Re: HD 145913

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

Re: HD 145913

> Doh, my ISP filtered this message as spam.

   Did the ISP, as a whole, recognized this address as spam? ;-)

> 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?

   It depends on the nature of the noise.  If the noise is purely random
and frequency-independent, the Fourier spectrum should be that of a white
noise.  In many realistic cases, the things are not that simple, and
there is usually a time-dependent process in noise production.  It is
therefore difficult to distinguish a natural signal from a noise based
on the power spectrum only.  It would be worth mentioning that "random walk"
type noise (when stochastic noise is accumulative in time domain) produces
a power law-type power spectrum.

   Anyway, if I remember correctly, peculiar A-type stars (Am or Ap) are
equally abundant as normal A stars.  So you will have sufficient chance
to indeed catch low-amplitude variations in A-type stars.

Regards,
Taichi Kato