[vsnet-newvar 719] Re: [vsnet-chat 3899] re Re: [vsnet-id 325] Info on a LMC star

[Taichi Kato <tkato>]

Re: [vsnet-chat 3899] re Re: [vsnet-id 325] Info on a LMC star

> I've just looked at the online ASAS lightcurve for this object, and
> although there seems to be quite a large amplitude of variation, a bright
> hypergiant A star varying by nearly half a magnitude in the I band in about
> a year sounds a bit weird to me, and the semi-cyclic nature of the changes
> is suspiscious... ...then again I've no I band info on hypergiant stars
> like rho Cas or similar for comparison.

    The star is (close to B) A hypergiant (likely a massive star), probably
unlike F-G supergiants.  The star may more resemble luminous blue variables.

> BUT, ASAS stuff in the LMC has fallen down before due to being fooled by
> duplicity induced variability caused by variant seeing etc at different
> times, because of the crowded fields.

    ASAS has found variability in several other B-A hypergiants, some of
which are sufficiently isolated to be contaminated by nearby stars.
Other correct 'rediscoveries' of many already known LMC variables in crowded
fields seem to suggest ASAS has picked up mostly correct variables.

    Anyway, this star should to be at best avoided as a comparison star.

Regards,
Taichi Kato

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