RE: New technical note

["Michael Gutzwiller" <deepsky@fuse.net>]

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.
>
>
>