The National Research Council recently released the Solar System
Exploration Decadal Survey ``New Frontiers in the Solar System: An
Integrated Exploration Strategy''. The Survey reviews the current
state of planetary science and exploration, and makes recommendations
for investments in ground-based and space flight research for the next
decade, 2003-2013. The Kuiper belt figures prominently throughout the
report. Of particular interest to readers of this newsletter is the
Survey's very strong support for a Kuiper Belt-Pluto Explorer mission,
which is given the highest priority recommendation for its class (medium
cost Solar System Flight Missions). The report also recommends support
for ground-based telescope projects, such as the Large-aperture Synoptic
Survey Telescope (LSST) and the Giant Segmented Mirror Telescope (GSMT),
explicitly including Kuiper belt studies as a major science driver. The
report can be ordered at http://www.nationalacademies.org/ssb/
and the full text of the report can be obtained in three PDF files at
http://www.aas.org/~dps/decadal/
The ``Pluto Portal'' is now available at:
http://www.boulder.swri.edu/plutoportal/
And yet more Pluto news: the Pluto occultation observing campaign
was successful in making detections during the July 20 and August 21
events. Preliminary results show that Pluto's atmosphere is cooling
and going though other global changes. See:
http://www.spaceref.com/news/viewpr.html?pid=9033
http://www.eso.org/outreach/press-rel/pr-2002/phot-21-02.html
http://despa.obspm.fr/~sicardy/pluton/results.html
Followup HST observations by Noll et al. have confirmed that 1997 CQ29
is, indeed, a binary. Original images on the WF3 CCD, only showed
possible elongation of the object; these new observations with the PC
CCD clearly resolve the components, which have a separation of 0.33
arcsec and confirmed binary motion.
IAUC 7959: http://cfa-www.harvard.edu/iauc/07900/07959.html
Similarly, Keck observations by Romanishin et al. confirm the binarity
of 2000 CF105:
IAUC 7962: http://cfa-www.harvard.edu/iauc/07900/07962.html
There were 3 new TNO discoveries announced since the last issue of the Distant EKOs Newsletter:
2002 AW197, 2002 KW14, 2002 KX14
and 3 new Centaur/SDO discoveries.
2002 KY14, 2002 JR146, 2002 PN34
Reclassified objects:
2002 GP32 (TNO
SDO)
1999 CG119 (TNO
SDO)
Objects recently assigned numbers:
1999 OX3 = (44594)
2000 PV29 = (45802)
Objects recently assigned names:
1999 HX11 = Rhadamanthus
Current number of TNOs: 563 (and Pluto & Charon, and 7 other TNO binary companions)
Current number of Centaurs/SDOs: 120
Almost all of the >500 known Kuiper belt objects (KBOs) have been
discovered within 50 AU of the Sun. One possible explanation for the
observed lack of KBOs beyond 50 AU is that the distant Kuiper belt is
dynamically very cold, and thus thin enough on the sky to have slipped
between previous deep survey fields. We have completed a survey
designed to search for a dynamically cold distant Kuiper belt near the
invariable plane of the Solar system. In
we have
discovered a total of 33 KBOs and 1 Centaur, but no objects in
circular orbits beyond 50 AU. We find that we can exclude at 95% CL
the existence of a distant disk inclined by
to the
invariable plane and containing more than 1.2 times as many D>185 km KBOs
between 50 and 60 AU as the observed inner Kuiper belt, if the distant
disk is thinner than
.
To appear in: The Astronomical Journal
For preprints, contact rhiannon@astro.lsa.umich.edu
A mean motion resonance with Neptune is one of the major dynamical characteristics of the Edgeworth-Kuiper Belt Objects that spread over the outside of Neptune's orbit. We investigated the influence of Jupiter, Saturn, and Uranus on the dynamical structure of the 2:3 mean motion resonance with Neptune. Since the distance between the planets and objects has great influence on the dynamical structure, numerical integrations were carried out for test particles for 5 Myr under five fictitious solar-system models having different configurations. In discussion about the results, we concentrate on the size of the EKBO eccentricities, e, because they have an especially close relation to the orbital evolution; for example, larger e objects have more opportunities to encounter other objects or planets. By comparing the results of each model, it was found that the resonance structure is not largely affected by Jupiter and Saturn, and that the largest eof the resonant objects depends on the distance between Uranus and the resonance. The distance also influences the structure around the resonance because of variation in the secular resonance positions. We further found that the largest e values of the non-resonant objects at each semi-major axis do not depend on the distance from Uranus; however, they depend on the distance from Neptune.
