Infrared variability of Jupiter and Saturn

Infrared spectroscopy provides unique insights into the chemistry and dynamics of the atmospheres of Jupiter and Saturn, and of the enigmatic satellite of Saturn, Titan. The 5 micron spectral region of these objects is transparent to deep levels, and is therefore particularly useful for the identification of molecules that are present at very low (parts per billion) concentrations. In Titan, 5 micron observations probe atmospheric layers at or near the surface. Ground-based spectroscopy complements Voyager, Galileo, and Cassini measurements. The spectroscopy is sensitive to lower mixing ratios for selected molecules, while the on-board mass and infrared spectrometers probe molecules and levels that are inaccessible form the ground. The observations also provide time-based data for preparation of the upcoming missions

Eigensystem realization algorithm modal identification experiences with mini-mast

This paper summarizes work performed under a collaborative research effort between the National Aeronautics and Space Administration (NASA) and the German Aerospace Research Establishment (DLR, Deutsche Forschungsanstalt fur Luft- und Raumfahrt). The objective is to develop and demonstrate system identification technology for future large space structures. Recent experiences using the Eigensystem Realization Algorithm (ERA), for modal identification of Mini-Mast, are reported. Mini-Mast is a 20 m long deployable space truss used for structural dynamics and active vibration-control research at the Langley Research Center. A comprehensive analysis of 306 frequency response functions (3 excitation forces and 102 displacement responses) was performed. Emphasis is placed on two topics of current research: (1) gaining an improved understanding of ERA performance characteristics (theory vs. practice); and (2) developing reliable techniques to improve identification results for complex experimental data. Because of nonlinearities and numerous local modes, modal identification of Mini-Mast proved to be surprisingly difficult. Methods were available, ERA, for obtaining detailed, high-confidence results

A Re-examination of D-H-M in the Meṣad Ḥashavyahu Ostracon (KAI 200)

Although the contents of the seventh-century bce letter found on ostraca fragments at Meṣad ḤAshavyahu are relatively well understood, the proposed interpretation of one word has been too quickly accepted and should be challenged. This is the interpretation of graphic, in line 14, as a form of graphic, which is said to mean ‘be silent’. The association with graphic is not a foregone conclusion, however, and a survey of the biblical corpus demonstrates that a connection between II-graphic and II- graphic roots is exceptional rather than the norm. Furthermore, the existence of the root graphic is itself uncertain, and the claim that it means ‘be silent’ is questionable rather than established. Finally, the only biblical use of the root graphic, in Jer. 14:9, seems to have similar connotations and should be used to help interpret graphic in the letter

The Orbit, Mass, and Albedo of Transneptunian Binary 1999 RZ253

We have observed 1999 RZ253 with the Hubble Space Telescope at seven separate epochs and have fit an orbit to the observed relative positions of this binary. Two orbital solutions have been identified that differ primarily in the inclination of the orbit plane. The best fit corresponds to an orbital period, P=46.263 +0.006/-0.074 days, semimajor axis a=4,660 +/-170 km and orbital eccentricity e=0.460 +/-0.013 corresponding to a system mass m=3.7 +/-0.4 x10^18 kg. For a density of rho = 1000 kg m^-3 the albedo at 477 nm is p = 0.12 +/-0.01, significantly higher than has been commonly assumed for objects in the Kuiper Belt. Multicolor, multiepoch photometry shows this pair to have colors typical for the Kuiper belt with a spectral gradient of 0.35 per 100 nm in the range between 475 and 775 nm. Photometric variations at the four epochs we observed were as large as 12 +/-3% but the sampling is insufficient to confirm the existence of a lightcurve

A deep i-selected multi-waveband galaxy catalogue in the COSMOS field

In this paper we present a deep and homogeneous i-band selected multi-waveband catalogue in the COSMOS field covering an area of about 0.7 square-degree. Our catalogue with a formal 50 percent completeness limit for point sources of i~26.7 comprises about 290.000 galaxies with information in 8 passbands. We combine publicly available u, B, V, r, i, z, and K data with proprietary imaging in H band. We discuss in detail the observations, the data reduction, and the photometric properties of the H-band data. We estimate photometric redshifts for all the galaxies in the catalogue. A comparison with 162 spectroscopic redshifts in the redshift range 0 < z < 3 shows that the achieved accuracy of the photometric redshifts is (Delta_z / (z_spec+1)) ~0.035 with only ~2 percent outliers. We derive absolute UV magnitudes and investigate the evolution of the luminosity function evaluated in the rest-frame UV at 1500 Angstrom. There is a good agreement between the LFs derived here and the LFs derived in the FORS Deep Field. We see a similar brightening of M_star and a decrease of phi_star with redshift. The catalogue including the photometric redshift information is made publicly available.Comment: 20 pages, 17 figures, accepted for publication in MNRAS; high resulution paper: http://www.mpe.mpg.de/~gabasch/COSMOS/cosmos.pd

Rotational properties of the binary and non-binary populations in the Trans-Neptunian belt

We present results for the short-term variability of Binary Trans-Neptunian Objects (BTNOs). We performed CCD photometric observations using the 3.58 m Telescopio Nazionale Galileo, the 1.5 m Sierra Nevada Observatory telescope, and the 1.23 m Centro Astronomico Hispano Aleman telescope at Calar Alto Observatory. We present results based on five years of observations and report the short-term variability of six BTNOs. Our sample contains three classical objects: 2003MW12, or Varda, 2004SB60, or Salacia, and 2002 VT130; one detached disk object: 2007UK126; and two resonant objects: 2007TY430 and 2000EB173, or Huya. For each target, possible rotational periods and/or photometric amplitudes are reported. We also derived some physical properties from their lightcurves, such as density, primary and secondary sizes, and albedo. We compiled and analyzed a vast lightcurve database for Trans-Neptunian Objects (TNOs) including centaurs to determine the lightcurve amplitude and spin frequency distributions for the binary and non-binary populations. The mean rotational periods, from the Maxwellian fits to the frequency distributions, are 8.63+/-0.52 h for the entire sample, 8.37+/-0.58 h for the sample without the binary population, and 10.11+/-1.19 h for the binary population alone. Because the centaurs are collisionally more evolved, their rotational periods might not be so primordial. We computed a mean rotational period, from the Maxwellian fit, of 8.86+/-0.58 h for the sample without the centaur population, and of 8.64+/-0.67 h considering a sample without the binary and the centaur populations. According to this analysis, regular TNOs spin faster than binaries, which is compatible with the tidal interaction of the binaries. Finally, we examined possible formation models for several systems studied in this work and by our team in previous papers.Comment: Accepted for publication in Astronomy and Astrophysics (June 26th, 2014); minor changes with published version; 21 pages, 17 figures, 7 table

Discovery of a Binary Centaur

We have identified a binary companion to (42355) 2002 CR46 in our ongoing deep survey using the Hubble Space Telescope's High Resolution Camera. It is the first companion to be found around an object in a non-resonant orbit that crosses the orbits of giant planets. Objects in orbits of this kind, the Centaurs, have experienced repeated strong scattering with one or more giant planets and therefore the survival of binaries in this transient population has been in question. Monte Carlo simulations suggest, however, that binaries in (42355) 2002 CR46 -like heliocentric orbits have a high probability of survival for reasonable estimates of the binary's still-unknown system mass and separation. Because Centaurs are thought to be precursors to short period comets, the question of the existence of binary comets naturally arises; none has yet been definitively identified. The discovery of one binary in a sample of eight observed by HST suggests that binaries in this population may not be uncommon.Comment: 20 pages, 4 figures, 1 table accepted for publication in Icaru