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Solar magnetic fields as revealed by Stokes polarimetry
Stenflo, J. O.
Observational astrophysics started when spectroscopy could be applied to astronomy. Similarly, observational work on stellar magnetic fields became possible with the application of spectro-polarimetry. In recent decades there have been dramatic advances in the observational tools for spectro-polarimetry. The four Stokes parameters that provide a c…
Solar flares at submillimeter wavelengths
Krucker, Säm; Kretzschmar, M.; Klein, K. -L. +10 more
We discuss the implications of the first systematic observations of solar flares at submillimeter wavelengths, defined here as observing wavelengths shorter than 3 mm (frequencies higher than 0.1 THz). The events observed thus far show that this wave band requires a new understanding of high-energy processes in solar flares. Several events, includ…
Supernova remnants: the X-ray perspective
Vink, Jacco
Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And in particular the advances made in X-ray imaging s…
The origin of the Martian moons revisited
Rosenblatt, Pascal
The origin of the Martian moons, Phobos and Deimos, is still an open issue: either they are asteroids captured by Mars or they formed in situ from a circum-Mars debris disk. The capture scenario mainly relies on the remote-sensing observations of their surfaces, which suggest that the moon material is similar to outer-belt asteroid material. This …
Morphology, dynamics and plasma parameters of plumes and inter-plume regions in solar coronal holes
Llebaria, A.; Auchère, F.; Feng, L. +12 more
Coronal plumes, which extend from solar coronal holes (CH) into the high corona and—possibly—into the solar wind (SW), can now continuously be studied with modern telescopes and spectrometers on spacecraft, in addition to investigations from the ground, in particular, during total eclipses. Despite the large amount of data available on these promi…
The quest for the solar g modes
Baudin, F.; García, R. A.; Provost, J. +18 more
Solar gravity modes (or g modes)—oscillations of the solar interior on which buoyancy acts as the restoring force—have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well-observed acoustic modes (or p modes). The relative high amplitude of the g-mode eigenfu…
X-ray absorption and reflection in active galactic nuclei
Turner, T. J.; Miller, L.
X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei (AGN), and to learn about the accretion process that fuels AGN and the feedback of material to their host galaxies. We describe the spectral signatures that may be studied and review the …
Results from the Huygens probe on Titan
Strobel, Darrell; Coustenis, Athena; Lebreton, Jean-Pierre +3 more
The Cassini-Huygens mission, comprising the NASA Saturn Orbiter and the ESA Huygens Probe, arrived at Saturn in late June 2004. The Huygens probe descended under parachute in Titan's atmosphere on 14 January 2005, 3 weeks after separation from the Orbiter. We discuss here the breakthroughs that the Huygens probe, in conjunction with the Cassini sp…
A review of Titan's atmospheric phenomena
Sotin, Christophe; Le Mouélic, Stéphane; Tokano, Tetsuya +2 more
Saturn’s satellite Titan is a particularly interesting body in our solar system. It is the only satellite with a dense atmosphere, which is primarily made of nitrogen and methane. It harbours an intricate photochemistry, that populates the atmosphere with aerosols, but that should deplete irreversibly the methane. The observation that methane is n…
Sixty-five years of solar radioastronomy: flares, coronal mass ejections and Sun Earth connection
Vilmer, Nicole; Pick, Monique
This paper will review the input of 65 years of radio observations to our understanding of solar and solar terrestrial physics. It is focussed on the radio observations of phenomena linked to solar activity in the period going from the first discovery of the radio emissions to present days. We shall present first an overview of solar radio physics…