A Study of Classical Novae Across Differing Stellar Populations

不同恒星族群中经典新星的研究

• 批准号: 0607682
• 负责人: Allen Shafter
• 金额: --
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0607682&HistoricalAwards=false
• 关键词: Study; Classical; Novae; Across; Differing

This project seeks a better understanding of the effects of the underlying stellar population on the formation, evolution, and physical properties of binary systems in general and novae in particular. Towards this end, an observational program will be undertaken to study the spatial distributions and outburst properties of novae in nearby galaxies. While stellar population models predict that the disk components of late-type galaxies should produce more novae than spiral bulges and early type-galaxies (as the disks contain a younger population), observational evidence suggests an equal if not greater novae rate among bulges and elliptical galaxies. If confirmed, these results would be indicative of a failure of population synthesis models as well as a problem with the currently favored model for Type Ia supernovae in which accretion onto massive white dwarfs triggers a thermonuclear runaway - Type Ia supernovae are observed to be more common in disks, i.e., the reverse of what may be true for novae.The observational efforts will be focused along three strategies. First, the true bulge-to-disk ratio of novae in the spiral galaxy M31 and the overall novae rate in the late-type spiral M101 will be determined over the entire spatial extent of the galaxies using the wide field imager on the Steward 90-inch reflector. Second, the maximum brightness and rate of decline of the M31 novae (both in the disk and bulge) will be compared to determine if a radial gradient in speed class exists which would imply two types of novae with properties related to the underlying stellar populations. The necessary light curves will be obtained from follow-up observations at the Mount Laguna Observatory of novae discovered in the wide-field search plus photometry from the Lick Observatory Supernova Search M31 archive and the Robotic Optical Transit Search Experiments. Third, the possibility that the high nova rates for the M13 bulge and M87 (a giant elliptical) are due to nova binaries being generated in globular clusters will be tested by a comparison of nova rates in M49 and M87 - two giant Virgo elliptical galaxies with very different globular cluster populations.The work here is of the relevance to a broad range of astronomy topics - from binary formation to the origins of Type Ia supernovae. Students from the SDSU REU summer program will be directly involved in the work which includes an exciting "discovery" component. Specific tasks include the discovery of novae and measuring the evolution of their optical light curves. SDSU has a large and diverse student population and this project will enhance the research opportunities available to them.

该项目旨在更好地了解底层恒星群对双星系统（特别是新星）的形成、演化和物理特性的影响。为此，将开展一项观测计划来研究附近星系中新星的空间分布和爆发特性。虽然恒星种群模型预测晚型星系的盘组成部分应该比螺旋核球和早型星系产生更多的新星（因为盘中包含更年轻的种群），但观测证据表明核球和椭圆星系之间的新星率相等，甚至更高。如果得到证实，这些结果将表明群体合成模型的失败以及目前流行的 Ia 型超新星模型的问题，其中大质量白矮星的吸积会引发热核失控——观察到 Ia 型超新星在圆盘中更为常见，即与新星的情况相反。观测工作将集中在三种策略上。首先，将使用 Steward 90 英寸反射器上的宽视场成像仪在星系的整个空间范围内确定螺旋星系 M31 中新星的真实核球与盘比以及晚型螺旋 M101 中的总体新星比率。其次，将比较 M31 新星（在圆盘和核球中）的最大亮度和下降率，以确定是否存在速度等级的径向梯度，这意味着两种类型的新星具有与底层恒星群相关的特性。必要的光变曲线将从拉古纳山天文台对宽视场搜索中发现的新星的后续观测以及利克天文台超新星搜索 M31 档案和机器人光学凌日搜索实验的光度测量中获得。 第三，M13核球和M87（一个巨大的椭圆星系）的高新星发生率是否是由于球状星团中生成的新星双星所致，将通过比较M49和M87（两个具有非常不同的球状星团种群的巨大室女座椭圆星系）的新星发生率来测试。这里的工作与广泛的天文学主题相关——从双星形成到起源。 Ia 型超新星。 SDSU REU 暑期项目的学生将直接参与这项工作，其中包括令人兴奋的“发现”部分。具体任务包括发现新星并测量其光变曲线的演变。 SDSU 拥有庞大且多元化的学生群体，该项目将增加他们的研究机会。