[vsnet-survey 13] (fwd) a couple of ASAS curious duos... (Greaves)

[Taichi Kato <tkato>]

(fwd) a couple of ASAS curious duos... (Greaves)

Date: Sun, 14 May 2000 13:02:11 +0000
From: JG <jgts@jgws.totalserve.co.uk>
Subject: a couple of ASAS curious duos...

[Possibly of interest to vs-survey]

The following ASAS periodic list "duos", especially their lightcurves and
v.similar periods as per the gallery,

http://archive.princeton.edu/cgi-asas/asas_galery

should be of special interest to folk.

ASAS 125420-6356.1 & ASAS 125427-6356.1 [44" apart]

where the second one is the "rapid flicker undetermined var" RY Cru.

the other example is 

ASAS 180445-2243.8 & ASAS 180449-2243.9 [1.1' apart]

where the second one is the delta Cepheid AV Sgr.

[clue, in each case the former lightcurve is a "scattered" reflection of
the latter]

There may be other cases.


Meanwhile, merging ASAS 065304-0001.9 available I data with available
tenxcat smaller but still useful I data for TASS_J065304.2-000152 [one is
also the other] seems to nicely show this object to be an SRa star of about
345 day period.


On the "multi-epoch" front, some general guide-lines/formulae from those
more experienced re photometric transformations may come in useful, at
least for periodicity work.  Even the use of B-V values derived via the
"Kato" transformation formula from USNO red and blue mags, to allow FASTT R
or similar to be approximately transformed with respect to ASAS &/or TASS I
band data, could be useful.

I know it wouldn't be too meaningful/accurate photometrically speaking, but
at least with respect to long period variables [maybe only 10 days upwards,
but definitely for 100+ days] DFT can still give good results [even with
ropey visual data!], as can even O-C for that matter given enough
maxima/minima.


Meanwhile, and as often seems to be the case, previously invariant Carbon
Stars appear to make up a not insignificant proportion of the ASAS newbies
[I'm sure use of the I band helps here!].

Cheers

John

John Greaves
UK

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