[vsnet-alert 22096] Re: ASASSN-18iq

[Brian Skiff]

On Fri, 2018-04-20 at 13:09 -0500, Keisuke Isogai wrote:
> ASASSN-18iq
> 
>      Large outburst amplitude of 6.5 mag. SDSS colors (u=20.11, g=20.38, r=20.36,
> i=20.60, z=20.21) suggest a short orbital period. Note that the SDSS source is 2.1"
> away. CRTS data has not shown any outbursts.
> 
> ASASSN-18iq         -------     13:42:41.08     7:9:10.9  2018-04-19.44     14.04     SDSS     DSS     VIZIER     -------  CV candidate, matches to SDSS g=20.4, g>18.4 on 2018-04-16.26, V=14.0 on 2018-04-19.45, g=13.9 on 2018-04-20.28.

     Probably the ASASSN coordinates are skewed by two 
neighboring objects (a galaxy and a red star) due to the
small image scale of the survey.  Some good quality astrometry
collected from VizieR for the blue object is shown below.


epoch         RA  (J2000)  Dec       source
1950.298   13 42 41.37 +07 09 10.4   APM/POSS-I
1993.359   13 42 41.25 +07 09 10.7   GSC-2.3
2003.248   13 42 41.23 +07 09 10.4   SDSS DR7
2010.236   13 42 41.22 +07 09 10.3   UKIDSS DR9
2012.354   13 42 41.20 +07 09 10.3   Pan-STARRS


...suggesting slight proper motion nearly due west.
It is bright in GALEX far-uv, which gives J2000 coordinates:
13 42 41.23 +07 09 09.8.  The identification is thus unambiguous.
Next week, of course, we will presumably have a GAIA2 position, 
proper-motion, and parallax!


\Brian