[vsnet-chat 5267] Re: [vsnet-gcvs 201] Re: theta Apodis

["Sebastian Otero" <varsao@fullzero.com.ar>]

Dear all:

Stan wrote:

> 14 UBV measures tend to
> suggest that the variation is from 5.0 to 5.8 at least. I did a
periodogram
> of this and found a main period of 98.8 days although the data didn't fit
> this all too well. I see the GCVS gave 119 days and a range of 6.4-8.6p.

>We concluded that it probably had
> two periods which beat together.

And Peter wrote:

> Theta Aps, appearing in Publications No24 of the VSS RASNZ (April 2000)
> is a paper I prepared based on 553 visual observations between 1959 and
> 1999 from the VSS data base. These indicated a mean visual range of 5.6 to
> 6.4 and extremes of 5.2 to 6.8.  An average period of 115.93 days was
> found.  Derived elements for maximum are JD 2449558 +/- 115.93 days.

It sounds interesting that my current deduced period (from visual inspection
fo the lightcurve only) is exactly at the middle of both periods Peter and
Stan quoted:

Peter: 115.9 days
Stan:  98.8 days
Mine: 107 days

From the recent lightcurve is obvious that the ephemeris provided by Peter
don't fit with the observed.
Maybe the period has been shortening (119 - 116 - 107...)
I'll download Hipparcos data and read the papers mentioned by Brian that
must be very interesting.


> I'd imagine that Sebastian has measures during an interval when the beat
> period is low, or has reinforced one or two bright maxima. I didn't see
him
> quote a period and haven't had time to get onto the website.

However I don't find any irregularity or traces of beating between two
periods in the shape of the lightcurve. The beating effect is tremendously
evident in the L2 Puppis case mentiones by Stan.
(See http://ar.geocities.com/varsao/Curva_L2_Pup.htm  ) and in other cases
like R Doradus (http://ar.geocities.com/varsao/Curva_R_Dor.htm  ) and S
Leporis
(http://ar.geocities.com/varsao/Curva_S_Lep.htm  ).

As mentioned in the past these red variables are very interesting and make
up a somewhat overlooked discussion topic.
I can't keep my eyes off of the changong period miras like BH Cru and R Cen
for example !!!

Regards,
Sebastian.


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