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Re: HD 145913 > I seriously doubt it is a CV, with a quiescent magnitude of ~7.7, > since that would imply naked eye visibility if it ever went into > outburst. A5 is also quite red if we were dealing with a run-of-the-mill > CV. This star has a good HIPPARCOS parallax measurement. At this distance, the absolute visual magnitude is about +1.9, consistent with the main-sequence value of the corresponding spectrum. So this is not a CV. > "Virtually all CVs flicker erratically on timescales of 1-3 minutes, so > if your time resolution is much worse than ~40 s, you become blind to > this and it appears merely as unwanted noise (which can be quite large, > even ~0.2 mag)." Please remind that CV flickering has a power-law type time-variation (see e.g. Kato et al. (2002) PASJ 54, 1033 and references therein). This means (to a certain limit) the amplitude of variation becomes larger at longer time scales, and flickering is present at any sampling rate. (It would be interesting to see integrated light curve of artificially produced power law-type noise component). If there is a typical time scale, such a phenomenon is usually called quasi-periodic oscillations (QPOs) rather than simple flickering. Regards, Taichi Kato
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