V854 Cen is a fine R Coronae Borealis star for southern observers, reaching binocular brightness at maximum, but diving below 14th magnitude at minimum. It entered the AAVSO observing program relatively recently (1986), but has been well-observed by southern observers since. R CrB stars are highly evolved stars whose light variations are believed to be caused by obscuration by dust which they themselves generate. Their variations are often characterized by months or years of steady brightness, puncuated by rapid, irregular fadings of several magnitudes followed by gradual (but often irregular) returns to their maximum brightness level. V854 Cen is a fine example of this, showing several such fading and rebrightening events over the 2500-day light curve shown.
In 2012, the AAVSO observer community is providing assistance to Bram Ocshendorf of Leiden Observatory and his collaborators studying the spectral properties of V854 Cen in decline. As announced in Alert Notice 456, continued monitoring is requested, and early indications of any fade should be reported as quickly as possible via WebObs -- they will be used to trigger spectroscopic observations with the VLT in Chile.
Prepared By: Matthew Templeton