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Alert Notice 206: Rare outburst of 1227+14 AL Comae Berenices

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

AAVSO ALERT NOTICE 206 (April 5, 1995)

RARE OUTBURST OF 1227+14 AL COMAE BERENICES

David York, Abiquiu, NM, has reported the brightening of AL Com, and Tom Cragg,
Coonabarabran, NSW, Australia, has confirmed the outburst, as indicated by the
following observations: Apr 5.1486 UT, 14.9, D. York; 5.6000, 12.7, T. Cragg.

The data file on AL Com in the AAVSO International Database goes back to 1967,
and it indicates that this cataclysmic variable has had two outbursts, one in
April 1974, when it reached magnitude 14.0 and was in outburst (brighter than
magnitude 15.0) for four days, and one in March 1975, when it reached magnitude
12.8, slowly faded to magnitude 14.9 in 18 days, and stayed at around that
brightness for another 12 days before fading to minimum.  Since then, the star
has been well monitored and it has been at minimum; most of the observations
in the database are fainter than 15.0 (<15.0).  S. Howell, Planetary Science
Institute, communicates via vsnet that AL Com is near magnitude 20.5 at minimum.

Please use the accompanying AAVSO "e" scale preliminary chart with photoelectric
sequence by R. Stanton to observe AL Com.  Both visual and, particularly, CCD
observers are urged to search for superhumps while this star is at maximum.
To search for superhumps, please observe AL Com as often as you can, preferably
every 5 minutes or less and record your observations very carefully, recording
the exact time of your observations.  If AL Com is an SU UMa-type cataclysmic
variable, and has superhumps, then the superhump period should be less then
two hours.

We congratulate Dave on his discovery of AL Com in outburst, and we thank
Tom for confirming it.

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

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 at
617-354-0665 or by e-mail through the Internet at aavso@cfa.harvard.edu.

When telephoning in observations, please state the name of the star, the
magnitude, and the time of the observation.  The preferred time is either your
local time (be sure to state the time zone and whether it is Standard or
Daylight Savings Time) or Universal Time.  You do not need to give the
designation of the star.   Please also include the comparison stars you have
used in making the observation.

Many thanks for your dedicated efforts and valuable astronomical contributions.

Good observing,

Janet A. Mattei
Director

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