Travis Metcalfe is an astronomer who probes the interiors of distant, Sun-like stars to improve understanding of stellar structure and shed light on the behavior of our own Sun. He combines astronomical theory, computer science, and the few measurements available to piece together a portrait of magnetic plasma movement and other interior processes. For data, he relies on sound waves, or pulsation frequencies, that traverse the interiors of Sun-like stars and rise to the surface. Metcalfe has a cross-laboratory appointment in NCAR's High Altitude Observatory (ESSL) and Scientific Computing Division (CISL).

Colloquium: Travis Metcalfe (Host: Jason Jackiewicz)

When:
September 8, 2017 @ 3:15 pm – 4:15 pm
2017-09-08T15:15:00-06:00
2017-09-08T16:15:00-06:00
Where:
BX102

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.


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