[vsnet-j 398] Re: [vsnet-alert 5493] Possible Nova in Pup

[Gianluca Masi <gianmasi@fr.flashnet.it>]

Dear Colleagues,
using an image kindly provided by M. Uemura (Kyoto University) I performed astrometry on
this nova candidate, getting the following results:

R.A.:  07h 37m 56.91s; Decl.: -25d 56' 59.0" (J2000.0)
10 reference stars from USNO A2.0. Mean residuals: 0.22"

USNO A2.0 reports the star A0600.06937901 at 

R.A.: 07h 37m 56.88s; Decl.: -25d 56' 59.1" (J2000.0)

m(R)=13.2; B-V=0.6 mag.


Confronting these two positions, the two objects are about 0.5" apart. So, A0600.06937901
actually has good probabilities to be the real progenitor (if this is a nova).

Regards,
Gianluca Masi



Taichi Kato wrote:
> 
> Possible Nova in Pup
> 
>     The accurate position provided by H. Abe agrees the position of a 14-th
> mag USNO star within 1-2 arcsec.  If this star is indeed the progenitor
> of the erupting object, the color from the comparison between the visual
> and 2MASS magnitudes becomes V-J = +2.  The color is not particularly red
> in this field.  Even assuming that the object is not significantly
> reddened, the color is still bluer than most of symbiotic stars, which
> have V-J colors of +3 to +5 or even larger.  If the object is a nova, the
> color suggests either a) usual cataclysmic variable with moderate reddening
> or b) cataclysmic-type binary with a relatively evolved secondary.
> [e.g. U Sco (Porb=1.2d) has a V-J color of +1.5].
> 
> Regards,
> Taichi Kato

-- 
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