Conveners
Polarization and stars
- Gianpiero Tagliaferri (INAF / Brera Astronomical Observatory)
Polarization and stars
- Gianpiero Tagliaferri (INAF / Brera Astronomical Observatory)
Polarization and stars
- Gianpiero Tagliaferri (INAF / Brera Astronomical Observatory)
This talk presents a revision of the literature relative to optical polarimetric measurements of cataclysmic variables (CVs). It is briefly introduced this kind of objects and the historical relevance of the detection of circular polarization in magnetic CVs. It is then discussed how polarization can be used to estimate important properties of those objects as the white-dwarf magnetic field,...
Magnetic fields can be found at the surface of non-degenerate stars all over the HR diagram. Their nature is split between those contemporaneously generated by dynamo mechanism (e.g. low mass MS stars) and those of fossil origins (e.g. high mass MS stars). This means that there are fundamental differences in their observed properties — for example, while magnetic fields of low-mass stars are...
Massive stars in WR+O systems are in a unique phase of their evolution; their strong and dense winds are thought to significantly affect their future evolution into GRBs, SNe, and ultimately inspiraling compact objects. Our team is carrying out an observational spectropolarimetric study of southern, WR+O star, colliding wind binaries to characterize their shock and wind structures using the...
Accretion-powered relativistic jets are a ubiquitous element of systems with accreting black holes. Despite the ubiquity of these jets, we have yet to construct a complete picture of the underlying mechanisms that control their evolution. In these jets, synchrotron emission leads to partial linear polarization, with fractional polarization levels and polarization angles that depend on the...
About 10% of the known massive stars have strong, dipolar magnetic fields. Magnetohydrodinamical simulations show that the combination of strong magnetic fields and fast rotation can lead to the formation of co-rotating magnetospheres around these objects.
A theoretical model (the Ridigly Rotating Magnetosphere model, RRM) is available for the case of very strong magnetic fields. This model...
Massive stars are characterized by their intense luminosities and powerful, radiatively driven stellar winds. About 7% of massive stars also host strong (~1 kG), global magnetic fields, with stable, nearly dipolar magnetic topologies. These fields channel the stellar wind into a complex magnetosphere which has a significant impact on the star’s evolution. It is therefore critical to measure...
Although > 6% of isolated massive stars are magnetic, a magnetic field is rarely observed (<1.5%) in the case of close hot binaries. Among them, $\epsilon$ Lupi A is the only close hot binary where both the components are magnetic. The stars have anti-aligned dipoles pointing to interacting magnetic fields, and orbit close enough that their magnetospheres are predicted to overlap, leading to...
