[Iaude] CBET 4596: 20190109 : (7393) LUGINBUHL

quai at eps.harvard.edu quai at eps.harvard.edu
Tue Jan 8 18:36:38 EST 2019

                                                  Electronic Telegram No. 4596
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

     B. D. Warner, Center for Solar System Studies, Landers, CA, USA; and
B. A. Skiff, Lowell Observatory, report that photometric observations obtained
with 0.20-m telescope at Landers from 2018 Dec. 4-2019 Jan. 3 reveal that the
Flora-family minor planet (7393) is a binary system with an orbital period of
39.422 +/- 0.003 hr.  The primary shows a period of 2.68763 +/- 0.00005 hr
and has a maximum light-curve amplitude of 0.10 mag at solar phase angles
18.3-6.0 degrees.  The shape and amplitude of the light curve suggest that
the primary shape is nearly spheroidal, although a minor brightening (0.04
mag) in the light curve at one of the minima may indicate a feature (e.g.,
flat area).  Mutual eclipse/occultation events that are 0.16 magnitude deep
indicate a lower limit on the secondary-to-primary mean diameter ratio of
0.40 +/- 0.03.  The light curve of the satellite outside of the events has an
amplitude of 0.09 mag.  After accounting for dilution of the secondary light
curve by the primary, the upper limit for the satellite elongation, a/b, is
1.6/1.0.  Observations by Skiff in 2011 with a 0.78-m telescope showed trends
on Oct. 8 and Nov. 17 that closely matched those from the denser data set in
2018.  There were insufficient data to find the purported satellite in 2011.
However, those observations, combined with others planned for 2019 Jan. and
Feb., may allow a more accurate model of the system.

NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2019 CBAT
2019 January 9                   (CBET 4596)              Daniel W. E. Green

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