[vsnet-alert 14825] Re: PNV_J180645.2-360458

[Brian Skiff]

On Sat, 2012-08-04 at 11:24 +0900, Hiroyuki Maehara wrote:
> Shigehisa Fujikawa (Kagawa, Japan) reported his discovery of an unusual
> variable star (or possible nova?) in Sgr. 

>  The object is located at R.A. =  18h 06m 45.23s, Decl. = -36d 04' 58.5" 
> (equinox 2000.0; measured from 6 CCD images obtained by K. Itagaki with 
> 60cm telescope). There is a faint object in the 2MASS catalog
> (2MASS J18064523-3604583 Jmag=15.11) at this position.


     I note also that although the object is faint in 2MASS images,
it is prominent in WISE images at its three shorter mid-IR wavelengths,
but fades again at 22 microns.  The WISE coordinates match that of the
current outburst accurately, and thus it is not the star ~6" northeast
that is prominent in 2MASS images.  The WISE detection implies some
sort of warm dust is involved, consistent with the earlier brightening.
     If you can examine WISE images, look at a 5'x5' field, and notice
the planetary nebula about 2'.5 southeast (perhaps mag 18 in the 
visible), whose cool dust becomes very bright at the longer 
wavelengths.  Interesting comparison!


\Brian