J/A+A/704/A169 R band light curve of 288P/2006 VW139 (Waniak+, 2025)
Component-resolved light curve of the binary main-belt comet 288P/2006 VW139.
Waniak W., Drahus M.
<Astron. Astrophys. 704, A169 (2025)>
=2025A&A...704A.169W 2025A&A...704A.169W (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Photometry, CCD ; Optical
Keywords: minor planets, asteroids: individual: (300163) 2006 VW139 -
comets: individual: 288P/2006 VW139
Abstract:
Over half of the cometary nuclei and a part of the asteroids that have
been photographed so far by space missions or imaged by Doppler radar
techniques appear to be bilobate or contact binary systems. The latest
research on these objects shows that rotational fission and fragment
reconnection can lead to reconfiguration, creating the next generation
of bilobate bodies. In this context, Main-belt comet 288P, the only
known double object of this class with components of comparable
masses, appears to have successfully avoided reconfiguration or
disassociation into a dynamically unbound pair and has become a wide
asynchronous binary.
Our goal was to determine the physical parameters, such as sizes,
shapes, and rotation periods, of both components of 288P to understand
how this double asteroid formed and how it has evolved to obtain
today's very wide orbit. We also tried to confirm or deny the
existence of a third component in a tight pair with the larger, slowly
rotating fragment, as previously suggested.
We obtained a composite light curve of 288P by observing this object
with the Gemini South and Keck II telescopes working in tandem.
Through model analysis we separated this light curve into components,
one for each fragment. We found their sidereal rotation periods and
the most probable shapes and sizes. We analysed the angular momentum
and energy balances and compared actual values with that expected at
the moment of rotational splitting to check how much surplus has been
introduced into the system.
We determined the rotation periods of the components to be 15.86 hours
for the larger object A and 3.37 hour for the smaller fragment B.
Assuming a geometric albedo of 0.07 in the R photometric band, surface
and reflectance properties adequate for C-type asteroids and comets,
and considering A and B as prolate spheroids, we found that their
semi-axes a, b (where b<a) equal to 1.12, 0.69 and 0.67, 0.57km for
the larger and smaller components, respectively. The existence of a
third body in 288P cannot be definitely excluded but should be
considered as unlikely.
A plausible mechanism responsible for the origin of the binary
asteroid 288P is rotational fission of a bilobate progenitor spun up
by the Yarkovsky- O'Keefe-Radzievskii-Paddack mechanism or, more
likely, by sublimation-driven torque produced by an active region or
regions. It is almost certain that the sublimative activity of the
smaller fragment B is behind its relatively fast, completely
asynchronous rotation and the wide mutual orbit of the components.
Description:
Extra atmospheric magnitudes of Main-belt comet 288P in the Cousins R
band for 1.0 AU helio- and geocentric distances are presented. These
magnitudes are not corrected for the phase angle effect.
Part of the data was obtained with the DEIMOS instrument on Keck II in
the R photometric band, whereas some of the data were obtained with
the GMOS instrument on Gemini-South in the SDSS r' band and then
transferred to the R magnitudes.
object:
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Code Name Elem q e i H1
(d) (AU) (deg) (mag)
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288P P/2006 VW139 2459640.5 2.4369800 0.2011684 3.237843 16.92
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 32 444 Light curve of 288P in the R band
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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2- 9 F8.6 d Time UT time in fractions of a day starting from
0:0 UT on 21 May 2015 (1)
13- 19 F7.4 mag Rmag R magnitude
23- 28 F6.4 mag e_Rmag R magnitude error
32 A1 --- Note [DG] Instrument (2)
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Note (1): and corrected for the time of flight of light corresponding to the
object-observer distance.
Note (2): Instrument as follows:
D = DEIMOS on Keck II
G = GMOS on Gemini-South
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Acknowledgements:
Waclaw Waniak, waclaw.waniak(at)uj.edu.pl
(End) Patricia Vannier [CDS] 21-Nov-2025