312 research outputs found
Albedos and diameters of three Mars Trojan asteroids
We observed the Mars Trojan asteroids (5261) Eureka and (101429) 1998 VF31
and the candidate Mars Trojan 2001 FR127 at 11.2 and 18.1 microns using
Michelle on the Gemini North telescope. We derive diameters of 1.28, 0.78, and
<0.52 km, respectively, with corresponding geometric visible albedos of 0.39,
0.32, and >0.14. The albedos for Eureka and 1998 VF31 are consistent with the
taxonomic classes and compositions (S(I)/angritic and S(VII)/achrondritic,
respectively) and implied histories presented in a companion paper by Rivkin et
al. Eureka's surface likely has a relatively high thermal inertia, implying a
thin regolith that is consistent with predictions and the small size that we
derive.Comment: Icarus, in press. See companion paper 0709.1925 by Rivkin et al; two
minor typos fixe
Composition of the L5 Mars Trojans: Neighbors, not Siblings
Mars is the only terrestrial planet known to have Tro jan (co-orbiting)
asteroids, with a confirmed population of at least 4 objects. The origin of
these objects is not known; while several have orbits that are stable on
solar-system timescales, work by Rivkin et al. (2003) showed they have
compositions that suggest separate origins from one another. We have obtained
infrared (0.8-2.5 micron) spectroscopy of the two largest L5 Mars Tro jans, and
confirm and extend the results of Rivkin et al. (2003). We suggest that the
differentiated angrite meteorites are good spectral analogs for 5261 Eureka,
the largest Mars Trojan. Meteorite analogs for 101429 1998 VF31 are more varied
and include primitive achondrites and mesosiderites.Comment: 14 manuscript pages, 1 table, 6 figures. To be published in Icarus.
See companion paper 0709.1921 by Trilling et a
Senate\u27s Pie-In-The-Sky Treaty Interpretation: Power and the Quest for Legislative Supremacy
A Near-Infrared Search for Silicates in Jovian Trojan Asteroids
We obtained near-infrared (0.8 - 2.5 micron) spectra of seven Jovian Trojan
asteroids that have been formerly reported to show silicate-like absorption
features near 1 micron. Our sample includes the Trojan (1172) Aneas, which is
one of three Trojans known to possess a comet-like 10 micron emission feature,
indicative of fine-grained silicates. Our observations show that all seven
Trojans appear featureless in high signal-to-noise ratio spectra. The
simultaneous absence of the 1 micron band and presence of the 10 micron
emission can be understood if the silicates on (1172) Aneas are iron-poor.
In addition, we present near infrared observations of five optically grey
Trojans, including three objects from the collisionally produced Eurybates
family. The five grey Trojans appear featureless in the near infrared with no
diagnostic absorption features. The near infrared spectrum of Eurybates can be
best fitted with the spectrum of a CM2 carbonaceous chondrite, which hints that
the C-type Eurybates family members may have experienced aqueous alteration.Comment: 22 pages, 5 figures, accepted to be published in A
Federalism: Deference Meets Delegation: Which Is the Most Dangerous Branch
The following is a transcript of a 2016 Federalist Society panel entitled Federalism: Deference Meets Delegation: Which is the Most Dangerous Branch? The panel originally occurred on November 12, 2015, during the National Lawyers Convention in Washington, D.C. The panelists were: C. Boyden Gray, Attorney at Boyden, Gray and Associates and former U.S. Ambassador to the European Union; David B. Rivkin Jr., Partner at BakerHostetler; Neal K. Katyal, Attorney at Hogan Lovells and former acting U.S. Solicitor General; and John C. Eastman, Henry Salvatori Professor of Law & Community Service at Chapman University School of Law. The moderator was the Honorable Judge Brett Kavanaugh of the U.S. Court of Appeals, D.C. Circuit
Improved Structured Encryption for SQL Databases via Hybrid Indexing
We introduce a new technique for indexing joins in encrypted SQL databases called partially precomputed joins which achieves lower leakage and bandwidth than those used in prior constructions. These techniques are incorporated into state-of-the-art structured encryption schemes for SQL data, yielding a hybrid indexing scheme with both partially and fully precomputed join indexes. We then introduce the idea of leakage-aware query planning by giving a heuristic that helps the client decide, at query time, which index to use so as to minimize leakage and stay below a given bandwidth budget. We conclude by simulating our constructions on real datasets, showing that our heuristic is accurate and that partially-precomputed joins perform well in practice
ANSEL Photobot: A Robot Event Photographer with Semantic Intelligence
Our work examines the way in which large language models can be used for
robotic planning and sampling, specifically the context of automated
photographic documentation. Specifically, we illustrate how to produce a
photo-taking robot with an exceptional level of semantic awareness by
leveraging recent advances in general purpose language (LM) and vision-language
(VLM) models. Given a high-level description of an event we use an LM to
generate a natural-language list of photo descriptions that one would expect a
photographer to capture at the event. We then use a VLM to identify the best
matches to these descriptions in the robot's video stream. The photo portfolios
generated by our method are consistently rated as more appropriate to the event
by human evaluators than those generated by existing methods.Comment: ICRA 202
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