An Observational Study of Novae in Differing Stellar Populations

不同恒星族中新星的观测研究

• 批准号: 1009566
• 负责人: Allen Shafter
• 金额: $ 28.29万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1009566&HistoricalAwards=false
• 关键词: Observational; Study; Novae; Differing; Stellar

Dr. Allen Shafter will continue his study of the spatial distributions, populations, and outburst properties of novae in selected nearby galaxies. The principal motivation of the study is to acquire a deeper understanding of the effect that the underlying stellar population has on the formation, evolution, and physical properties of close binary systems in general, and novae in particular. Novae are ideally suited to this task because they have high luminosities and can be readily identified in galaxies spanning a wide range of types.Models based on standard nova formation scenarios predict that the disk components of late-type galaxies with their young stellar population component should be more prolific nova producers (i.e., they should have more nova eruptions per unit mass in stars) compared with spiral bulges and early-type galaxies. The available observational evidence, however, seems in conflict with this prediction, with the bulges of spirals and elliptical galaxies appearing to have nova rates as high, or higher, than that seen in younger stellar populations. If confirmed, these results create a problem not only for stellar population models, but for the currently favored model for the progenitors of Type Ia supernovae which are used to determine the expansion rate of the universe.The results of the study will be relevant to a wide range of topics in astronomy, from the formation and evolution of close binary stars such as novae, to their potential role as a progenitor channel for Type Ia supernovae. Students from San Diego State University (SDSU), and from SDSU's Research Experience for Undergraduates (REU) summer program, will be directly involved in the discovery of these novae, in measuring their spectra, and in determining the evolution of their optical light.

艾伦·沙夫特博士将继续研究选定的附近星系中新星的空间分布、数量和爆发特性。这项研究的主要动机是为了更深入地了解底层恒星群对邻近双星系统（特别是新星）的形成、演化和物理性质的影响。新星非常适合这项任务，因为它们具有高光度，并且可以在各种类型的星系中轻松识别。基于标准新星形成情景的模型预测，与螺旋核球和早期型星系相比，晚期型星系的盘成分及其年轻恒星族成分应该是更多产的新星产生者（即，每单位质量的恒星中，它们应该有更多的新星喷发） 星系。然而，现有的观测证据似乎与这一预测相矛盾，螺旋星系和椭圆星系的核球的新星发生率似乎与年轻恒星群中的新星发生率一样高，甚至更高。如果得到证实，这些结果不仅会给恒星种群模型带来问题，也会给目前用于确定宇宙膨胀率的 Ia 型超新星前身模型带来问题。这项研究的结果将与天文学的广泛主题相关，从新星等近距离双星的形成和演化，到它们作为 Ia 型超新星前身通道的潜在作用。来自圣地亚哥州立大学 (SDSU) 和 SDSU 本科生研究体验 (REU) 暑期项目的学生将直接参与这些新星的发现、测量其光谱以及确定其可见光的演化。