Science Archives Publication System

Multiplicity of very low-mass objects in the Upper Scorpius OB association: a possible wide binary population

DOI: 10.1051/0004-6361:20054252 Bibcode: 2006A&A...451..177B

Béjar, V. J. S.; Schirmer, M.; Ghez, A. M. +5 more

Aims.Properties of multiplicity, such as the multiplicity frequency, the distribution of mass ratios and periods, provide important informations on the formation processes at work. Studying these properties in different environments and at different ages allows us to constrain the models of formation and to understand the influence of the environm…

2006 • Astronomy and Astrophysics

eHST 50

A Method for Deriving Accurate Gas-Phase Abundances for the Multiphase Interstellar Galactic Halo

DOI: 10.1086/497352 Bibcode: 2006ApJ...637..333H

Sembach, Kenneth R.; Savage, Blair D.; Howk, J. Christopher

We describe a new method for accurately determining total gas-phase abundances for the Galactic halo interstellar medium with minimal ionization uncertainties. For sight lines toward globular clusters containing both ultraviolet-bright stars and radio pulsars, it is possible to measure column densities of H I and several ionization states of selec…

2006 • The Astrophysical Journal

eHST 50

²⁶Al in the inner Galaxy. Large-scale spectral characteristics derived with SPI/INTEGRAL

DOI: 10.1051/0004-6361:20054301 Bibcode: 2006A&A...449.1025D

Wang, W.; Strong, A. W.; Knödlseder, J. +12 more

Aims.We performed a spectroscopic study of the 1809 keV gamma-ray line from ²⁶Al decay in the Galaxy using the SPI imaging spectrometer with its high-resolution Ge detector camera on the INTEGRAL observatory. Methods.We analyzed observations of the first two mission years, fitting spectra from all 7130 telescope pointings in narrow ener…

2006 • Astronomy and Astrophysics

INTEGRAL 50

Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

DOI: 10.1051/0004-6361:20053054 Bibcode: 2006A&A...446..707B

Sotin, C.; Brown, R. H.; Baines, K. H. +23 more

The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO{2}, and ferrous iron. Iapetus contains CO{2} and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be C…

2006 • Astronomy and Astrophysics

Cassini 50

Infrared Observations of the Helix Planetary Nebula

DOI: 10.1086/507944 Bibcode: 2006ApJ...652..426H

Smith, Howard A.; Marengo, Massimo; Hora, Joseph L. +1 more

We have mapped the Helix (NGC 7293) planetary nebula (PN) with the IRAC instrument on the Spitzer Space Telescope. The Helix is one of the closest bright PNs and therefore provides an opportunity to resolve the small-scale structure in the nebula. The emission from this PN in the 5.8 and 8 µm IRAC bands is dominated by the pure rotational li…

2006 • The Astrophysical Journal

eHST 50

Numerical interpretation of high-altitude photoelectron observations

DOI: 10.1016/j.icarus.2005.10.036 Bibcode: 2006Icar..182..383L

Coates, A. J.; Kallio, E.; Fedorov, A. +47 more

The Electron Spectrometer (ELS) instrument of the ASPERA-3 package on the Mars Express satellite has recorded photoelectron energy spectra up to apoapsis ( ∼10,000 km altitude). The characteristic photoelectron shape of the spectrum is sometimes seen well above the ionosphere in the evening sector across a wide range of near-equatorial latitudes. …

2006 • Icarus

MEx 50

New developments in SOLAR2000 for space research and operations

DOI: 10.1016/j.asr.2005.08.015 Bibcode: 2006AdSpR..37..347T

Tobiska, W. Kent; Bouwer, S. Dave

The SOLAR2000 (S2K) project provides solar spectral irradiances and integrated solar irradiance proxies for space researchers as well as ground- and space-based operational users. The S2K model currently represents empirical solar irradiances and integrated irradiance proxies covering the spectral range from the X-rays through the far infrared and…

2006 • Advances in Space Research

SOHO 50

Star Formation History of the Hubble Ultra Deep Field: Comparison with the Hubble Deep Field-North

DOI: 10.1086/505568 Bibcode: 2006ApJ...647..787T

Dickinson, Mark; Fan, Xiaohui; Thompson, Rodger I. +3 more

We use the NICMOS Treasury and ACS HUDF images to measure the extinction-corrected star formation history for 4681 galaxies in the region common to both images using the star formation rate distribution function and other techniques similar to those employed with the NICMOS and WFPC2 images in the HDFN. Unlike the HDFN, the NICMOS region of the HU…

2006 • The Astrophysical Journal

eHST 50

Venus Express: Scientific goals, instrumentation, and scenario of the mission

DOI: 10.1134/S0010952506040071 Bibcode: 2006CosRe..44..334T

Barabash, S.; Zhang, T. L.; Bertaux, J. -L. +23 more

The first European mission to Venus (Venus Express) is described. It is based on a repeated use of the Mars Express design with minor modifications dictated in the main by more severe thermal environment at Venus. The main scientific task of the mission is global exploration of the Venusian atmosphere, circumplanetary plasma, and the planet surfac…

2006 • Cosmic Research

VenusExpress 50

Predictions of the electrical conductivity and charging of the aerosols in Titan's atmosphere

DOI: 10.1016/j.icarus.2005.10.030 Bibcode: 2006Icar..181..527B

Tripathi, S.; Whitten, R. C.; Borucki, W. J. +2 more

The electrical conductivity and electrical charge on the aerosols in atmosphere of Titan are computed for altitudes between 0 and 400 km. Ionization of methane and nitrogen due to galactic cosmic rays (GCR) is important at night where these ions are converted to ion clusters such as CH ⁺₅CH ₄, C ₇H ^…

2006 • Icarus

Cassini 50