Electronic Telegram No. 5352
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


(534625) 2014 UQ_224
     K. Ly, University of California at Los Angeles, reports that six archival
images taken on 2015 Nov. 17.61 and 18.54 UT with the 8.2-m Subaru telescope's
Hyper-Suprime Cam (HSC) on Mauna Kea indicate that the transneptunian object
(534625) is binary.  Three 110-s i-band exposures were taken on 2015 Nov. 17,
and three 130-s r-band exposures were taken on 2015 Nov. 18.  There were also
Subaru/HSC z-band images of (534625) taken on 2015 Nov. 16, but the resolution
was too low to discern the binary nature.  Later 30-s r-band Subaru/HSC
observations on 2016 Jan. 6 and 100-s z-band exposures taken on 2016 Nov. 24
did not show obvious signs of a companion.  W. M. Grundy (Lowell Observatory)
helped with measuring the binary system's separation and magnitude difference
in the 2015 Nov. 17 and 18 images.  The mean separation of the two components
on both dates was 0".4 +/- 0".1, corresponding to a projected separation
distance of 13000 +/- 3000 km.  The secondary component was 1.0 +/- 0.5 mag
fainter and was positioned at p.a. 305 +/- 15 deg from the primary.  The
following astrometry and magnitudes are for the center of light and the
combined fluxes.

     2015 UT             R.A. (2000) Decl.       Mag.
     Nov. 17.60752    4 32 24.10   +23 31 04.0   21.9
          18.53933    4 32 19.74   +23 30 55.7   22.0



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2024 February 20                 (CBET 5352)              Daniel W. E. Green