Published in: Publications of the Astronomical Society of Japan, 54, 493 (2002 June)
For reprints, contact tetsu@subaru.naoj.org
We illuminate dynamical properties of Kuiper Belt Objects (KBOs) in
the 3:2 (``Plutino'') and 2:1 (``Twotino'') Neptunian resonances
within the model of resonant capture and migration. We analyze a
series of numerical integrations, each involving the 4 migratory giant
planets and 400 test particles distributed throughout trans-Neptunian
space, to measure the efficiencies of capture into the 3:2 and 2:1
resonances, the efficiencies of capture into Kozai-type secular
resonances, and the libration centers and amplitudes of resonant
particles, all as functions of the migration speed. We synthesize
instantaneous snapshots of the spatial distribution of 
104resonant KBOs, from which we derive the longitudinal variation of the
sky density of each resonant family. Twotinos cluster
away from Neptune's longitude, while Plutinos cluster
away. Such longitudinal clustering persists even for surveys that are
not volume-limited in their ability to detect resonant KBOs.
Remarkably, between 
and 
of Neptune's
longitude, we find the ratio of sky densities of Twotinos to Plutinos
to be nearly unity despite the greater average distance of Twotinos,
assuming the two resonant populations are equal in number and share
the same size, albedo, and inclination distributions. We couple our
findings to observations to crudely estimate that Plutinos
intrinsically outnumber Twotinos by a factor not exceeding 3.
Most strikingly, the migration model predicts an asymmetry in the
spatial distribution of Twotinos: more Twotinos are expected to lie at
longitudes behind that of Neptune than ahead of it. The magnitude of
the asymmetry amplifies dramatically with faster rates of migration
and can be as large as 300%. A differential measurement of the
sky density of 2:1 resonant objects behind of and in front of
Neptune's longitude would powerfully constrain the migration history
of that planet.
To appear in: The Astronomical Journal
For preprints, contact echiang@astron.berkeley.edu
or on the web at
http://astron.berkeley.edu/~echiang/ppp/ppp.html
The dust produced in the Kuiper Belt (KB) spreads throughout the Solar System forming a dust disk. We numerically model the orbital evolution of KB dust and estimate its equilibrium spatial distribution and its brightness and spectral energy distributions (SED), assuming greybody absorption and emission by the dust grains. We show that the planets modify the KB disk SED, so potentially we can infer the presence of planets in spatially unresolved debris disks by studying the shape of their SEDs. We point out that there are inherent uncertainties in the prediction of structure in the dust disk, owing to the chaotic dynamics of dust orbital evolution imposed by resonant gravitational perturbations of the planets.
To appear in: The Astronomical Journal
For preprints, contact amaya@as.arizona.edu
or on the web at
http://www.lpl.arizona.edu/people/faculty/malhotra2.html
The Kuiper Belt zone is unique insofar as the major heat sources of
objects a few tens of kilometers in size -- solar radiation on the
one hand, and radioactive decay on the other -- have comparable
power. This leads to unique evolutionary patterns, with heat waves
propagating inward from the irradiated surface and outwards from the
radioactively heated interior. A major radioactive source that is
considered in this study is 26Al. The long-term evolution of
several models with characteristics typical of Kuiper Belt objects is
followed by means of a 1-D numerical code that solves the heat and
mass balance equations on a spherically symmetric grid. The free
parameters considered are radius (10-500 km), heliocentric distance
(30-120 AU), and initial 26Al content (0-
by
mass). The initial composition assumed is a porous mixture of ices
(H2O, CO, and CO2) and dust. Gases released in the interior are
allowed to escape to the surface. It is shown that, depending on
parameters, the interior may reach quite high temperatures (up to
180 K). The models suggest that Kuiper Belt objects are likely to
lose the ices of very volatile species during early evolution; ices of
less volatile species are retained in a surface layer, about 1 km
thick. The models indicate that the amorphous ice crystallizes in the
interior, and hence some objects may also lose part of the volatiles
trapped in amorphous ice. Generally, the outer layers are far less
affected than the inner part, resulting in a stratified composition
and altered porosity distribution. These changes in structure and
composition should have significant consequences for the short-period
comets, which are believed to be descendants of Kuiper Belt objects.
To appear in: Icarus
For preprints, contact dina@planet.tau.ac.il
The outer Solar system body 1999 UG5 is a Centaur of medium
brightness and slightly redder color when compared to other
Centaurs. Similar to at least one fifth of the known Centaurs, it is a
Saturn-crosser with a mean orbital distance between Saturn
and Uranus. We present optical photometry data and NIR spectra
obtained during September, November, and December, 2000. We find a
rotation period of
hours with an amplitude of
mag, and a phase curve with a Lumme-Bowell G value of
.
BVRI colors are reported, and confirm the red
spectral gradient observed previously. Our spectra reveal that this redward
slope extends into NIR wavelengths and indicate possible localized
differences in the surface composition.
