LEAPS-MPS: A Systematic Investigation of Transient Behavior in RR Lyrae Variable Stars

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。 天琴座RR型星是一类星星，其脉动与其内在光度有着相对直接的关系。因此，这些恒星提供了一个“标准烛光”，用来测量整个星系（甚至到其他星系）的距离。由于它们在整个宇宙中设定距离尺度的作用，在首次描述了机制的大致轮廓之后的几十年里，仍在继续研究天琴座RR型恒星的脉动。这种理解的任何变化都可能对天文学的其他部分产生重大影响。该小组将研究脉动基本模式的振幅变化，沿着其第一泛音，以及这些径向脉动恒星的非径向脉动。他们将进行地面光谱观测，而TESS航天器将对同一颗星星进行光度观测，以便进行实时比较。来自西班牙裔服务机构代表性不足的群体的本科生将参与研究的各个方面。该团队最近发现了双模天琴座星星V338 Boo基本脉动模式振幅的变化。发现基本脉动的振幅以数十天的尺度变化，而第一泛音的振幅保持恒定。此外，其他团队最近发现了非径向脉动，其振幅也在数十天的范围内变化。该团队将观测一组RR-Lyrics恒星，以寻找类似的脉动变化，并将进一步与TESS卫星进行同步观测，以比较实时光谱变化与光度变化。该团队将观测已知的天琴座RR型恒星;对这些模式和变化的研究将为恒星内部的天体物理模型提供信息。该奖项反映了NSF的法定使命，并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，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). RR Lyrae stars are a class of variable star whose pulsations have a relatively straightforward relationship to their intrinsic luminosities. As such, these stars provide a ‘standard candle’ against which to measure distance throughout the galaxy (and even to other galaxies). Because of their role in setting distance scales throughout the universe, pulsations of RR Lyrae stars continue to be studied decades after the broad outline of the mechanism was first described. Any change in that understanding could have significant implications on other parts of astronomy. The team will study changes in the amplitude of the fundamental mode of pulsation, along with its first overtone, as well as non-radial pulsations on these otherwise radially pulsing stars. They will make ground-based spectroscopic observations while the TESS spacecraft conducts photometric observations of the same star, allowing real-time comparison. Undergraduate students, drawn from under-represented groups at a Hispanic Serving Institution, will be involved in all aspects of the research. The team recently discovered changes in the amplitude of the fundamental pulsation mode of the double-mode RR Lyrae star V338 Boo. The fundamental pulsation’s amplitude is found to change on the scale of many tens of days, while the first overtone’s amplitude remains constant. Further, other teams have recently discovered non-radial pulsations whose amplitudes also change on the scale of tens of days. The team will observe a set of RR-Lyrae stars to look for similar changes in pulsations, and will furthermore conduct co-incident observsations with the TESS satellite to compare real-time spectroscopic variations with photometric variations. The team will observe known RR Lyrae stars; the study of these modes and variations will inform astrophysical models of stellar interiors.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.