相关论文: Sub-surface alteration and related change in refle…
The possibility of making an object invisible for detectors has become a topic of considerable interest over the past decades. Most of the studies so far focused on reducing the visibility by reshaping the electromagnetic scattering in the…
New multi-epoch, mid-infrared (8-13 microns) spectrophotometric observations are presented for 30~late-type stars. The observations were collected over a four year period (1994-1997), permitting an investigation of the mid-infrared spectral…
Chemical and mineral compositions of asteroids reflect the formation and history of our Solar System. This knowledge is also important for planetary defence and in-space resource utilisation. We aim to develop a fast and robust…
Oscillatory density profiles (layers) have previously been observed at the free surfaces of liquid metals, but not in other isotropic liquids. We have used x-ray reflectivity to study a molecular liquid, tetrakis(2-ethylhexoxy)silane. When…
Nanoprobe X-ray diffraction (nXRD) using focused synchrotron radiation is a powerful technique to study the structural properties of individual semiconductor nanowires. However, when performing the experiment under ambient conditions, the…
Meteorites contain minerals from Solar System asteroids with different properties (like size, presence of water, core formation). We provide new mid-IR transmission spectra of powdered meteorites to obtain templates of how mid-IR spectra of…
Inaccurate modelling of the near-surface layers of solar models causes a systematic difference between modelled and observed solar mode frequencies. This difference---known as the "surface effect" or "surface term"---presumably also exists…
We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B=10^14-10^15 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property…
Evidence is seen for young, fresh surfaces among Near-Earth and Main-Belt asteroids even though space-weathering timescales are shorter than the age of the surfaces. A number of mechanisms have been proposed to refresh asteroid surfaces on…
Exoplanet atmosphere characterisation has become an important tool in understanding exoplanet formation, evolution. However, clouds remain a key challenge for characterisation: upcoming space telescopes (e.g. JWST, ARIEL) and ground-based…
Most directly imaged giant exoplanets are fainter than brown dwarfs with similar spectra. To explain their relative underluminosity unusually cloudy atmospheres have been proposed. However, with multiple parameters varying between any two…
We present broad band spectra of a sample of 21 low luminosity sources in the Trapezium Cluster, with masses in the range 0.008 - 0.10 Msun (assuming an age of 1 Myr). These were selected for low extinction in most cases and are located…
Exoplanet transmission spectra provide rich information about the chemical composition, clouds and temperature structure of exoplanet atmospheres. Most exoplanet transmission spectra only span infrared wavelengths ($\gtrsim$ 1 $\rm{\mu…
In this work, the influence of crossed magnetic fields (B=100 Gauss) on the UV-vis and NIR spectra and breakdown voltages of nitrogen and oxygen at a pair of parallel plane copper electrodes with a spacing d=2 cm and diameter R= 2.2 cm are…
We analyze the resonant variation of the optical reflection on an infiltrated artificial opal made of transparent nanospheres. The resonant infiltration is considered as a perturbation in the frame of a previously described one-dimensional…
The Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T) program utilizes multiple instruments to provide spectral data over a wide range of temperature and wavelengths. Experimental methods include Vector Network…
In this paper we investigate how the inclusion of scattering of the stellar radiation into a passive flaring disk model affects its structure and spectral energy distribution, and whether neglecting it could significantly decrease the model…
We review recent progress on the modeling and use of reflection spectra from irradiated and ionized accretion discs. On the computational side, calculations of reflection spectra from discs with non-uniform density structure have shown that…
Direct-imaging spectra hold rich information about a planet's atmosphere and surface, and several space-based missions aiming at such observations will become a reality in the near future. Previous spectral retrieval works have resulted in…
We have extended the range of the high-pressure optical spectroscopy to the far-infrared region keeping the accuracy of ambient-pressure experiments. The newly-developed method offers a powerful tool for the study of pressure-induced phase…