re New Stars

[jg <jg@jgws.freeisp.co.uk>]

I've had a quick look at some catalogue bumf for Patrick's short period
suggestions to Michael K.'s enquiry re new star candidates.  From such
you can throw together some circumstantial evidence with respect to
their potential variability, which may, or may not, pan out.  Mostly
addresses the previously unknown objects.


GSC00380-00247   third object in list at
http://a188-l009.rit.edu/tass/data/ds23/tom_suspect.html . As it is G5
and a bright xray source, I'd say it was likely an eclipser.

GSC00410-02795   probably early enough spectral type to be a potential
dSct and not too early to be a RR Lyr (from B-V), but it is a faint xray
source.  Quick look at a dozen randomly picked dSct stars shows none as
xray sources.  Random look at half a dozen of the brighter RR Lyr stars
shows only one as a faint xray source. EW stars are often faint xray
sources.


HD 153586       a bit bright for an unknown RR Lyr star (well, you never
know), and the A2 spectral type fits nicely for a delta Scutid, but
again a faint xray source, circumstantially pointing towards EW: rather
than dSct.


HD 155229       apparent brightness and spectral type (8.1 V and F0
respectively) good for a possible delta Scutid. RR Lyr not precluded,
but very bright for unknown regular variability of about half a mag
amplitude, or even possibly just too bright for a field RR Lyr, full
stop. _NOT_ a known xray source.  In the above mentioned random sampling
of dSct and RR Lyr stars the majority showed themselves to be infrared
sources: this is a faint IRAS source.  Circumstantial evidence from
catalogue bumph suggests delta Scutid most likely of three variability
classes mentioned.


Of course, Michael (K), somebody's gotta look at 'em to see what the
truth is ;^) , but you seemed to want some clues as to what was and what
wasn't a potential EW etc.

Cheers

John G.


Note on NSV 7901 : have seen cases before where stars noted as slow
irregular objects in NSV have been later shown to be short period
variables.  This usually stems from the discovery images being a handful
of photographic plates well spaced in time, where the types are
indistinguishably uncertain.  Later data, eg ASAS survey, has shown even
"slow irregular" GCVS stars to be short period variables.  NSV 7901 has
B-V around +0.33 and is a faint xray source (EB??)...