[vsnet-newvar 1518] Re: HadV106: R CrB-like object??

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

Well, the limited number of archive images from the NOFS server (one E
plate and one F plate in the red) certainly shows it to be variable. 
The sole near-red N plate shows it to be overexposed at those
wavelengths.
The sole J plate is not sufficiently close enough in epoch to the F
plate to estimate even a crude colour index with confidence.

Again, this ~ 11.5p near "maximum" object is flagged as completely
overexposed in 2MASS. So no IR mag available, but this IR overexposure
(J, H, Ks upper limit is usually around mag 6) for a faint star in
itself suggests an infrared excess.

An estimated "Tycho Blue" mag of 13.3 is given for a year 1892 image in
AC2000.2.  The interpretation of the AC photographic magnitudes into a
Tycho blue system is not often very good, but the usual case is that the
BT magnitude estimated for the AC objects ends up being a magnitude or
two _too_ bright when the plate limit is approached (around BT 12 to
13).  So a ~13p mag from AC data gives a suggestion of a faint event at
that time too.

Caught in fade so frequently by what are in effect very large spaced
random samplings suggests that if it is an R CrB like object it is more
akin to the DY Per / Z UMi "type" than the R CrB / SU Tau "type".

Cheers

John


Taichi Kato wrote:
> 
> HadV106: R CrB-like object??
> 
>   YYYYMMDD(UT)   mag  observer
>   19981108.433  113p  (Katsumi Haseda)
>   19990322.808  115p  (Katsumi Haseda)
...

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