[X] My Assistant

[Guest_BruceMoomaw_*]

And this time, thank God, you can link to them individually:

http://www.on.br/acm2005/abstract.html

[ljk4-1]

Paper: astro-ph/0510200
Date: Thu, 6 Oct 2005 22:27:54 GMT (481kb)

Title: The origin of planetary impactors in the inner solar system

Authors: Robert G. Strom, Renu Malhotra, Takashi Ito, Fumi Yoshida, David A.
Kring

Comments: 12 pages (including 4 figures)

Journal-ref: Science 309, 1847-1850 (2005)
\\
New insights into the history of the inner solar system are derived from the
impact cratering record of the Moon, Mars, Venus and Mercury, and from the size
distributions of asteroid populations. Old craters from a unique period of
heavy bombardment that ended $\sim$3.8 billion years ago were made by asteroids
that were dynamically ejected from the main asteroid belt, possibly due to the
orbital migration of the giant planets. The impactors of the past $\sim$3.8
billion years have a size distribution quite different from the main belt
asteroids, but very similar to the population of near-Earth asteroids.

\\ ( http://arXiv.org/abs/astro-ph/0510200 , 481kb)

[ljk4-1]

Paper: astro-ph/0510454

Date: Fri, 14 Oct 2005 20:39:13 GMT (124kb)

Title: Lightcurves of 20--100 kilometer Kuiper Belt Objects using the Hubble
Space Telescope

Authors: David E. Trilling, Gary M. Bernstein

Comments: AJ, in press. Tables 1-4 will be electronic only in published version
but appear here in full. Figures 1,3,5 in color


We report high precision photometry of three small and one larger Kuiper Belt
Objects (KBOs) obtained with the Advanced Camera for Surveys onboard the Hubble
Space Telescope (ACS/HST). The three small bodies are the smallest KBOs for
which lightcurve measurements are available. 2003 BF91 has a diameter of 20
kilometers (assuming 10% albedo) and a 1.09 magnitude, 9.1-hour lightcurve that
is feasibly explained by the rotation of an elongated, coherent body that is
supported by material strength and best imagined as an icy outer Solar System
analog to asteroid (243) Ida. Two other small KBOs, 2003 BG91 and 2003 BH91
(diameters 31 and 18 km, with albedo 10%), exhibit an unremarkable lightcurve
and no detectable photometric variation, respectively. For the larger KBO 2000
FV53 (116 km diameter, assuming 10% albedo) we strongly detect a non-sinusoidal
periodic (7.5 hours) brightness variation with a very small amplitude (0.07
mag).

This KBO may be nearly spherical, a result that might not be unusual in
the Kuiper Belt but would be remarkable among outer Solar System satellites of
similar size. We carry out a study of possible physical states and bulk
densities under the assumptions of both fluid equilibrium and finite, non-zero
internal friction. The densities for the these KBOs are likely to be in the
range 1--2 g/cm3, and a plausible solution for 2000 FV53 is a rubble pile of
this density that is held slightly out of the minimum-energy shape by internal
friction among constituent blocks that are relatively small. Our interpretation
of 2000 FV53 as a pulverized but essentially primordial object and 2003 BF91 as
a collisional fragment is consistent with models of collisional timescales in
the outer Solar System. We compile all published KBO lightcurve data and
compare our results to the larger population. [abridged]

\\ ( http://arXiv.org/abs/astro-ph/0510454 , 124kb)

[ljk4-1]

Paper: astro-ph/0511219

Date: Tue, 8 Nov 2005 13:12:08 GMT (261kb)

Title: Dust in Resonant Extrasolar Kuiper Belts - Grain Size and Wavelength
Dependence of Disk Structure

Authors: M. C. Wyatt

Comments: 12 pages, accepted by ApJ
\\
This paper considers the distribution of dust which originates in the
break-up of planetesimals that are trapped in resonance with a planet. There
are three grain populations with different spatial distributions: (I) large
grains have the clumpy resonant distribution of the planetesimals; (II)
moderate sized grains are no longer in resonance and have an axisymmetric
distribution; (III) small grains are blown out of the system by radiation
pressure and have a distribution which falls off oc 1/r, however these grains
can be further divided into subclasses: (IIIa) grains produced from pop I that
exhibit trailing spiral structure emanating from the clumps; and (IIIb) grains
produced from pop II that have an axisymmetric distribution. Since observations
in different wavebands are sensitive to different sized dust grains,
multi-wavelength imaging can be used to test models for the origin of debris
disk structure. For example, a disk with no blow-out grains would appear clumpy
in the sub-mm, but smooth at mid- to far-IR wavelengths. The wavelength of the
transition is indicative of the mass of the perturbing planet. The size
distribution of Vega's disk is modeled in the light of the recent Spitzer
observations. The origin of the large quantities of pop III grains seen by
Spitzer must be in the destruction of the grains seen in the sub-mm, and so at
high resolution and sensitivity the mid- to far-IR structure of Vega's disk is
predicted to include spiral structure emanating from the sub-mm clumps.

