The Magnetic Mid-life Crisis of the Sun
Dr. Travis Metcalfe, Space Sciences Institute
After decades of effort, the solar activity cycle is exceptionally well characterized but it remains poorly understood. Pioneering work at the Mount Wilson Observatory demonstrated that other sun-like stars also show regular activity cycles, and suggested two possible relationships between the rotation rate and the length of the cycle. Neither of these relationships correctly describe the properties of the Sun, a peculiarity that demands explanation. Recent discoveries have started to shed light on this issue, suggesting that the Sun’s rotation rate and magnetic field are currently in a transitional phase that occurs in all middle-aged stars. We have recently identified the manifestation of this magnetic transition in the best available data on stellar cycles. The results suggest that the solar cycle may be growing longer on stellar evolutionary timescales, and that the cycle might disappear sometime in the next 0.8-2.4 Gyr. Future tests of this hypothesis will come from ground-based activity monitoring of Kepler targets that span the magnetic transition, and from asteroseismology with the TESS mission to determine precise masses and ages for bright stars with known cycles.
NASA, Exoplanets, and Life After NMSU
Dawn Gelino, NASA Exoplanet Science Institute, CalTech
Abstract: Are you interested in learning more about the search for life in the Universe? Or perhaps you may be interested in being awarded time on 10 m telescopes for your science? Or maybe you are ready to learn more about prestigious NASA Postdoctoral Fellowships? This talk will touch on some recent and exciting results in the exoplanet field, as well as the different NASA HQ programs that I currently run for all of astrophysics (many of which may be helpful and applicable to YOU), and the path I took from NMSU to where I am now.
Stellar Winds and Stellar Rotation
Don Terndrup, Ohio State University
For more than 50 years, we have known that stars rotate quickly when they are young and slow down as they age. This process gives us important clues about magnetic field strength and geometry, as well as the nature of stellar winds, in solar-like stars. We have been working to put the analysis of stellar rotation on a modern statistical footing, and in this talk I will give you an update on our efforts. There are a number of critical observational problems that must be considered in calibrating models of angular momentum loss, especially problems of data censorship (older or less active stars are not detected in studies of rotation). I will conclude by evaluating the prospects for using stellar rotation as an age indicator, and demonstrate that such ages are far less precise – though still useful – than our group and others have previously claimed.