Anne-Marie Broomhall: Recent Advances in Helio- and Asteroseismology
Speaker: Anne-Marie Broomhall
Helioseismology uses the Sun's natural acoustic oscillations to study the Sun's interior. Asteroseismology applies similar principles and techniques to use a star's natural resonant oscillations to characterise that star. Here I consider the asteroseismology of solar-like stars, whose oscillations are excited by turbulent outer convective regions. I will draw comparisons between helioseismic and asteroseismic data. In particular I will discuss the impact of solar and stellar magnetic fields on the properties of helio- and asteroseismic data. The Sun's magnetic activity cycle is particularly topical at the moment as it has recently been behaving unexpectedly: The solar activity minimum, observed between 2006 and 2010, lasted significantly longer than expected. The strength of the Sun's magnetic field has now, once again, increased and we are currently at or close to the maximum of solar cycle 24. However, even this cycle is unusual for recent times as its peak is smaller than any cycle observed since the early 1900s. I will show that the helioseismic data indicate that the solar interior displayed unusual behaviour well before the recent minimum. It is well known that violent eruptions associated with the Sun's magnetic activity cycle can impact life on Earth in the form of space weather. Asteroseismic studies of stellar activity are vital both for putting the Sun's activity cycle in a broader, stellar context, and for determining the habitability of any exoplanets.