AAVSO Special Notice #177
Observing Campaign on the Secondary Eclipse of zeta Aurigae
November 12, 2009
As part of the AAVSO's Citizen Sky Project experienced observers are encouraged to contribute high precision observations of zeta Aurigae during the remainder of the month of November. The nature of this system makes the secondary eclipse very difficult to observe with a minimal change in brightness. Characterization of the secondary eclipse will be a challenging endeavor to observers. Zeta Aurigae is a bright (V ~ 3.75 out of eclipse), northern eclipsing variable with a known period of 2.66 years. The system contains a hot, luminous B7V star and a more luminous K5II star. During primary eclipse (which occurred in March 2009), the blue B7V star is obscured by the larger orange K5II star. The secondary eclipse is more difficult to detect, because the B7V star obscures a small portion of the K5II star's light. The approximate date of the eclipse is November 17, 2009, with an anticipated duration of about 40 days. The K5II star is known to exhibit variations of 0.05 magnitude, therefore high precision photometry is necessary for this short campaign. For more information,including comp star coordinates and magnitudes, please visit: http://www.citizensky.org/forum/mini-observing-campaign-secondary-eclipse-zeta-aurigae This AAVSO Special Notice was prepared by B. Kloppenborg and A. Henden. --------------------------------------------------- SUBMIT OBSERVATIONS TO THE AAVSO Information on submitting observations to the AAVSO may be found at: http://www.aavso.org/observing/submit/ SPECIAL NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION A Special Notice archive is available at the following URL: http://www.aavso.org/publications/specialnotice/ Subscribing and Unsubscribing may be done at the following URL: http://www.aavso.org/publications/email/