This award will provide partial support for a conference in the area of stellar polarimetry, or the measurement of polarized light from stars or their surroundings. Polarization is the alignment of the orientation of the oscillations of electromagnetic waves (visible light, infrared, radio waves), and is a powerful indicator of physical conditions such as light scattering from grains or population inversions from non-thermal processes. Historically, studies of polarization have not been very popular, mainly because they are somewhat difficult to perform and calibrate, and generally are done best on bright sources. This conference will address current and future directions in polarimetry studies, especially in the context of observations on large telescopes. The discussions will focus on three areas, namely on stellar magnetism, the geometry of light scattering, and the exploration of opacity sources in stellar atmospheres.
. This meeting was a topical meeting that emphasized the use of polarization studies, both the observational and theoretical aspects, to the study of stars. The study of stars is critical to our understanding of the universe. Stars are hosts to planetary systems, they are sites of cosmic recycling of gas, they are tracers of galaxy evolution, and they are examples for some of the most extreme behavior in astrophysics, such as supernova explosions and pulsars. Polarimetry is a technique that refers to a study of the nature of the light from astrophysical sources. In short, polarization from stars is (1) a probe of the geometry of a star and its immediate environment and (2) a probe of opacity sources. Polarization helps astronomers understand the how and why that some stars are not spherical, and it allows astronomers to study these properties without having to resolve the stars and their environments. In other words polarization helps astronomers to "see" the geometry of stars because of the nature of the light without actually being able to get a picture of the system. This in turn is important for understanding how stars form, live, and terminate, as well as the properties of the remnants that stars leave behind. The outcomes of the meeting will be reported in a book. NSF dollars helped nearly 30% of participants to attend the meeting who would otherwise not have been able to attend due to a lack of funding. Topical meetings like this one are important for creating networking opportunities among researchers, particularly younger scientists. Sharing the state-of-the-art results among experts in the field and creating an environment for establishing new collaborations strengthens STEM research in America, particularly in areas of basic research.
