R CrA & cyclic brightness variations in NGC 6729
An indicative unfiltered light curve has been generated for the protostar R CrA. During the period 2018 May to 2020 November, the variability was seen to be substantial (11.5–13.1), but only weakly compliant with the 65.7-day variability generally attributed to R CrA. The star illuminates the fan-shaped NGC 6729 nebula. Variability in the nebula was observed to begin close to R CrA and then move steadily down the fan, fading as it progressed. Measurements of the surface brightness of the different parts of the nebula showed an apparent relationship in the delay between brightening of R CrA and the subsequent brightening of parts of the fan. These variations appear consistent with light echoes.
Read more