Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu’s parent body formed ~2 million years after the beginning of Solar System formation.

Astronomy & Astrophysics (A&A) is an international journal which publishes papers on all aspects of astronomy and astrophysics

Astronomy & Astrophysics (A&A) is an international journal which publishes papers on all aspects of astronomy and astrophysics

We present a power spectrum analysis of the Herschel-SPIRE observations of the Polaris flare, a high Galactic latitude cirrus cloud midway between the diffuse and molecular phases. The SPIRE images of the Polaris flare reveal for the first time the structure of the diffuse interstellar medium down to 0.01 parsec over a 10 square degrees region. These exceptional observations highlight the highly filamentary and clumpy structure of the interstellar medium even in diffuse regions of the map. The power spectrum analysis shows that the structure of the interstellar medium is well described by a single power law with an exponent of -2.7±0.1 at all scales from 30” to 8°. That the power spectrum slope of the dust emission is constant down to the SPIRE angular resolution is an indication that the inertial range of turbulence extends down to the 0.01 pc scale. The power spectrum analysis also allows the identification of a Poissonian component at sub-arcminute scales in agreement with predictions of the cosmic infrared background level at SPIRE wavelengths. Finally, the comparison of the SPIRE and IRAS 100 μm data of the Polaris flare clearly assesses the capability of SPIRE in maping diffuse emission over large areas.

This article focuses on the atomic force microscopy-infrared (AFM-IR) technique and its recent technological developments. Based on the detection of the photothermal sample expansion signal, AFM-IR combines the high spatial resolution of atomic force microscopy with the chemical identification capability of infrared spectroscopy to achieve submicrometric physico-chemical analyses. Since the first publication in 2005, technological improvements have dramatically advanced the capabilities of AFM-IR in terms of spatial and spectral resolution, sensitivity, and fields of applications. The goal of this paper is to provide an overview of these developments and ongoing limitations. We summarize recent progress in AFM-IR implementations based on the major AFM contact, tapping, and peak force tapping modes. Additionally, three new trends are presented, namely, AFM-IR applied to mineral samples, in fluid and a novel, purely surface sensitive AFM-IR configuration, to probe top layers. These trends demonstrate the immense potential of the technique and offer a good insight into the scope of AFM-IR.