The Deep Ecliptic Survey ( DES)-a search optimized for the discovery of Kuiper belt objects ( KBOs) with the Blanco and Mayall 4 m telescopes at the Cerro Tololo Inter-American Observatory and Kitt Peak National Observatory-has covered 550 deg 2 from its inception in 1998 through the end of 2003. This survey has a mean 50% sensitivity at VR magnitude 22.5. We report here the discoveries of 320 designated KBOs and Centaurs for the period 2000 March through 2003 December and describe improvements to our discovery and recovery procedures. Our data and the data products needed to reproduce our analyses in this paper are available through the NOAO survey database. Here we present a dynamical classification scheme, based on the behavior of orbital integrations over 10 Myr. The dynamical classes, in order of testing, are ''Resonant,'' ''Centaur,'' ''Scattered-Near,'' ''Scattered-Extended,'' and ''Classical.'' ( These terms are capitalized when referring to our rigorous definitions.) Of the 382 total designated KBOs discovered by the DES, a subset of 196 objects have sufficiently accurate orbits for dynamical classification. Summary information is given for an additional 240 undesignated objects also discovered by the DES from its inception through the end of 2003. The number of classified DES objects (uncorrected for observational bias) are Classical, 96; Resonant, 54; Scattered-Near, 24; Scattered-Extended, 9; and Centaur, 13. We use subsets of the DES objects (which can have observational biases removed ) and larger samples to perform dynamical analyses on the Kuiper belt. The first of these is a determination of the Kuiper belt plane ( KBP), for which the Classical objects with inclinations less than 5 from the mean orbit pole yield a pole at R.A. = 273N92 AE 0N62 and decl. = 66N70 AE 0N20 (J2000), consistent with the invariable plane of the solar system. A general method for removing observational biases from the DES data set is presented and used to find a provisional magnitude distribution and the distribution of orbital inclinations relative to the KBP. A power-law model fit to the cumulative magnitude distribution of all KBOs discovered by the DES in the VR filter yields an index of 0:86 AE 0:10 (with the efficiency parameters for the DES fitted simultaneously with the population power law). With the DES sensitivity parameters fixed, we derive power-law indices of 0:74 AE 0:05, 0:52 AE 0:08, and 0:74 AE 0:15, respectively, for the Classical, Resonant, and Scattered classes. Plans for calibration of the DES detection efficiency function and DES magnitudes are discussed. The inclination distribution confirms the presence of ''hot'' and ''cold'' populations; when the geometric sin i factor is removed from the inclination distribution function, the cold population shows a concentrated ''core'' with a full width at half-maximum of approximately 4N6, while the hot population appears as a ''halo, '' extending beyond 30 . The inclination distribution is used to infer the KBO distribution in the sky, as a func...

As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1:1 (Trojan), 4:3, 3:2, 7:4, 2:1, and 5:2 Neptunian mean-motion resonances (MMRs). The previously unrecognized occupation of the 1:1 and 5:2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Among all resonant Kuiper belt objects (KBOs), the three observed members of the 5:2 MMR discovered by DES possess the largest semi-major axes (a ≈ 55.4 AU), the highest eccentricities (e ≈ 0.4), and substantial orbital inclinations (i ≈ 10 • ). Objects (38084) 1999HB 12 and possibly 2001KC 77 can librate with modest amplitudes of ∼90 • within the 5:2 MMR for at least 1 Gyr. Their trajectories cannot be explained by close encounters with Neptune alone, given the latter's current orbit. The dynamically hot orbits of such 5:2 resonant KBOs, unlike hot orbits of previously known resonant KBOs, may imply that these objects were pre-heated to large inclination and large eccentricity prior to

We have searched 101 Classical transneptunian objects for companions with the Hubble Space Telescope. Of these, at least 21 are binary. The heliocentric inclinations of the objects we observed range from 0.6-34• . We find a very strong anticorrelation of binaries with inclination. Of the 58 targets that have inclinations of less than 5.5• , 17 are binary, a binary fraction of 29± 7 6 %.All 17 are similar-brightness systems. On the contrary, only 4 of the 42 objects with inclinations greater than 5.5• have satellites and only 1 of these is a similar-brightness binary. This striking dichotomy appears to agree with other indications that the low eccentricity, non-resonant Classical transneptunian objects include two overlapping populations with significantly different physical properties and dynamical histories.

