AKARI, the first Japanese satellite dedicated to infrared astronomy, was launched on 2006 February 21, and started observations in May of the same year. AKARI has a 68.5 cm cooled telescope, together with two focal-plane instruments, which survey the sky in six wavelength bands from mid–to far-infrared. The instruments also have a capability for imaging and spectroscopy in the wavelength range 2-180$\mu$m in the pointed observation mode, occasionally inserted into a continuous survey operation. The in-orbit cryogen lifetime is expected to be one and a half years. The All-Sky Survey will cover more than 90% of the whole sky with a higher spatial resolution and a wider wavelength coverage than that of the previous IRAS all-sky survey. Point-source catalogues of the All-Sky Survey will be released to the astronomical community. Pointed observations will be used for deep surveys of selected sky areas and systematic observations of important astronomical targets. These will become an additional future heritage of this mission.

The Far-Infrared Surveyor (FIS) is one of two focal plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 µm, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcmin, and the pixel pitch is matches the diffraction limit of the telescope. Derived point spread functions (PSFs) from observations of asteroids are similar to the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and its performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, it can simultaneously make a spectral map. This paper summarizes the in-flight technical and operational performance of the FIS.

The Stark broadening parameters of the 1990.53, 2631.55, 2669.17, 2816.18, 3900.68, and 5593.23 Å lines of Al(II) have been measured in a plasma produced by ablation with a Nd:YAG laser of an aluminum target. In order to obtain suitable experimental conditions for the homogeneity and stability of the plasma a study of the spatial and temporal plasma evolution in helium, argon, and nitrogen at different pressures was made. The broadening parameters were obtained with the aluminum target placed in molecular nitrogen at 1000 mbar, which provides appropriate measurements conditions. The Al(II) 4663.05 Å line was used to determine the electron density in all cases. For this line the Stark shift parameter has been measured. Contributions to broadening arising from mechanism different than Stark broadening were estimated for every studied line.

We report on the initial analysis of a Herschel-PACS full range spectrum of Neptune, covering the 51-220 μm range with a mean resolving power of ∼3000, and complemented by a dedicated observation of CH 4 at 120 μm. Numerous spectral features due to HD (R(0) and R(1)), H 2 O, CH 4 , and CO are present, but so far no new species have been found. Our results indicate that (i) Neptune's mean thermal profile is warmer by ∼3 K than inferred from the Voyager radio-occultation; (ii) the D/H mixing ratio is (4.5 ± 1) × 10 −5 , confirming the enrichment of Neptune in deuterium over the protosolar value (∼2.1 × 10 −5 ); (iii) the CH 4 mixing ratio in the mid stratosphere is (1.5 ± 0.2) × 10 −3 , and CH 4 appears to decrease in the lower stratosphere at a rate consistent with local saturation, in agreement with the scenario of CH 4 stratospheric injection from Neptune's warm south polar region; (iv) the H 2 O stratospheric column is (2.1 ± 0.5) × 10 14 cm −2 but its vertical distribution is still to be determined, so the H 2 O external flux remains uncertain by over an order of magnitude; and (v) the CO stratospheric abundance is about twice the tropospheric value, confirming the dual origin of CO suspected from ground-based millimeter/submillimeter observations.

Context. The first magnetic fields in O-and B-type stars that do not belong to the Bp-star class, have been discovered. The cyclic UV wind-line variability, which has been observed in a significant fraction of early-type stars, is likely to be related to such magnetic fields. Aims. We attempt to improve our understanding of massive-star magnetic fields, and observe twenty-five carefully-selected, OB-type stars. Methods. Of these stars we obtain 136 magnetic field strength measurements. We present the UV wind-line variability of all selected targets and summarise spectropolarimetric observations acquired using the MUSICOS spectropolarimeter, mounted at the TBL, Pic du Midi, between December 1998 and November 2004. From the average Stokes I and V line profiles, derived using the LSD method, we measure the magnetic field strengths, radial velocities, and first moment of the line profiles. Results. No significant magnetic field is detected in any OB-type star that we observed. Typical 1σ errors are between 15 and 200 G. A possible magnetic-field detection for the O9V star 10 Lac remains uncertain, because the field measurements depend critically on the fringe-effect correction in the Stokes V spectra. We find excess emission in UV-wind lines, centred about the rest wavelength, to be a new indirect indicator of the presence of a magnetic field in early B-type stars. The most promising candidates to host magnetic fields are the B-type stars δ Cet and 6 Cep, and a number of O stars. Conclusions. Although some O and B stars have strong dipolar field, which cause periodic variability in the UV wind-lines, such strong fields are not widespread. If the variability observed in the UV wind-lines of OB stars is generally caused by surface magnetic fields, these fields are either weak ( < ∼ few hundred G) or localised.