RE: Atypical variable stars...

[Thomas Droege <tdroege2@earthlink.net>]

Robert,

"So one would want to identify cases where V is going down at some
rate where I is decreasing at a slower rate."

You will find a lot of these in the tass data base.  I have seend many of
these when I have been looking at the data.  No doubt also ASAS sees these.
So you probably have hundreds of candidates to look at.

Go for it.

Tom Droege
 


> [Original Message]
> From: Robert J. Bradbury <bradbury@aeiveos.com>
> To: Thomas Droege <tdroege2@earthlink.net>
> Cc: tass <tass@listserv.wwa.com>
> Date: 8/24/2004 12:50:23 PM
> Subject: RE: Atypical variable stars...
>
>
> On Tue, 24 Aug 2004, Thomas Droege wrote:
>
> > This brings up an interesting problem with the TASS data.  The present
> > software requires simultaneous hits in V and I to keep an measurement.
> > This throws out about 80% of the data.  OK, I have set the cut low
because
> > of this, but still we probably only put half the possible data in the
data
> > base.
>
> In particular it would seem to remove the type of trend that MBrain
> development would represent.  In that case V would diminish quite
> a bit faster than I.  (This is because as MBrain development takes
> place the star still radiates the energy but it gets shifted further
> and further from the visible into the infrared region (even far
> beyond I into J, K, L, etc.).
>
> So one would want to identify cases where V is going down at some
> rate where I is decreasing at a slower rate.
>
> As mentioned -- these trends may vary from rates that involve days
> to years (ultimately millions of years -- but this involves very
> old/cold MBrains that are probably invisible in both the V/I regions).
>
> > Long period stars tend to be red.  This means the V component is
typically
> > 2-4 mags less than the I component.  As the star dims, when the V
component
> > drops below 13 or so we begin to have losses, and most data is lost by
V of
> > 15.   But the I component is still quite bright for a typical red long
> > period star.  Too bad, it is lost by our present analysis.
>
> Understood.  But the question is whether the *rate* of decline in V
> is significantly different from the rate of decline in I.
>
> If one is shifting the blackbody radiation curve of a star you
> can have a decline in V but it has to be compensated for by
> a maintenance or increase in I.  So those stars that TASS
> "drops" because they decrease in V should be sub-selected for
> those that "never" come back.  If these still have a detectable
> I component they may be significant.  Ultimately one would like
> to match this with the Hipparcos, 2MASS or IRAS data to determine
> if the star is excessively bright (or brighter) in with respect to
> IR wavelengths.
>
> > ...but I don't think there are any stars where V is many mags
> > brighter than I???
>
> Not normally as far as I know *but* there are scenarios I can
> imagine where one would attempt to heat up a star for various
> energy production purposes (if you can surround a star with
> solar collectors you can obviously reflect all the energy
> back onto the star with some interesting effects most likely).
> There are MBrain applications where one might want to produce
> the greatest amount of energy in the shortest period of time
> in which case stellar super-heating may be a reasonable engineering
> strategy.  There are also strategies along this line that I
> could envision might be used for shifting the nucleosynthesis
> reactions in the surface of the star to produce heavier elements
> (which get blown off into space and subsequently collected).
>
> So I would suggest that there is merit in noticing any data
> that varies from the "norm" to any significant degree.
>
> Robert
>
>