RE: Atypical variable stars...

[Thomas Droege <tdroege2@earthlink.net>]

Hello Robert,

> In the cases I am thinking of "long term" might be anything
> from days to years.  The type of data that I am interested
> in might be similar to that one would encounter on the tail
> end of a supernova event.  I.e. one has an observed star that
> "fades to black" over some period.  It would differ from
> classical supernovas in that there would not be any increase
> in brightness associated with a supernova event at the
> beginning.

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.

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.

This means that those 2000 CDs should be a valuable data mine for anyone
who wants to write a different code to find all the measurements that are
good that are not found by the present software.   I think such an analysis
would allow tracking red variables for a much longer time.  I suppose that
this would also be true for any "super blue" stars, but I don't think there
are any stars where V is many mags brighter than I???

Tom Droege




> [Original Message]
> From: Robert J. Bradbury <bradbury@aeiveos.com>
> To: TASS <tass@listserv.wwa.com>
> Date: 8/24/2004 5:44:56 AM
> Subject: Atypical variable stars...
>
>
> I would like to ask the question of whether or not the
> TASS data reduction processes are capable of detecting
> what I would call a "long term variable star".
>
> In the cases I am thinking of "long term" might be anything
> from days to years.  The type of data that I am interested
> in might be similar to that one would encounter on the tail
> end of a supernova event.  I.e. one has an observed star that
> "fades to black" over some period.  It would differ from
> classical supernovas in that there would not be any increase
> in brightness associated with a supernova event at the
> beginning.
>
> The TASS efforts as far as I can determine are directed
> towards the identification of classical variable stars
> and perhaps supernovas (obviously a fair amount of high
> end astronomical resources are devoted to supernova surveys
> due to their impact on our current understanding of the
> structure of the universe).  It may be the case that
> current screens for variable stars in the TASS data
> would miss the types of objects that I am interested in
> (I don't know because I don't understand the data compression
> extraction process that TASS is using).
>
> The "long term variable star" which which may be of significant
> interest is one that is involved in the construction of a
> "Matrioshka Brain" [1].  Briefly one can view a "MBrain"
> as a Dyson shell supercomputer constructed by an
> advanced technological civilization (not far beyond
> our current level of technological development).  I have
> written a paper which discusses this process [2].  I am
> happy to accept criticisms or thoughts on this topic and
> how it may relate to TASS.
>
> While the term "Matrioshka Brains" may be unfamiliar to most --
> it (and variants) have been under discussion by a small group
> of well educated people for about a decade.  The concepts are
> based on Dyson Shells that go back more than 40 years.  It may be
> worth noting that these ideas are in the process of becoming
> mainstream as they are mentioned in Popular Science this month [3].
>
> I would leave it to the group to determine the relative value
> of detecting "yet another variable star" vs. detecting the
> first example of an extraterrestrial advanced technological
> civilization under development.  Mind you -- I do not believe
> that TASS data might yield conclusive evidence in that area
> but it could well provide clues that would lead to observational
> programs which could quite literally "shock the world".
>
> Robert
>
> 1. http://www.aeiveos.com/~bradbury/MatrioshkaBrains/index.html
> 2. http://www.aeiveos.com/~bradbury/MatrioshkaBrains/WSGD.html
> 3. http://www.popsci.com/popsci/science/article/0,12543,676265-1,00.html
>