Electronic Telegram No. 5413
Central Bureau for Astronomical Telegrams
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(523764) 2014 WC_510
     A. Thirouin, Lowell Observatory; W. M. Grundy, Lowell Observatory; K. S.
Noll, Goddard Space Flight Center, NASA; and S. S. Sheppard, Carnegie
Institution for Science, report that the transneptunian object (523764) is a
nearly-equal-sized binary system based on images obtained with the Hubble
Space Telescope (HST).  The two components are well separated, and the
secondary is about 25-30 percent fainter than the primary.  The primary was
located at R.A. = 6h46m22s.7, Decl. = +3d07'04".8 (equinox J2000.0), and the
secondary at position end fugures 22s.7, 04".9 on 2024 Mar. 6.899 UT.  The
separation between the two components was about 0".12 at p.a. about 69.8 deg.
Based on a stellar occultation recorded in Dec. 2018, this TNO was reported as
a close binary by Leiva et al. (2020, Planetary Sci. J. 1:48) with a
separation of 0".016.  The satellite reported by Leiva et al. and the
satellite visible in these new HST images are likely the same object.
Therefore, the present authors conclude that the stellar occultation happened
when the two components were very close, inferring that this system is
undergoing or has already undergone a mutual-events season.


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2024 July 15                     (CBET 5413)              Daniel W. E. Green