[IAUC] CBET 2402: 20100806 : (8026) 1991 JA_1

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                                                  Electronic Telegram No. 2402
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
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(8026) 1991 JA_1
     B. D. Warner, Palmer Divide Observatory and MoreData, Colorado Springs,
CO, U.S.A.; and Alan W. Harris, MoreData, La Canada, CA, report that
photometric observations obtained during July 11-17 reveal that minor planet
(8026) may be an unusual binary system.  There is a well-defined period of
2.300 +/- 0.001 hr and amplitude of 0.12 mag, typical of many asynchronous
binary systems.  They find another period of about 320 hr with an amplitude
(A) of about 0.40 mag, distinctly atypical of such systems.
     This system may represent a new type of binary system -- where the
primary has a very long period and a satellite with a short period -- that is
not tidally locked to the orbital period.  Similar traits were discovered for
minor planet (218144) 2002 RL_66 (Warner et al. 2010, Minor Planet Bulletin
37, 109-111), which had a primary period of 588 hr (A = 0.25 mag) and secondary
period of 2.49 hr (A = 0.04 mag).  Neither system reveals an orbit period
through mutual eclipse/occultation events, suggesting that the orbit period
may be very long and the component separation large.
     The authors request additional observations of (8026), including adaptive-
optic observations if possible, since there is a possibility of this being a
widely-separated pair.  Photometric lightcurve data will need to be well-
calibrated on an internal (if not standard) photometric system in order to
link night-to-night brightness levels.  The authors also ask any observers who
wish to participate to contact them (via brian en MinorPlanetObserver.com) to
arrange for coordination of observation and combined analysis of results.


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2010 August 6                    (CBET 2402)              Daniel W. E. Green