[vsnet-alert 16407] (no) ASASSN-13cy

[Denis Denisenko]

First I thought this object is a ghost image from the nearby 6.0m star
HR 534, but after going to Minor Planet Checker I am almost sure it
was a fast moving asteroid:

The following objects, brighter than V = 20.0, were found in the
15.0-arcminute region around R.A. = 01 50 37.6, Decl. = +11 01 32.0
(J2000.0) on 2013 09 14.43 UT:
(329437) 2002 OA22       01 50 32.9 +11 02 26  15.7   1.2W   0.9N    86+   160-

That was for geocenter (MPC code 500). For F65 (Haleakala-Faulkes
Telescope North) I am getting yet a better match:

(329437) 2002 OA22       01 50 36.7 +11 02 06  15.7   0.2W   0.6N    67+   158-

Note the parallax and fast motion of the asteroid. Object is at 0.08
AU distance from the Earth, equatorial parallax is 110". Time is
rounded to 0.01d in MPChecker, that's 14.4 minutes or 1/4 of an hour.
And this Near-Earth Object will travel 15"E and 40"S in 0.25 hr, which
is almost exactly the observed offset 0.2' and 0.6'.

Denis Denisenko

On Sun, Sep 15, 2013 at 4:14 AM, Taichi Kato
<tkato at kusastro.kyoto-u.ac.jp> wrote:
> ASASSN-13cy and ASASSN-13cz
>
>    These two objects deserve further time-series photometry.
>
> ASASSN-13cy     01:50:37.6     +11:01:32.0       2013-09-14.43    15.68
>    high-amplitude.  No object in SDSS.  No past outburst in CRTS.