To appear in: Publications of the Astronomical Society of the Pacific
For preprints, contact bauer@ifa.hawaii.edu
Kuiper Belt Objects (KBOs) are generally very faint and cannot in
practice be monitored with a well-sampled long-term light curve; so
our discovery of the bright KBO 2000 EB173 offers an excellent
opportunity for synoptic studies. We present a well-sampled
photometric time series (77 R magnitudes and 29 V magnitudes on 78
nights) over a 225-day time span centered on the 2001 opposition. The
light curve (corrected to the year 2001 opposition distance) varies
from 19.11 to 19.39 mag with a single peak that is smooth, time
symmetric, and coincident with opposition. All variations in the
light curve are consistent with a linear opposition surge (
,
where 
is the solar phase angle),
while any rotational modulation must have a peak-to-peak amplitude of
less than 0.097 mag. This is the first measured opposition surge for
any KBO (other than Pluto). The V-R color is
,
with
no apparent variation with phase at the few percent level. With
R=19.11 at opposition, 2000 EB173 remains the brightest known
KBO and a prime target for future photometric and spectroscopic
studies.
To appear in: Icarus
For preprints, contact schaefer@astro.as.utexas.edu
or on the web at http://arXiv.org/abs/astro-ph/0208261
We present a statistical study of the detectability of lightcurves of Kuiper Belt objects (KBOs). Some Kuiper Belt objects display lightcurves that appear ``flat'', i.e., there are no significant brightness variations within the photometric uncertainties. Under the assumption that KBO lightcurves are mainly due to shape, the lack of brightness variations may be due to (1) the objects have very nearly spherical shapes, or (2) their rotation axes coincide with the line of sight. We investigate the relative importance of these two effects and relate it to the observed fraction of ``flat'' lightcurves. This study suggests that the fraction of KBOs with detectable brightness variations may provide clues about the shape distribution of these objects. Although the current database of rotational properties of KBOs is still insufficient to draw any statistically meaningful conclusions, we expect that, with a larger dataset, this method will provide a useful test for candidate KBO shape distributions.
To appear in: Icarus
For preprints, contact placerda@strw.leidenuniv.nl
Formation of Kuiper Belt Binaries
Peter Goldreich1, Yoram Lithwick1, and Re'em Sari1
1 Theoretical Astrophysics, Caltech 130-33, Pasadena, CA 91125 USA
Submitted to: Nature
For preprints, contact yoram@tapir.caltech.edu
or on the web at http://arXiv.org/abs/astro-ph/0208490
Out on The Edge
W.B. McKinnon1
1 Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, Saint Louis, MO 63130, USA
Published in: Nature, 418, 135 (2002)
For preprints, contact mckinnon@levee.wustl.edu
Focus on Education: Striking Kuiper Belt Gold
Jodi Asbell-Clarke1
1 TERC, 2067 Massachusetts Avenue, Cambridge, MA 02140, USA
Published in: Mercury, 31, 13 (2002)
For preprints, contact Jodi_Asbell-Clarke@terc.edu
Dusty Rings: Signposts of Recent Planet Formation
Scott J. Kenyon1 and Benjamin C. Bromley2
1 Smithsonian Astrophysical Observatory, 60 Garden Street,
Cambridge, MA 02138, USA
2 Department of Physics, University of Utah, 201 JFB, Salt Lake City,
UT 84112, USA
To appear in: The Astrophysical Journal Letters
For preprints, contact skenyon@cfa.harvard.edu
or on the web at http://arXiv.org/abs/astro-ph/0208155
On the Initial Thermal Evolution of Kuiper Belt Objects
W.B. McKinnon1
1 Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, Saint Louis, MO 63130, USA
To appear in: Proceedings of Asteroids, Comets, Meteors 2002
For preprints, contact mckinnon@levee.wustl.edu
The above submission reminded me that abstracts of ACM presentations
are available at:
http://berlinadmin.dlr.de/SGF/acm2002/Abstractweblist-020618-Session.html
The DPS meeting will be held in Birmingham, Alabama, USA on October 6-11
Details are available at: http://csem.engin.umich.edu/dps/
The meeting program shows the following Kuiper belt related sessions:
http://www.aas.org/publications/baas/v34n3/dps2002/S70.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S90.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S170.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S200.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S210.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S260.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S280.htm
http://www.aas.org/publications/baas/v34n3/dps2002/S290.htm
In the last 20 years celestial mechanics has achieved spectacular results on the structure and evolution of our solar system. With a solid theoretical basis this book describes recent results on solar system dynamics, with emphasis on planets and small bodies. It begins by presenting the fundamental concepts of Hamiltonian systems theory, necessary to work at ease in celestial mechanics. Celestial mechanics itself is then considered, including the secular motion of planets and small bodies and mean motion resonant dynamics. Modern Celestial Mechanics will be of interest to graduate students and researchers of astronomy and astrophysics.
Contents
Published in:
Advances in Astronomy and Astrophysics, Volume 5
(ed. Taylor & Francis; London and New York)
Author contact morby@obs-nice.fr
Available for purchase on the web at http://www.tandf.co.uk/
We accept submissions for the following sections:
Distant EKOs is not a refereed publication, but is a tool for furthering communication among people interested in Kuiper belt research. Publication or listing of an article in the Newsletter or the web page does not constitute an endorsement of the article's results or imply validity of its contents. When referencing an article, please reference the original source; Distant EKOs is not a substitute for peer-reviewed journals.