December 15, 2015: Further to AAVSO Alert Notice 503 and AAVSO Special Notice #409, Dr. Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) urgently requests that multicolor and visual AAVSO observations of the symbiotic variable RT Cru continue.
The long period variable R Aquarii is an extremely interesting system. Its type is both Mira (M) and symbiotic (ZAND) - R Aqr is a close binary system consisting of a hot star and a late-type star, both enveloped in nebulosity. In the case of R Aqr, the late-type star is a Mira. As a result, the very interesting light curve shows not only the Mira pulsation but also eclipses as the two stars interact.
October 30, 2015:Further to AAVSO Alert Notice 503, Dr. Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) informs us that the Chandra observations of the symbiotic variable RT Cru have been scheduled.
October 30, 2015: Dr. Peter Kuin (Mullard Space Science Laboratory, University College London) and colleagues in the Swift Nova group have requested AAVSO observers' assistance in multicolor monitoring of V5668 Sgr (Nova Sgr 2015 No. 2, see AAVSO Alert Notices 512, 519) in support of an upcoming spectroscopic observation with the Hubble Space Telescope Imaging Spectrograph (STIS).
October 20, 2015:The AAVSO requests time-series observations of the enigmatic variable object KIC 8462852 beginning immediately and continuing through at least the end of the current observing season. The star is relatively bright (V=11.88) and shows aperiodic dips of a few tenths of a magnitude, the causes of which are unknown. The object is not known to be a close binary or a young stellar object, and there are no other typical indicators of circumstellar material such as infrared emission.
October 2, 2015: Further to AAVSO Alert Notice 511, issued in March 2015, Dr. George Rieke (University of Arizona) and colleagues' campaign to monitor planetary debris disks for variability using the Spitzer Space Telescope continues. AAVSO observations are requested to rule out variability of the stars themselves.
The second segment of observations of the four targets takes place from now into January 2016 according to the schedule below.
October 1, 2015: Dr. George Wallerstein (University of Washington) has requested AAVSO assistance in monitoring 5 variable stars in Cygnus now through December 2015. He is working to complete the radial velocity curves for these stars, and needs optical light curves for correlation with the spectra he will be obtaining.