[vsnet-newvar 1770] TbrV0149 is likely GSC 8996 1474

[jg@jgws.freeisp.co.uk]

Vello's survey up to date has predominantly revealed long period
variables, primarily as a consequence of the observing regime.

The fact that the equipment used is red sensitive and that LPVs are
predominantly red is probably more incidental than anything, although it
does mean Vello is easily picking up some LPVs that would be quite a bit
fainter than surrounding stars visually.

Be that as it may, the lightcurve of TbrV0149 is consistent with that of
a red LPV of very roughly 300 ish days period.

GSC 8996 0455 is of B-V around 0 according to Tycho2 photometry, which
is not consistent with a red LPV.

Tycho2 photometry can be problematic, especially at the faint end, but
examination of NOFS archive plates show GSC 8996 0455 to be of similar
brightness on blue plates when compared to red, consistent with a
colourless object.

It is not then likely that this is a red LPV.  I am not familiar with
any blue variables that emulate red LPV lightcurves of a fairly regular
nature.

Examination of the same plate images showed GSC 8996 1474 to be quite
red, being faint on blue images relative to red images, and within a
colour plate set showing slight variability consistent with a low
amplitude red LPV.  There does not appear to be another candidate in the
area capable of being a red LPV.  GSC 8996 1474 is also an IRAS source,
which would also be consistent.

It is likely that TbrV0149 is GSC 8996 1474 due to its redness, IRAS
sourceness and slight variability, again all consistent with an LPV as
can just be seen from archive images.

Whether it is also NSV 19483, mentioned in a separate post, is another
matter entirely, as that object has identification problems in terms of
position and/or type all of its own.


John Greaves

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