Characterisation of stochastic low-frequency variability in 50 massive stars

The advent of photometric space telescopes has revealed that stochastic low-frequency (SLF) variability is a common type of variability found in massive stars. Here we analyse the TESS data for 50 massive stars showing SLF variability; 49 of which are found across six different Cygnus OB associations and one from the Small Magellanic Cloud (SMC). The SLF signal is characterised using two different methods and compared to a sample of 53 O- and B-type stars which have previously been studied in the literature. We find that SLF variability of the lower metallicity SMC star shows similar characteristics as the 102 Galactic stars. Furthermore, we find a significant correlation between the spectroscopic luminosity of our sample of 49 Cygnus OB stars and the amplitudes and slopes of their SLF variability, while no similar significant correlation is found for the characteristic frequency.