\\ ( http://arXiv.org/abs/astro-ph/0511219 , 261kb)

[ljk4-1]

Paper: astro-ph/0511223

Date: Tue, 8 Nov 2005 15:23:50 GMT (297kb)

Title: Performance study of ground-based infrared Bracewell interferometers -
Application to the detection of exozodiacal dust disks with GENIE

Authors: O. Absil, R. den Hartog, P. Gondoin, P. Fabry, R. Wilhelm, P. Gitton,
and F. Puech

Comments: A&A, accepted
\\
Nulling interferometry, a powerful technique for high-resolution imaging of
the close neighbourhood of bright astrophysical objets, is currently considered
for future space missions such as Darwin or the Terrestrial Planet Finder
Interferometer (TPF-I), both aiming at Earth-like planet detection and
characterization. Ground-based nulling interferometers are being studied for
both technology demonstration and scientific preparation of the Darwin/TPF-I
missions through a systematic survey of circumstellar dust disks around nearby
stars. In this paper, we investigate the influence of atmospheric turbulence on
the performance of ground-based nulling instruments, and deduce the major
design guidelines for such instruments. End-to-end numerical simulations allow
us to estimate the performance of the main subsystems and thereby the actual
sensitivity of the nuller to faint exozodiacal disks. Particular attention is
also given to the important question of stellar leakage calibration. This study
is illustrated in the context of GENIE, the Ground-based European Nulling
Interferometer Experiment, to be installed at the VLTI and working in the L'
band. We estimate that this instrument will detect exozodiacal clouds as faint
as about 50 times the Solar zodiacal cloud, thereby placing strong constraints
on the acceptable targets for Darwin/TPF-I.

\\ ( http://arXiv.org/abs/astro-ph/0511223 , 297kb)

[ljk4-1]

MIT Prof Lectures on Meteor, Asteroid Connection

“What makes me want to be a planetary scientist is that you have a
chance in your lifetime to fly missions that get real data,” said
Prof. Richard P. Binzel, planetary science, Massachusetts Institute
of Technology. Binzel gave a lecture to a...

http://www.cornellsun.com/vnews/display.v/...1/437449e7625bb

[ljk4-1]

Paper: astro-ph/0511370

Date: Fri, 11 Nov 2005 23:04:06 GMT (396kb)

Title: The Origin and Evolution of the Asteroid Main Belt

Authors: Philip R. Bidstrup, Henning Haack (Copenhagen Geological Museum), Anja
C. Andersen (Dark Cosmology Center), Rene Michelsen, John Leif Jorgensen
(Danish Technical University)

Comments: Conference proceedings for the 6th IAA International Conference on
"Low-Cost Planetary Missions" held October 11-13, 2005 in Kyoto, Japan

Report-no: NORDITA-2005-74
\\
Using a fully autonomous spacecraft - Bering - we propose to detect and study
sub-km asteroids from an orbit within the asteroid Main Belt. The main purpose
of the proposed Bering mission is to detect a statistically significant sample
of an expected population of approximately 10^(10) main belt asteroids in the
size range 1 m to 1 km. These asteroids are too faint to be observed using
Earth-based telescopes. Sub-km asteroids can be detected from spacecraft at
close range but due to the high relative velocities and the long communication
times this requires a fully autonomous spacecraft. Using theoretical estimates
of the distribution and abundance of sub-km asteroids we find that the Bering
mission would detect approximately 6 new sub-km asteroids per day. With an
expected lifetime for the mission of a few years we expect to detect and study
several thousand sub-km asteroids. Results from the Bering mission would allow
us to: 1) Provide further links between groups of meteorites and their parent
asteroids. 2) Constrain the cratering rate at planetary surfaces and thus allow
significantly improved cratering ages for terrains on Mars and other planets.
3) Constrain processes that transfer small asteroids from orbits in the main
belt to the inner Solar System.

\\ ( http://arXiv.org/abs/astro-ph/0511370 , 396kb)

[ljk4-1]

Paper: astro-ph/0511791

Date: Tue, 29 Nov 2005 14:25:19 GMT (148kb)

Title: The Capture of Centaurs as Trojans

Authors: J. Horner (Bern) and N. Wyn Evans (Cambridge)

Comments: 5 pages, 2 figures, submitted to MNRAS (Letters)
\\
Large scale simulations of Centaurs have yielded vast amounts of data, the
analysis of which allows interesting but uncommon scenarios to be studied. One
such rare phenomenon is the temporary capture of Centaurs as Trojans of the
giant planets. Such captures are generally short (10 kyr to 100 kyr), but occur
with sufficient frequency (about 40 objects larger than 1 km in diameter every
Myr) that they may well contribute to the present-day populations. Uranus and
Neptune seem to have great difficulty capturing Centaurs into the 1:1
resonance, while Jupiter captures some, and Saturn the most (80 %). We
conjecture that such temporary capture from the Centaur population may be the
dominant delivery route into the Saturnian Trojans. Photometric studies of the
Jovian Trojans may reveal outliers with Centaur-like as opposed to asteroidal
characteristics, and these would be prime candidates for captured Centaurs.

\\ ( http://arXiv.org/abs/astro-ph/0511791 , 148kb)