[vsnet-chat 2862] (fwd) Red star analysis (Greaves)

[Taichi Kato <tkato>]

Date: Sat, 29 Apr 2000 10:33:43 +0000
From: JG <jgts@jgws.totalserve.co.uk>
Subject: Red Star Analysis : please forward to vsnet

For those in charge of large databases of visual observations for LPVs
that they are not sure what to do with I recommend you read the
following:-

http://vsnet.telf-ast.demon.co.uk/00042b.html

[the graphs appear to have suffered a bit on transferal to GIF and
somehow, even in the original, fig 1 was reproduced twice, causing the
loss of fig 2].

It was written a couple of years ago and some details would be
done/noted differently now, and others have been reinforced and
extended, but it shows that examination of phase stability in LPV visual
lightcurves can give quite rigorous results in cases where O-C cannot
go, and it is easier and quicker to implement and interpret than wavelet
analysis.

John Howarth's AMPSCAN procedure is a very powerful tool, and full
reference is given in the above.

I commend it to all who want to know how to get the most from their
years of visual LPV data.  A couple more papers written a year or two
ago are trickling through the system and should be out over the next
couple of months (the above is the second paper, but came out first!).
Later, a trio of short papers, penned a year ago, will show how acf of
ampscan data can be utilised to show tertiary timescales in LPVs [we
subsequently discovered that these were first noted 40 to 50 years ago
by people like Houk and Payne-Gaposchkin, but had been mostly forgotten
since], and how simultaneous measurement of phase stabilities in doubly
periodic SR stars can distinguish between continuous secondary periods
hidden by the scatter and _true_ pulsation mode switching.

Hope it's of some use to somebody.  There's plenty of good quality
visual data out there just waiting to be put to use.

Cheers

John

John Greaves
UK

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp