Variable Stars - RZ Psc
Type X Orionis Click for lightcurve X Orionis stars are collectively known in the literature as UXors. Subgroup of Young Stellar Objects that show irregular variations with a wide range of amplitudes from barely detectable to more than 4 mag in V. Most of them are Herbig Ae/Be stars but there are some T Tauri stars with later spectral types also showing the same behaviour. Large-amplitude variability is confined to stars with spectral types later than B8. There are two principal components: (1) irregular variations on time-scales of days around a mean brightness level that changes on a much longer time-scale (typically years), sometimes in a quasi-cyclic fashion, and (2) occasional episodes of deep minima, occurring at irregular intervals but more frequently near the low points of the brightness cycles. UXors show increased polarization when the optical light of the star becomes fainter (presence of clumps in our line of sight) and redder, while in extreme visual minima there is a color reversal. Currently mixed among the ISA, INA or INSA classes in the GCVS. AAVSO Special Notice #408  October 2, 2015 Developing planetary systems dust production study - second segment of observations 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. Mar 14-Apr 24 Oct 10-Nov 20
Hills Observatory: 1 January 2013 to 6 May 2018
COMETS COMETS
DEEP SKY DEEP SKY