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Re: HD 145913
Doh, my ISP filtered this message as spam. I've fixed that now. I want
to thank Dr. Kato for this information. (I'm not hip to the "Kato-san"
cultural references, so please educate me if I refer to people
So assuming for a second that the flicker I recorded is not a result of
systematic problems on my end, it is common that a period would be
apparent or can nearly random noise produce things that look like
periods in Fourier analysis?
I will get Kato et al. (2002) PASJ 54, 1033.
On Thursday, May 8, 2003, at 09:43 PM, Taichi Kato wrote:
> 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
> This star has a good HIPPARCOS parallax measurement. At this
> the absolute visual magnitude is about +1.9, consistent with the
> main-sequence value of the corresponding spectrum. So this is not a
>> "Virtually all CVs flicker erratically on timescales of 1-3 minutes,
>> 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
>> 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
> 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.
> Taichi Kato