RE: New technical note

["Albertson, Chris" <CAlbertson@primeadvantage.com>]

Sorry for the repeated message.  Blame it on crossed up mail.
It looks like I just sent about the same comment you had 
already answered.

It may be worth making a model that tries to predict the
number of transits we should expect to see.  It should
cover both the "real" universe to be observed and our
observation plan.  I suspect that details of our plan will
have large effects on the number of transits seen.  For
example do we look at 6 patches of sky for 4 hours a day
or 12 patches for 2 hours each day?

"Model" is a fancy word.  I think just a list of factors
that can be e-mailed would be good enough of maybe a
spreadsheet exported to CSV format.



> -----Original Message-----
> From: Michael Gutzwiller [mailto:deepsky@fuse.net]
> Sent: Monday, February 26, 2001 6:49 PM
> To: TASSList
> Subject: RE: New technical note
> 
> 
> The 1000 stars were definitely not selected at random.  First 
> they needed to
> be bright enough to do the spectral analysis.  Secondly I 
> believe they were
> selected as being "sun like".  So there might be some bias in 
> the results.
> Certainly red giants would be poor choices when looking for planetary
> transits.  M class dwarfs would yield deeper transits since 
> the star would
> be smaller but perhaps they might not form hot jupiters, the 
> jury is still
> out on how they form.
> 
> Finding the transit candidates by looking for periodic 
> behavior would be
> very difficult since they typically would spend only 3% of 
> their time in
> transit.  I believe the best approach is to identify candidates with a
> survey and use another telescope, like an LX200, to follow 
> the candidates
> for long periods of time to see if other tansits occur.
> 
> Mike G.
> 
> 
> -----Original Message-----
> From: Albertson, Chris [mailto:CAlbertson@primeadvantage.com]
> Sent: Monday, February 26, 2001 1:06 PM
> To: 'Michael Gutzwiller'; TASSList
> Subject: RE: New technical note
> 
> 
> 
> The fraction ".015", As you say is "Based on the catalog that shows
> 15 stars with planets of which at least one qualifies as a hot Jupiter
> and the statement on exoplanets.org that about 1000 stars have been
> searched."
> 
> Could it be that those 1000 stars were not selected at random?
> If so the number .015 would not apply to the general population of
> stars.
> 
> Transits are periodic.  About as "periodic" as it gets.  We should
> be able to take advantage of this.  If you detect parts of a transit
> on different periods it as good as getting multiple observations of
> the same transit.  The only way you could hope to do that would be to
> pick a few small fields and hit them every night.  Also and maybe more
> importantly, a periodic signal can be detected at a much lower signal
> to noise ratio.  We know the shape of the "dip" in the light curve
> and can possible use a convolution or something like it.  Given enough
> data points there are many signal processing tricks that would apply.
> We'd need a few years of observation of the same field.  Hopefully
> with cameras at different longitudes.
> 
> I am thinking about picking (say) 12 fields and following one of them
> two hours then switching to the next.  It would be good if some other
> TASS site picked up the field.
> 
> > -----Original Message-----
> > From: Michael Gutzwiller [mailto:deepsky@fuse.net]
> > Sent: Sunday, February 25, 2001 7:58 PM
> > To: TASSList
> > Subject: New technical note
> >
> >
> > I've created a new technical note outlining my ideas for 
> searching for
> > extrasolar planets with the Mark IV.  For now the technical 
> note is at
> > http://home.fuse.net/deepsky/tn74.htm until Michael moves it
> > to the main
> > TASS technical note area (thanks in advance Michael!)
> >
> > Please have a look and let me know what your reactions and
> > comments are.
> > The process won't be easy but some important contributions to
> > current topics
> > could be made by using the Mark IV.
> >
> >
> > Thanks,
> >
> > Mike G.
> >
> >
> >
> 
> 
>