SDO, the Sun, the Universe
Dean Pesnell, NASA / GSFC
ABSTRACT: The Sun is our best example for how stars evolve and behave. It is the only star whose surface is well-resolved in time and space. It is the only star which local helioseisomology can look into and through. One tool we to study the Sun is the Solar Dynamics Observatory (SDO), a NASA satellite that has been returning data for seven years. SDO focuses on the variations in the Sun caused by changes in the magnetic field generated by the convection zone.I will describe some aspects of SDO science that can be directly related to Sun-like stars. First are spectral irradiance measurements in extreme ultraviolet wavelengths that contribute to the loss of planetary atmospheres. Next are failed filament eruptions that fall back onto the surface as a form of accretion. Finally, how the magnetic field evolves from solar minimum to maximum and back is giving us clues about predicting that magnetic field. Please come and have a look at how studying the Sun informs our knowledge of stars.
Characterizing the oscillatory response of the chromosphere during solar flares
Laurel Farris; NMSU Astronomy Department
Quasi-periodic pulsations (QPPs) are observed in the emission of solar flares over a wide range of wavelengths,
particularly in the radio and hard x-ray regimes where non-thermal emission dominates. These pulsations are
considered to be an intrinsic feature of flares, yet the exact mechanism that triggers them remains unclear.
There have been reports of an increase in the oscillatory power at 3-minute periods (the local acoustic
cutoff frequency) in the solar chromosphere associated with flaring events. I propose to investigate the
chromospheric response to flares by inspecting the spatial and temporal onset and evolution of the 3-minute
oscillatory power, along with any QPP patterns that may appear in chromospheric emission. The analysis
will be extended to multiple flares, and will include time before, during, and after the main event. To test
initial methods, the target of interest was the well-studied 2011 February 15 X-class flare. Data from two
instruments on board the Solar Dynamics Observatory (SDO) were used in the preliminary study, including
continuum images from the Helioseismic and Magnetic Imager (HMI) and UV images at 1600 and 1700
Angstroms from the Atmospheric Imaging Assembly (AIA). Later, spectroscopic data from the Interface
Region Imaging Spectrometer (IRIS) will be used to examine velocity patterns in addition to intensity.
Multi-pronged investigations into exoplanetary magnetic fields
Wilson Cauley (Arizona State University)
Efforts in exoplanet characterization have led to some very precise determinations of planetary densities, compositions, and even accurate maps of active region and spot locations on stellar surfaces. Exoplanet magnetic fields, however, remain elusive. While radio observations continue to push into the low-mass brown dwarf regime, no emission from a planetary-mass object has been confirmed. I will discuss some of the efforts involving alternate methods for probing exoplanet magnetic fields and how they stack up so far against the prospects for detection via radio emission.
The Circumstellar Disks and Binary Companions of Be Stars
Drew Chojnowski, NMSU
Tremendous progress has been made over the past two decades toward understanding Be stars, but a number of key aspects of them remain enigmatic. The unsolved mysteries include identification of the mechanism responsible for disk formation, the reason this mechanism occasionally turns off or on unexpectedly, the source of viscosity in the circumstellar disks, and the cause of slowly precessing density perturbations in the disks of many or most Be stars. On a deeper level, the origin of Be stars’ near-critical rotation is unknown, with one possible explanation being spin-up due to interaction with a binary companion. A better understanding of these stars is needed, with a particular focus on high-mass binaries being warranted in the age of gravitational wave astronomy. In this dissertation, I will extend the knowledge and understanding of Be stars through a series of three projects. First, I will present and describe the largest ever homogeneous, spectroscopic sample of Be stars to date. I will then focus on investigation of a rare class of Be stars found in binary systems with hot, low mass companions. The second project will present detailed characterization and modeling of HD~55606, a newly discovered member of this class. Finally, I will discuss the results of spectroscopic monitoring of seven newly discovered systems and establish or place limits on the orbital parameters of the binary components.
SHINE: code for everything
Tim Fitzpatrick, Artist, Scotland
SHINE, ’Code for Everything’ is an on-going art work by Tim Fitzpatrick in collaboration with astronomer Anne-Marie Weijmans of the School of Physics and Astronomy at the University of St Andrews. The art takes its inspiration from the Anne-Marie’s work and the science of spectroscopy and, in particular, through a series of visual and experimental representations of the individual emission spectra of the elements.
Tim Fitzpatrick’s principal development of the work is through his fascination with the extraordinary level of detail – and therefore information – contained in the spectrum of starlight. As the work progresses and evolves he seeks to develop the theme of the linguistics of the light of the elements and, by extension, our reading of the light of the universe and our place in it, as described in a series of codes.