Proposal #84

RMC 40, the first discovered LBV in the Small Magellanic Cloud, is presenting a strong eruption, being, at this moment, the coolest eruption already observed (Campagnolo et. al, 2018). Our group was monitoring this star using telescopes in Brazil, 2-4 times by year. Perhaps, recently, we suspect that this star is presenting periodic variations in the order of 0.2 magnitudes, similar to published for RMC 71 by Mehner et. al (2017). Our data shows that these periodic variations can have timescales in the order of some months, but without precise values due the low coverage in time in our observations. No other observations programs for this star is know and it is needed actual observations for a better investigation of these variations.

As this star is bright (V~9.5), it is not needed to use large telescopes in the observation, being possible to execute this program in the BSM network. We estimate a needed singal/noise ratio of 300, to get a magnitude precision of 0.03 mag. This can be achieved with stacking 10 images of 30 seconds in V band, 20 images of 30 seconds in B band, 8 images of 30 seconds in R band and 7 images of 30 seconds in I band. The periodicity of observations can be twice a week, what will provide a good temporal coverage in the data. Optionally, the 0.6m MJUO can be used, with much smaller integration times.

References:
Campagnolo et. al, 2018: A&A accepted. arxiv: https://arxiv.org/abs/1712.01972
Mahner et. al, 2017: A&A, 608A, p. 124. ads: https://ui.adsabs.harvard.edu/#abs/2017A&A...608A.124M/abstract