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We describe a strategy for scheduling astrometric observations to minimize the number re quired to determine the mutual orbits of binary transneptunian systems. The method is illustrat ed by application to Hubble Space Telescope observations of (42355) TyphonEchidna, reveal ing that Typhon and Echidna orbit one another with a period of 18.971 ± 0.006 days and a semi major axis of 1628 ± 29 km, implying a system mass of (9.49 ± 0.52) × 10 17 kg. The eccentric ity of the orbit is 0.526 ± 0.015. Combined with a radiometric size determined from Spitzer Space Telescope data and the assumption that Typhon and Echidna both have the same albedo, we estimate that their radii are 76 14 −16 and 42 8 −9 km, respectively. These numbers give an average bulk density of only 0.44 0.44 −0.17 g cm 3 , consistent with very low bulk densities recently reported for two other small transneptunian binaries.

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Neutron scattering results for the tetragonal compound CeRhIn5 give evidence for two crystal field (CF) excitations at 6.9 and 23.6 meV. The scattering can be fit assuming a set of CF parameters B 0 2 = -1.03 meV, B 0 4 = 0.044 meV and B 4 4 = 0.122 meV. To compare our results to previous work, we calculate the susceptibility and specific heat for this CF scheme, including a molecular field term λ =35 mol/emu to account for the Kondo effect. We also include a calculation based on these CF parameters that uses the non-crossing approximation to the Anderson model to estimate the effect of Kondo physics on the susceptibility, specific heat and neutron linewidths. PACS numbers: 75.30.Mb 75.20.Hr 71.27.+a 71.28.+d 61.10.Ht CeRhIn 5 crystallizes in the same tetragonal HoCoGa 5 structure as the heavy fermion superconductors CeIrIn 5 and CeCoIn 5 1,2,3 . At ambient pressure CeRhIn 5 undergoes a transition to an antiferromagnetic (AF) state at T N = 3.8 K 1,4 . With application of hydrostatic pressure the Néel temperature remains essentially constant until antiferromagnetism disappears and superconductivity appears at pressures above 15 kbar 1 . Recently, Pagliuso et al. 5 have suggested the importance of CF splitting to the ground state properties of the CeMIn 5 family of heavy fermion superconductors, underscoring the fact that the ultimate ground state achieved by a particular member of the family must grow out of the ground state crystal field doublet. Thus a careful determination of both the CF splitting and wavefunctions is important. To that end we have begun to directly probe the CF energy level splitting in the CeMIn 5 family using inelastic (IE) neutron scattering. The first step in our investigations has been determining the crystal field level scheme in CeRhIn 5 .In CeRhIn 5 , as in the other members of CeMIn 5 family, the crystal field Hamiltonian in tetragonal symmetry can be writtenwhere O m l and B m l are the Stevens operators and CF parameters respectively. The Ce 3+ J = 5/2 wavefunction splits into three doublets, Γ (1) 7 = {α[±5/2 + β[∓3/2 }, Γ (2) 7 = {β[±5/2 − α[∓3/2 } and Γ 6 = [±1/2 5 . An analysis of susceptibility and thermal expansion results 6 suggested crystal field levels Γ (2) 7 , Γ (1) 7and Γ 6 at E=0, 5.86 meV (68 K) and 28.43 meV (300 K) respectively, with β = 0.969 (yielding a nearly pure [±5/2 ground state). A subsequent study 5 based on an analysis of the susceptibility and specific heat suggested a similar scheme, but with splittings 6 and 12 meV (70 and 140 K). In this paper we report the results of an analysis of neutron scattering data for CeRhIn 5 which indicate that these initial estimates are nearly correct; our results have somewhat different values for the splittings and a smaller value for the mixing parameter β, i.e., a greater admixture of [∓3/2 into the [±5/2 ground state. To assist in comparison of our results to those of Pagliuso et al. 5 and Takeuchi et al. 6 , we report calculations of the specific heat and magnetic susceptibility based on our CF parameters which in...