AAVSO Special Notice #1 (December 8, 2005)
      Exoplanet Transit Campaign for Southern Hemisphere

  Dr. Greg Laughlin (UCO Lick Observatory/Transitsearch.org) and Dr.
David Blank (James Cook University) are conducting a photometric
monitoring campaign for exoplanet transits of HD 13445. The windows
for possible transit are:

         December 11 20:51 - December 12 05:00 (UT)
         December 27 14:58 - December 27 23:36 (UT)
 
  HD 1334 is located at RA 02:10:14.4 and Dec. -50:50:0.5 (J2000).

  The possible transit times are estimates so observing before and
after the windows is encouraged. HD 13445 is bright at V=6.17 so
observing will be a challenge. For help, consult the Transitsearch 
Mailing List available at www.transitsearch.org. Also, advice is 
available in the bright star photometry section of the AAVSO CCD 
Observing Manual at the URL below:

http://www.aavso.org/observing/programs/ccd/manual/4.shtml#7

  If there is a transit, the estimated amplitude is 0.021 magnitudes
and estimated duration is 273 minutes. A chart is not planned at this
time.

  The campaign is being coordinated through the Transitsearch Mailing
List. A circular announcing the campaign is available in the News 
section of their web site at the previously mentioned URL. The following 
background is written by Dr. Blank and reprinted from the circular 
with permission:

  "HD 13445 is a nearby (d=11 pc) K1 V star accompanied by a planet
that is at least four times as massive as Jupiter. Seagroves et al.
(2003) classify HD 13445b as an intermediate period
 exoplanet since the orbital period of 15.8 days is longer than those
of the so-called hot Jupiters . Intermediate period planets will have
significantly cooler atmospheres than the hot jupiters, and are
expected to be characterized by very different atmospheric chemistry
and dynamics. To date, however, there have been no observed transits
of intermediate period exoplanets. The discovery of such a transit
would be valuable because it would give us the basic physical
properties (radius, mass and density) of a giant planet whose
estimated temperature of T ~ 600 K is in a completely unexplored
regime. Furthermore, the bright magnitude of the parent star would
make HD 13445 b an ideal candidate for high-resolution follow-up.
Getting these basic properties would give information about the
internal structure of the planet and possibly its formation.
Spectroscopically, the planet is likely a member of the yet-unobserved
Y dwarf class, in which the spectral features are expected to be
dominated by Ammonia lines...
  "It will probably take observations over at least two or three
windows before one can be sure whether the planet is transiting or
not."

   Observations should be submitted to the AAVSO as either "HD 13445" 
or "0206-51". They will be compiled and submitted to Dr. Laughlin and 
Dr. Blank. Good luck!
 
References  
  Seagroves, S., Harker, J., Laughlin, G., Lacy, J., and Castellano, 
T. P. 2003, PASP, 115, 1355 

  This special notice was written by A. Price.
--------------------------------------------------------------------
 
   To unsubscribe from the AAVSO Special Notice electronic 
announcements reply to this e-mail with "unsubscribe" in the 
Subject line. 

   Archives of past Special Notices are available at:
   http://www.aavso.org/publications/specialnotice/