  revised preliminary AAVSO chart was issued by C. Scovil, on which the
photovisual magnitudes of the comparison stars around the variable as well
photoelectric magnitudes from Geneva Observatory of some bright stars were
given.  Later, T. Kato and T. Takata of Kyoto, Japan, obtained CCD(V)
magnitudes for closeby comparison stars, and the AAVSO preliminary chart was
revised in June 1993 to include these CCD(V) magnitudes and photoelectric
and photovisual magnitudes from the 1991 chart.  

In addition to the AAVSO finder chart, a chart with a similar (but not the
same) sequence has been issued by The Astronomer (TA).  Schmeer, who used the
TA sequence, informed us that the 10.5 star on the accompanying AAVSO chart
is 10.8 on the TA chart; AAVSO 10.2 is TA 10.6; AAVSO 11.4 is TA 11.3; and
AAVSO 12.1 is TA 12.4.  It is essential that observers indicate the source
and date of the finder chart and the comparison stars used in the observations
they report to the AAVSO.

This star is a good example of the essential need for observers to have the
most recent charts issued for the stars they are observing, and of the
inhomogeneities that exist in the variable star data files from the different
comparison star magnitudes coming from different sources.  Both the observers
and those of us from different associations/groups working with the charts and
the data are aware of this situation, and we are trying to find a solution so
that all observers will use the same sequence for a star.  Until a solution is
found, however, it is CRUCIAL that observers indicate the source and date of
each chart they are using.

REQUEST TO MONITOR SOME HIPPARCOS RED VARIABLES FOR PHOTOMETRIC CALIBRATION

Astrometric and photometric data from the Hipparcos satellite, which operated
between August 1989 and August 1993, are now being processed so that they can
be made public by the end of 1996.  Throughout the mission, AAVSO data on long
period variables were used in order to predict the brightness of these
variables so that the correct amount of satellite time could be allocated
for their observation.  

In order to calibrate the satellite photometry of red variables, multicolor
data are needed.  While CCD and photoelectric photometry are being carried
out on some of the red variables, we have been requested to provide visual
data on these stars in order to check the calibration.  Observers,
particularly those in the southern hemisphere, are strongly recommended to
monitor as many of the stars listed below as possible once a week throughout
January and February, and report their observations to Headquarters as early
as possible.  If you need finder charts for any of the stars, please let us
know by telephone, email, or fax, and we will provide them free of charge.

                                Range  |                                Range 
Desig.   Star     Type Period  max  min|Desig.   Star     Type Period  max  min
                                       |                                      
0010-32  S SCL    M    362.5   6.7 12.9|0617-02  V MON    M    340.5   7.0 13.2
0016-20  T CET    SR   158.9   5.0  6.9|0653-08  V523 MON SR    45.    7.0  7.5
0022-12  AG CET   SR    90.    7.0  7.5|0656-14  RV CMA   L            8.6  9.8
0122-33  R SCL    SR   370.    6.6  9.0|0705-58  AC CAR   SR    99.    7.6  8.8
0214-03  OMI CET  M    331.9   3.6  9.2|0702-07  RY MON   SR   455.7   7.5  9.2
0243-12  Z ERI    SR    80.    5.5  7.1|0718-25  VY CMA                6.5  9.6
0247-08  RR ERI   SR    97.    5.9  7.7|0724-04  RX MON   M    345.7   8.8 13.9
0250-50  R HOR    M    407.6   6.0 13.1|0731-73  S VOL    M    394.8   8.8 13.5
0301-59  V HOR    SR           7.2  8.3|0753-43  SU PUP   M    339.8   8.5 13.5
0328-26  RZ FOR   SR    64.6   7.7  8.5|0806-37  AS PUP   M    324.6   8.2 10.7 
0343-07  BR ERI   SR   175.5   6.9  8.2|0812-13  SV PUP   M    166.5   8.0 11.4 
0351-24  T ERI    M    252.2   8.0 12.8|0824-05  RT HYA   SR   290.    7.0 10.2
0359-16  V ERI    SR    97.0   7.3  8.9|0841-27  R PYX    M    364.7   9.0 12.4 
0417-05  RW ERI   SR    91.4   8.7 10.2|0925-51  Y VEL    M    449.9   8.8 13.6
0437-38  R CAE    M    390.9   8.1 13.1|0929-62  R CAR    M    308.7   4.5  9.7
0443-36  T CAE    SR   156.    6.5  8.4|0930-14  X HYA    M    301.1   8.3 12.8
0500-22  T LEP    M    368.1   8.2 12.9|0945-01  W SEX    SR   134.0   7.9 10.1
0504-05  SY ERI   SR    96.0   8.0  8.9|0946-22  Y HYA    SR   302.8   6.5  9.0
0508-48  S PIC    M    428.0   8.0 13.4|0951-41  X VEL    SR   140.    8.7  9.9
0506-11  RX LEP   SR    60.    5.0  7.4|1006-61  S CAR    M    149.4   5.7  8.6 
0515-33  T COL    M    225.8   7.5 11.9|1011-53  W VEL    M    394.7   8.8 13.3
0524-04A S ORI    M    414.3   8.6 13.0|1016-34  V ANT    M    302.7   8.3 13.0 
0540-46  W PIC    L            7.1 10.2|1029-83  X OCT    SR   206.8   7.2 11.2
0543-31  S COL    M    325.8   9.3 13.4|1044-53  WX VEL   M    411.5 1 0.5 12.1
0548-01  NSV 2721 L                    |1046-20  V HYA    SR   530.7   7.0 13.0
0601-24  S LEP    SR    89.0   6.0  7.6|1150-58  W CEN    M    201.5   8.4 13.2

Chart links are obsolete; 11/2013 create charts using VSP at http://www.aavso.org/vsp

Many thanks for all your efforts and your astronomical contributions.  Best
wishes to your loved ones for a very happy and fulfilling new year, with
clear skies and good observing!

Janet A. Mattei
Director

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