[vsnet-chat 3681] Re: V Boo

["Ondrej Pejcha" <opejcha@volny.cz>]

I have added further simulations to my webpage:

http://vsnet.volny.cz/opejcha/vboo/vboosim1.gif
Hypothetic lightcurve with parameters same as mentioned in
vsnet-chat 3678.

http://vsnet.volny.cz/opejcha/vboo/vboosim2.gif
Hypothetic lightcurve with parameters: two periods 257.8 and
137 days. Longer period decreases semi-amplitude from 1.3 to
0.3 mag (intrisically, not adding close component).
Semi-amplitude of the shorter period is constant at 0.2 mag.

http://vsnet.volny.cz/opejcha/vboo/vboofou1.gif
Profile of the main peak in Fourier spectrum of the previous
hypothetic lightcurve (vboosim2.gif).

http://vsnet.volny.cz/opejcha/vboo/vboofou2.gif and
.../vboofou3.gif
Fourier spectrum after removing main period (DFT found same
value as defined: 257.8 d). Note the two very prominent
peaks at place of the removed period. Their amplitudes are
close to ratio 0.8:0.3 that John mentioned in chat 3678. The
higher of them has value 259.2 days.

http://vsnet.volny.cz/opejcha/vboo/vboofou4.gif
Fourier spectrum after removing higher from the two peaks
around 260 days (both disappeared). Evident is only
secondary period.

If you do the same procedure with data consisting of three
periods (two of them very close) you get the same result. It
is evident that DFT can't discrimine between amplitude
decrease from beat up effect and some sort of amplitude
decrease caused by other reasons. The same is with V Boo. If
the amplitude of V Boo rises in next decades, we can speak
about beat up effect (although not necessary). Only further
observations will show... (I'm starting to hate this
sentence).

I'm not familiar with pulsational theory, but can recent
theory handle such close periods? Would it requires very
high pulsational modes?

Best regards,

Ondrej Pejcha

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