MPEC H21 announced the discovery of a Neptunian trojan (1:1 resonannce) by
Sheppard, Trujillo, and Jewitt. The object 2004 UP10 is the
second known Neptunian trojan (2001 QR322 being the first).
MPEC: http://cfa-www.harvard.edu/mpec/K05/K05H21.html
There were 20 new TNO discoveries announced since the previous issue of Distant EKOs:
2005 ER318, 2005 GA187, 2005 GB187, 2005 GC187, 2005 GD187, 2005 GE187, 2005 GF187, 2005 GW186, 2005 GX186, 2005 GY186, 2005 GZ186, 2004 SB60, 2004 SC60, 2005 EW318, 2005 EX318, 2005 GX206, 2005 GY206, 2005 GZ206, 2005 JA175, 2005 JZ174
and 1 new Neptunian Trojan discovery:
2004 UP10
Reclassified objects:
2004 DJ71 (TNOSDO)
2003 GF55 (SDO
2005 EB299 (Centaur
2001 KE77 (SDO
2003 LG7 (TNO
Current number of TNOs: 886 (and Pluto & Charon, and 12 other TNO binary companions)
Current number of Centaurs/SDOs: 151
Current number of Neptune Trojans: 2
Out of a total of 1039 objects:
500 have measurements from only one opposition
410 of those have had no measurements for more than a year
203 of those have arcs shorter than 10 days
(for more details, see:
http://www.boulder.swri.edu/ekonews/objects/recov_stats.gif)
The ``Cold Classical'' Kuiper Belt is the only part of the Kuiper
Belt where objects show distinct color statistics from the rest of the
transneptunian population. Cold Classical orbits are also likely to have
been among the least dynamically perturbed since the time of accretion.
As such, Cold Classical objects are especially interesting targets for
compositional investigation by means of near-infrared spectroscopy.
In this paper we report the first published infrared spectrum of a
likely member of this unique class of objects. A 1.4 to 2.5 
m
spectrum of the Cold Classical candidate object (79360) 1997 CS29
obtained at Keck 1 is spectrally featureless.
To appear in: The Astronomical Journal
For preprints, contact W.Grundy@lowell.edu
We present low resolution K band spectra taken at the Gemini 8 meter
telescope of (90377) Sedna and (90482) Orcus (provisional designations
2003 VB12 and 2004 DW, respectively), currently the two minor
planets with the greatest absolute magnitudes (i.e. the two most
reflective minor planets). We place crude limits on the surface
composition of these two bodies using a Hapke model for a wide variety
of assumed albedos. The unusual minor planet (90377) Sedna was
discovered on November 14, 2003 UT at roughly 90 AU with 1.6 times the
heliocentric distance and perihelion distance of any other bound minor
planet. It is the first solar system object discovered between the
Kuiper Belt and the Oort Cloud, and may represent a transition
population between the two. The reflectance spectrum of (90377) Sedna
appears largely featureless at the current signal-to-noise ratio,
suggesting a surface likely to be highly processed by cosmic rays.
For large grain models (100 micron to 1 cm) we find that
(90377) Sedna cannot have more than 70% surface fraction of water ice or
more than 60% surface fraction of methane ice to 
confidence.
Minor planet (90482) Orcus shows strong water ice absorption
corresponding to less than 50% surface fraction for grain models
25 micron and larger. Orcus cannot have more than 30% of its surface
covered by large (100 mm to 1 cm) methane grains to
confidence.
To appear in: Astrophysical Journal, 627 (2005 July 10)
For preprints, contact trujillo@gemini.edu
or on the web at http://xxx.lanl.gov/abs/astro-ph/0504280
In April 2004, we obtained visible and near-infrared spectroscopy and photometry of the Transneptunian Object (TNO) 90482 Orcus (2004 DW) with the European Southern Observatory (ESO) 8-m telescopes of the Very Large Telescope (VLT) in Chile. This object, discovered on February 17, 2004, is one of the largest known TNOs, and it belongs to the dynamical class of Plutinos. The high signal-to-noise ratio visible spectrum recorded on April 11, 2004, is nearly flat, in good agreement with the BVRI photometry we obtained the same night and with photometric measurements from Rabinowitz et al. (2004). The near-infrared spectra (J, H, and K bands) were obtained on April 11, 12, and 21, 2004. Relatively strong absorptions attributed to water ice were detected around 1.5 and 2 microns. We compare these data with spectra of Orcus obtained at the 3.56-m Telescopio Nazionale Galileo (TNG) by Fornasier et al. (2004a). Only two of the TNOs observed so far exhibit stronger water ice absorptions in their spectra than Orcus. Attempts to model the entire visible-near infrared spectrum yield tentative fits with mixtures of water ice and carbonaceous compounds.
