Electronic Telegram No. 5562
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


(33956) 2000 NN_3
     T. Swift (Davis, CA, USA; a member of the International Occultation
Timing Association) reports the discovery of an apparent satellite of the
minor planet (33956) based on the occultation of the star TYC 6854-01090-1
(which has catalogued Gaia magnitudes G = 10.4 and R =10.0) on 2025 May 2.2635
UT.  The observation was carried out from Dunnigan, CA, using a 20-cm Schmidt-
Cassegrain telescope (+ Watec 910HX video camera with GPS-based video frame
time-stamps).  The light curve is available at the following website URL:
http://www.cbat.eps.harvard.edu/iau/cbet/005500/CBET5562_Fig1.png; a sky-plane
configuration diagram showing the observed occultation chord is posted at URL
http://www.cbat.eps.harvard.edu/iau/cbet/005500/CBET5562_Fig2.png.  The light
flux dropped below the level of comparison star TYC 0340-00799-1 (magnitudes
G = 11.7, R = 11.2), to the limiting magnitude of the recording (approximately
G = 13.3, R = 12.8), ruling out the possibility that a double-star occultation
produced the consecutive occultation events.  In Figure 1, the main body is
drawn with the NEOWISE-catalogue volume's equivalent diameter 6.8 +/-0.8 km,
with the length of the longer occultation chord being consistent with that
diameter.  The presumed satellite is represented as having a diameter of 2.8
km, matching the length of the shorter chord.  The separation of the presumed
satellite from the main body is 0".0098 in p.a. 107 degrees, with a sky-plane
separation of 14.3 km.  The separation of the two light drops is too large
to be explained by an occultation by the two ends of an elongate body having
a size consistent with the NEOWISE diameter.  D. Herald, Trans-Tasman
Occultation Alliance (TTOA) and D. Gault (TTOA) aided in the analysis.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2025 CBAT
2025 June 6                      (CBET 5562)              Daniel W. E. Green