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          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 272 (March 13, 2000)

1301-27 SUPERNOVA 2000P IN NGC 4965 IN HYDRA

We have been informed by the Central Bureau for Astronomical Telegrams
(IAU Circular 7378) that F. Colas, Institut de Mecanique Celeste, Paris, and
Observatoire du Pic du Midi, reports the discovery by Robin Chassagne,
Sainte Clotilde, Ile de Reunion, of an apparent supernova in NGC 4965 at
magnitude 14.1 CCD (unfiltered) on Mar 8.03 UT.  Colas confirmed the presence
of the object at CCDR magnitude 14.5, and noted that it does not appear on the
Digital Sky Survey down to about magnitude 21.

Colas reported the position of Supernova 2000P, located 16" east and 21" south
of the center of NGC 4965, as:

    R.A. = 13h 07m 10.53s   Decl. = -28 degrees 14' 02.5"  (epoch 2000)

J. Ripero Osorio, Madrid, Spain, report to the AAVSO that the supernova
was <14.0 on Mar 13.020 UT.

Accompanying is an AAVSO "e" scale preliminary chart prepared by C. Scovil
showing the location of the supernova.  Please use this chart to observe
1301-27 SN 2000P and report your observations to AAVSO Headquarters, making
sure to indicate which comparison stars you used.

Congratulations to Robin Chassagne on discovering this apparent supernova!

1247-28 EX HYDRAE - MULTIWAVELENGTH OBSERVING CAMPAIGN SCHEDULED

Astronomers at the Planetary Science Institute in Tucson, Arizona, have
scheduled an international multiwavelength observing campaign on the
cataclysmic variable EX Hya from May 5 through June 10.  Our assistance has
been requested to provide close visual coverage during the satellite campaign
in order to help correlate the observations obtained from x-ray to infrared by
the different satellites.

EX Hya is an intermediate polar, which is an interacting binary subtype of
cataclysmic variable (CV).  It is the only CV to show emission lines in the
extreme ultraviolet (EUV) spectral region when not in outburst.  The
astronomers inform us that they have obtained 1000 continuous kiloseconds
of
observing time with the EUVE satellite between May 5 and June 10, which will
be the longest single observation ever performed by the satellite for a star.
When they observe EX Hya with the EUVE, the astronomers will be able to make
the first-ever detailed observations of plasma diagnostics in any source other
than hot-star chromospheres such as Capella's.  They report that extending
EUV plasma observations to other systems and at other wavelengths is a crucial
test of models and has applications spanning hot stars, neutron star binaries,
and AGNs.

Thus, good optical coverage during the observing interval is essential to the
success of this program.  Please monitor EX Hya very closely from now through
the end of June, and especially closely between May 5 and June 10.
Observations
made every 5 minutes for as long as possible every clear night would be very
valuable.  Please record the time of your observations to three decimal places
and report your observations of EX Hya to AAVSO Headquarters so we may keep
the astronomers informed of its status.

For observers who have access to CCD, we strongly recommend CCD observations
every 5 minutes for as long as possible.  If you can carry out BVRI CCD
observations, please contact AAVSO Headquarters for information on the BVRI
comparison star magnitudes.

Accompanying is an "e" scale AAVSO preliminary chart of EX Hya.  Please use
this chart to observe EX Hya, and be sure to indicate which comparison stars
you used to make your estimates when you report your observations.

Your participation is essential to the success of this ground-breaking
observing campaign!

CHARTS AVAILABLE ON AAVSO WEB AND FTP SITES

Electronic copies of the charts of SN 2000P and EX Hya mentioned in this Alert
Notice are available through our web site at the following address:

                         http://www.aavso.org

The charts may also be obtained directly from our FTP site:

             ftp.aavso.org (198.116.78.5), in /alerts/alert272

The answering machine at AAVSO Headquarters is on nights and weekends for
your convenience. Please call our charge-free number (888-802-STAR =
888-802-7827) 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

Elizabeth O. Waagen
Senior Technical Assistant




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