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We investigate the linear polarization produced by interstellar dust aligned by the magnetic field in the solar neighborhood (d< 50 pc). We also look for intrinsic effects from circumstellar processes, specifically in terms of polarization variability and wavelength dependence. We aim to detect and map dust clouds which give rise to statistically significant amounts of polarization of the starlight passing through the cloud, and to determine the interstellar magnetic field direction from the position angle of the observed polarization. High-precision broad-band (BVR) polarization observations are made of 361 stars in spectral classes F to G, in the magnitude range 4-9, with detection sensitivity at the level of or better than 10E-5 (0.001 %). Statistically significant (>3 sigma) polarization is found in 115 stars, and > 2 sigma detection in 178 stars, out of the total sample of 361 stars. Polarization maps based on these data show filament-like patterns of polarization position angles which are related to both the heliosphere geometry, the kinematics of nearby clouds, and the Interstellar Boundary EXplorer (IBEX) ribbon magnetic field. From long-term multiple observations, a number (18) of stars show evidence of intrinsic variability at the 10E-5 level. This can be attributed to circumstellar effects (e.g., debris disks and chromospheric activity). The star HD 101805 shows a peculiar wavelength dependence, indicating size distribution of scattering particles different from that of a typical interstellar medium.
Signals from radio pulsars show a wavelength-dependent delay due to dispersion in the interstellar plasma. At a typical observing wavelength, this delay can vary by tens of microseconds on five-year time scales, far in excess of signals of interest t
In the mapping of the local ISM it is of some interest to know where the first indications of the boundary of the Local Bubble can be measured. The Hipparcos distances combined to B-V photometry and some sort of spectral classification permit mapping
Similar directions are obtained for the local interstellar magnetic field (ISMF) by comparing diverse data and models that sample five orders of magnetic in spatial scales. These data include the ribbon of energetic neutral atoms discovered by the In
Starlight that becomes linearly polarized by magnetically aligned dust grains provides a viable diagnostic of the interstellar magnetic field (ISMF). A survey is underway to map the local ISMF using data collected at eight observatories in both hemis
Debris discs are typically revealed through excess emission at infrared wavelengths. Most discs exhibit excess at mid- and far-infrared wavelengths, analogous to the solar systems Asteroid and Edgeworth-Kuiper belts. Recently, stars with strong (1 pe