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

Alejandro Nunez被授予数学和物理科学上升博士后研究奖学金(MPS-Ascend)，以在哥伦比亚大学开展研究和教育项目。努涅斯博士计划对13个开放星团进行一次旋转和磁性活动普查，使用地面和天基天文台的公共档案，并辅之以在联谊会期间收集的专门观测数据。在这些观测的基础上，他计划对活动与自转的依赖关系进行研究，特别关注待研究疏散星系团不同年龄的超冷矮星。努涅斯博士将指导哥伦比亚大学攻读博士项目的学员。努涅斯博士将比较不同的活动指标，以检验描述恒星大气磁热的相互竞争的理论。尽管经过了几十年的理论和观测努力，但对年龄-旋转-活动关系的准确、定量描述仍然难以捉摸。他试图回答几个基本的理论问题。他打算量化旋转和磁活动对诸如核-包层耦合程度和磁场几何形状等量的依赖。对于博士之桥项目，他的职责将包括跟踪参与者的进展，收集反馈，并通过组织活动在参与者中培养社区意识，帮助他们的专业发展。他将为参与者提供一致的、高质量的、特定领域的建议和指导。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.