Re: HD 189735

[Tom Droege <tdroege2@earthlink.net>]

I have measurements for 7 nights in September so far for this star.  One 
night is a 2 hour 48 pair run, the rest are 5 pair 15 minute runs.

Since I continue to take data I will not send it until someone really wants 
it.  Last night I caught a .3 or so mag dip.  I don't think it was a cloud 
or some artifact, but always possible.

Tom Droege

At 08:39 AM 9/10/02 -0500, you wrote:
>300.2996279     7.981603488
>
>aka
>
>20:01:11.91 +07:58:53.77
>
>
>On Tuesday, September 10, 2002, at 08:34  AM, Tom Droege wrote:
>
>>I should have more data on this one.  If someone will remind me of the 
>>decimal RA and Dec. I will look.
>>
>>Tom Droege
>>
>>At 10:29 AM 9/10/02 +0000, you wrote:
>>
>>>Michael and each
>>>
>>>I'd been looking at this one.
>>>
>>>The TASS data says it's an RS CVn variable caught at one secondary
>>>minimum and also with the maximal wave sampled too over several
>>>different nights.  The eclipse gets bluer, so it is secondary.  Primary
>>>eclipse may end up being as much as a mag.
>>>
>>>You are a long way off folding the current data into anything.  RS CVn
>>>light curves need serious and complete sampling, and can vary over time
>>>for various reasons (though more usually over the longer term) so
>>>folding isn't entirely safe.
>>>
>>>
>>>Probably ought to check with Dirk re nature (B-V may be a bit too
>>>"early" for RS CVn identification) and import: I believe RS CVn objects
>>>are not that common.  Period is gonna be a day or more, with a lot more
>>>also being possible.  Could be a significant find and worthy of a
>>>multi-observer campaign.  A good light curve gives rotation rate of
>>>secondary star as well as orbital period, though the vast majority of
>>>these stars are synchronous (or "pseudosynchronous" if the orbit is
>>>elliptical), so there should be could be no difference twixt the two.
>>>Showing whether object is asynchronous or not is an important part of
>>>collecting the light curve.  Collecting lightcurves at times over many
>>>years allows solar-type cycle to be assessed.  A good lifetime project
>>>one.
>>>
>>>Strangely no hint of xray source.  As you say, not previously known.
>>>
>>>Cheers
>>>
>>>John
>>