[vsnet-chat 4832] Re: V412 Cen, NSV 6507

["Sebastian Otero" <varsao@fullzero.com.ar>]

Dear Fraser and friends:

> V412 Cen is classified SR+E? with a range of 5.1 to 6.6, so this might
> be an eclipse in progress.

There was a confussion in your message between V412 Cen and V744 Cen
The range and classification you mentioned corresponds to V744 Centauri not
to V412 Centauri.
Furhtermore, I don't know where that E-type classification comes from
(help?).

V412 Centauri is a red variable (M3Iab/Ib) with a small range. Actually I
have never seen it anywhere outside the 7.0 and 7.4 range.
BUT the amplitude is somewhat greater, what happens is that this is a visual
binary and we are observing (through binoculars) the combined brightness of
the pair.
The duplicity is apparent in the image through my 7x50's although I can't
separte the stars. The companion is a B7III star of magnitude 8.8. The
bluish tint of the companion added to the red color (B-V 1.7) of the
variable makes it an odd-looking star.


> V412 Cen and NSV 6507 are both unusually dim this evening:
>
> CENV412  20010909.469  74
> NSV6507  20010909.471  83


So 7.4 is normal for V412 Cen.

And NSV 6507 is at minimum and in a period of low activity but 7.7 to me.
This is a carbon star so its deep red color near the limitting magnitude of
a pair of binoculrs makes it a good candidate for this kind of discrepance.
Remember red stars disappear (cones not estimulated...) while approaching
the instrumental limitting magnitude while bluer stars keeps being detected
by the rods.

Cheers,
Sebastian.


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