To appear in: Astronomy & Astrophysics
For preprints, contact Catherine.deBergh@obspm.fr
Trans-Neptunian Objects (TNOs) and Centaurs display the widest color diversity in comparison to other small Solar system bodies. The investigation of their properties can help in understanding the evolution of these objects. In this paper we propose a classification scheme based on multivariable statistical analysis of a homogeneous, high quality set of B-V, V-R, V-I and V-J colors indices. Analyzing a sample of 51 objects and using a high confidence level, four groups have been identified and named : BB, BR, IR and RR. The group BB contains objects with neutral color, RR those with very red color, while the others have intermediate behavior. We extended the analysis of other 84 objects for which three colors are available obtaining a preliminary classification. A tentative interpretation of these groups in terms of surface characteristics is given.
To appear in: The Astronomical Journal (2005 September)
For preprints, contact antonella.barucci@obspm.fr
Planar Resonant Periodic Orbits in Kuiper Belt Dynamics
George Voyatzis1 and Thomas Kotoulas1
1 University of Thessaloniki, Department of Physics GR-541 24 Thessaloniki, Greece
Preprints on the web at
http://arxiv.org/abs/astro-ph/0502579
Origin of the Orbital Architecture of the Giant Planets of the Solar System
K. Tsiganis1, R. Gomes1,2, A. Morbidelli1, and H.F. Levison1,3
1 Observatoire de la C™te d' Azur, CNRS, BP 4229, 06304 Nice Cedex 4, France
2 GEA/OV/UFRJ and ON/MCT, Ladeira do Pedro Antonio, 43-Centro 20.080-090,
Rio de Janeiro, RJ, Brazil
3 Department of Space Studies, Southwest Research Institute, 1050 Walnut
Street, Suite 400, Boulder, Colorado 80302, USA
Published in: Nature, 435, 459 (2005 May 26)
For preprints, contact hal@boulder.swri.edu
or on the web at http://www.obs-nice.fr/morby/Ref_list.html
Chaotic Capture of Jupiter's Trojan Asteroids in the Early Solar System
A. Morbidelli1, and H. F. Levison1,3,K. Tsiganis1, and R. Gomes1,2
1 Observatoire de la C™te d' Azur, CNRS, BP 4229, 06304 Nice Cedex 4, France
2 GEA/OV/UFRJ and ON/MCT, Ladeira do Pedro Antonio, 43-Centro 20.080-090,
Rio de Janeiro, RJ, Brazil
3 Department of Space Studies, Southwest Research Institute, 1050 Walnut
Street, Suite 400, Boulder, Colorado 80302, USA
Nature, 435, 462 (2005 May 26)
For preprints, contact hal@boulder.swri.edu
or on the web at http://www.obs-nice.fr/morby/Ref_list.html
Origin of the Cataclysmic Late Heavy Bombardment Period of the Terrestrial Planets
R. Gomes1,2, H. F. Levison1,3, K. Tsiganis1, and A. Morbidelli1
1 Observatoire de la C™te d' Azur, CNRS, BP 4229, 06304 Nice Cedex 4, France
2 GEA/OV/UFRJ and ON/MCT, Ladeira do Pedro Antonio, 43-Centro 20.080-090,
Rio de Janeiro, RJ, Brazil
3 Department of Space Studies, Southwest Research Institute, 1050 Walnut
Street, Suite 400, Boulder, Colorado 80302, USA
Nature, 435, 466 (2005 May 26)
For preprints, contact hal@boulder.swri.edu
or on the web at http://www.obs-nice.fr/morby/Ref_list.html
Cometary D:H Ratios and the Formation of the Solar System
J. Horner1 and O. Mousis2
1 Physikalisches Institüt, University of Bern, Sidlerstrasse
5, CH-3012 Bern, Switzerland
2 Observatoire de Besançon, CNRS-UMR 6091, BP 1615, 25010
Besançon Cedex, France
Submitted to: Monthly Notices of the Royal Astronomical Society
For preprints, contact horner@phim.unibe.ch
The New Horizons 2 (NH2) Uranus-KB mission plans for a new science team, selected competitively by NASA. A workshop will be held from 7:00-9:00 pm on Wednesday, June 8th, which is the evening before the Boulder OPAG (Outer Planets Assessment Group) meeting. The goals of the NH2 workshop will be to ask for input to NH2 mission objectives, present the results of the NH2 study done this spring by NASA, and solicit desirable science team attributes for NH2.
The workshop will be held at the Southwest Research Institute's Department
of Space Studies, located at 1050 Walnut Street, Suite 400. This is just 4 blocks
from OPAG's Boulderado hotel site; see http://www.boulder.swri.edu/officeinfo.html
for maps. Food and drinks will be provided.
Interested participants should contact Carrie Chavez at cchavez@mail.arc.nasa.gov to register.
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.
