Calibrating Stellar Gyrochronology Using Improved Rotation Period Measurements

恒星自转提供了一个有希望的，但有缺陷的方法来测定恒星的年龄。最近对疏散星团旋转的调查显示，自旋下降会停滞很长一段时间，其持续时间随着恒星质量的降低而增加。这一研究方案将改进低质量恒星（太阳质量的40-130%）的基于旋转的年龄测定技术，方法是用一个现代化的、扩大的基准星星团旋转周期测量数据库校准“陀螺年代学”。 PI是哥伦比亚大学博士桥梁的创始人。在STEM项目中。 12年来，桥梁计划增加了进入STEM博士学位的代表性不足的学者的数量。计划，并装备他们在这些计划取得成功。 一位桥梁学者将在这个研究项目中发挥主导作用，并得到团队中资深研究人员的精心指导。该项目将通过检查TESS观测到的附近和年轻的疏散星团和移动集团（50-500百万年）来确定恒星何时会聚在慢序上。接下来，开普勒，K2和PTF数据的老集群（1 Gyr）将进行分析，以限制失速的时间尺度和随后的自旋下降率。这将为一个新的经验模型提供信息，该模型将描述在不同质量的恒星中观察到的所有自旋下降阶段。最后，金属丰度对旋转演化的影响将使用一组同时代但化学性质不同的集群进行测试。例如，NGC 6866的旋转周期分布将使用开普勒数据，Coma Ber使用TESS数据。这些序列将与Praesepe和Hyades的序列进行比较，它们大约是同时代的（都是~ 7亿年），但金属丰度比目标星团丰富0.2 dex。确定这种金属丰度的敏感性对于推断场星精确的基于旋转的年龄至关重要。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Stellar rotation provides a promising, yet flawed means for age-dating stars. Recent surveys of rotation in open clusters revealed that spin-down stalls for an extended period of time, the duration of which increases toward lower stellar masses. This research program will improve rotation-based age-dating techniques for low-mass stars (40-130% of the Sun's mass) by calibrating “gyrochronology” with a modern, expanded database of rotation period measurements for benchmark star clusters. The PI is the founder of the Columbia University Bridge to the Ph.D. in STEM Program. For twelve years, the Bridge program has increased the number of underrepresented scholars entering STEM Ph.D. programs and to equip them to succeed in these programs. A Bridge scholar will play a leading role in this research program, with careful mentoring from the senior researchers on the team.The project will determine when stars converge on the slow sequence by examining nearby and young open clusters and moving groups observed by TESS (50-500 Myr). Next, Kepler, K2, and PTF data for older clusters (1 Gyr) will be analyzed to constrain the stalling timescale and the subsequent rate of spin-down. This will inform a new empirical model that will describe all the observed phases of spin-down in stars of different masses. Finally, the impact of metallicity on rotational evolution will be tested using sets of coeval but chemically different clusters. For example, rotation period distributions will be produced for NGC 6866 using Kepler data, and Coma Ber using TESS data. These sequences will be compared to those for Praesepe and the Hyades, which are approximately coeval (all ~700 Myr) but are 0.2 dex richer in metallicity than the target clusters. Determining this sensitivity to metallicity is critical for inferring accurate rotation-based ages for field stars.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.