[vsnet-chat 3516] Re: EO Eri ( NSV1710 ) - A Mira Variable

["Stan Walker" <astroman@voyager.co.nz>]

Peter,

I've just seen this note buried amongst screeds of others. Don't knock
Wenzel too much. All of these Miras with periods of 400+ days seem to be
unstable insofar as the period and shape of the light curve goes. R Cen is
perhaps the most stable. But BH Crucis is sometimes a double humped Mira,
sometimes single humped, and sometimes has a bump on the ascent/descent like
Cepheids around 10 days. All of this shows up in the pe measures although
not always clearly in the visual ones. So give it time - 10 years is a very
short baseline. I'd be interested in seeing what you've concluded - don't
the VSS measures go back before 1990?

Regards,
Stan

PS Thanks for the data on V803 Cen - it's now in outburst.

S

----- Original Message -----
From: Peter F Williams <pfwilliams@onaustralia.com.au>
To: vsnet-chat <vsnet-chat@kusastro.kyoto-u.ac.jp>
Sent: Monday, July 31, 2000 11:20 PM
Subject: [vsnet-chat 3512] EO Eri ( NSV1710 ) - A Mira Variable


> Hello All,
>
> I am currently drafting a brief paper on the Mira type variable EO Eri
> (NSV1710; IRC-20062; IRAS 04430-2356) covering observations obtained
during
> the interval 1990 November through 2000 March.
>
> These observations, by members of the VSS RASNZ, indicate this is a
typical
> Mira star of period 447.5 days and visual magnitude range 10.6 to fainter
> than 15.5.  At minimum, EO Eri has been shown to fade to a photographic
> magnitude near 18.
>
> An epoch for maximum brightness is : JD 2448597 + 447.5 days.
>
> Two types of maxima are evident: (1) bright maxima averaging magnitude
> 10.6, and (2) faint maxima peaking near magnitude 11.6, the latter being
> much broader at maximum and remaining near maximum brightness  for upto 8
> weeks.  There is, however, no evidence to suggest a double wave light
curve
> (such as seen with R Cen) as was suggested by Wenzel in IBVS3504 but the
> above period agrees well with that found by him.
>
> Based on the above elements, EO Eri should have reached maximum during the
> first week of July for those who work the morning sky.
>
> Regards
>
> Peter Williams
> Heathcote NSW
>
>
>

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