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From: "Sebastian Otero" <varsao@fullzero.com.ar>
Date: Thu, 15 May 2003 01:20:27 -0300
Subject: [vsnet-chat 6335] AI CMi very bright
ASAS-3 data brings a confirmation of my observation of the post-AGB star AI
CMi in a **very** bright maximum: It was at V= 7.86 on May 10.
Lightcurves and comments on this one at:
http://ar.geocities.com/varsao/Curva_AI_CMi.htm
Regards,
Sebastian.
Date: Wed, 14 May 2003 21:49:36 -0700 (MST)
From: Brian Skiff <Brian.Skiff@lowell.edu>
Subject: [vsnet-chat 6336] Re: AI CMi very bright
>> AI CMi in a **very** bright maximum: It was at V= 7.86 on May 10.
I note that the GCVS v4.1 shows photo-blue maximum of 8.8, and given
that the star has B-V ~1.5, and thus maximum of V ~7.3, it seems as though
it would have to be above V=7.0 (at least) to be considered out of range.
Also, the TASS MkIII photometry shows mean V=8.23 with rms scatter of 0.26,
so it's not even 1-sigma above the mean of the MkIII data.
This looks something like an RV Tauri star to me.
\Brian
From: "Sebastian Otero" <varsao@fullzero.com.ar>
Date: Thu, 15 May 2003 02:14:07 -0300
Subject: [vsnet-chat 6339] Re: AI CMi very bright
> I note that the GCVS v4.1 shows photo-blue maximum of 8.8, and given
> that the star has B-V ~1.5, and thus maximum of V ~7.3, it seems as though
> it would have to be above V=7.0 (at least) to be considered out of range.
> Also, the TASS MkIII photometry shows mean V=8.23 with rms scatter of
0.26,
> so it's not even 1-sigma above the mean of the MkIII data.
> This looks something like an RV Tauri star to me.
>
> \Brian
It's bluer at maximum and fainter at minimum. The "p" range on the GCVS is
8.8 - 10.6
B-V at maximum is ~1.4 and at minimu ~1.7.
This would translate to V= 7.4-8.9
However, the star has usually been as faint as 9.5.
These "p" values generally don't agree with B-V transformations. It happens
a lot with miras and SR stars in the South that when observed visually look
totally different to what one might expect...
For instance, V798 Cen is catalogued as varying in p from 8.7 to 9.3.
With a B-V of 1.5 or redder, the star should vary between 7.2 and 7.7 or
7.8. But it is generally at V= 8.0, changing from 7.5 to 8.5.
In the AI CMi's case, deep minima last less than the relatively bright state
and the Mark III data consist in too few observations to establish a mean
magnitude.
In any case, I can not find any record that show this star brighter than now
in V.
And this is fun! ;-)
Sebastian.
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