From Cool to Ultracool: Investigating Magnetism and Rotation in the Smallest Stars and Ultra Cool Dwarfs

Alejandro Nunez is awarded a Mathematical and Physical Sciences Ascending Postdoctoral Research Fellowship (MPS-Ascend) to conduct a program of research and education at Columbia University. Dr. Nunez plans a rotational and magnetic activity census for 13 open star clusters, using public archives of ground and space-based observatories, complemented with dedicated observations collected during the Fellowship. Based on these observations, he plans a study of the dependence of activity on rotation, paying particular attention to ultra-cool dwarfs, at the different ages of the open clusters to be studied. Dr. Nunez will mentor participants in the Columbia University Bridge to the Ph.D. program.

Dr. Nunez will compare different activity indicators to test competing theories describing magnetic heating of stellar atmospheres. Despite several decades of theoretical and observational efforts, an accurate, quantitative description of the age-rotation-activity relation remains elusive. He seeks to answer several fundamental theoretical questions. He intends to quantify the dependence of rotation and magnetic activity on quantities such as the degree of core-envelope coupling and the magnetic field geometry. For the Bridge to Ph. D. program, his responsibilities will include tracking the progress of participants, gathering feedback, and by organizing activities that foster a sense of community among the participants and that help them in their professional development. He will provide consistent, high-quality, field-specific advising and mentoring to participants.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.