Understanding subdwarf B stars through asteroseismology

通过星震学了解亚矮星 B 星

• 批准号: 0307480
• 负责人: Michael Reed
• 金额: $ 29.15万
• 依托单位: Missouri State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0307480&HistoricalAwards=false
• 关键词: Understanding; subdwarf; stars; through; asteroseismology

AST 0307480PI ReedAfter decades of progress in both stellar evolution theory and observational stellar astronomy, the late stages of evolution of most of the stars in our Galaxy - stages in which they shed their outer envelopes and expose their compact cores - conceal many still-unanswered questions. Recently, we have begun to exploit a powerful tool, astroseismology, for probing the interiors of stars and modeling their structure from oscillations and pulsations of the stars. Subdwarf B (sdB) stars are evolved stars located on the so-called horizontal branch of the Hertzsrung-Russell diagram, and they are thought to be the precursors of low mass white dwarf stars. Their progenitors are stars like our Sun. To date, the observational emphasis has been on discovering new pulsating sdB stars. With over 30 members discovered, the field is now mature enough to turn the success we have enjoyed applying astroseismology of white dwarfs to sdB stars. To do so requires that sufficient photometric data be obtained to resolve the often complex pulsation structure of individual objects. As horizontal branch stars, sdB stars are burning helium in their cores, With their limited hydrogen envelopes, these stars have no shell hydrogen burning simplifying their structure, and making them easier to model. Thus far only a few pulsating sdB stars have resolved pulsation spectra, some of which have revealed very interesting results. The goal of this research is to fully apply the tools of astroseismology to sdB stars by resolving the pulsation spectra of several additional members. This requires substantial telescope time to be split between national facilities, Baker Observatory (operated by our home institution), and multi-site observational campaigns with international collaborators. Pulsating stars may also be used to look for planets. Companions to sdB stars can be detected as periodic variations in the pulsation phases. Such measurements are readily sensitive to sub-Jupiter mass planets with long periods. Broader impacts. Undergraduate students will assist in obtaining and reducing the data in this research project. By exposing undergraduate students to research, they are better able to decide if astronomy is the correct career path for them. Additionally, it allows Southwest Missouri State's students to competitively apply for graduate programs based on a strong undergraduate research experience.

AST 0307480PI Reed经过数十年恒星演化理论和观测恒星天文学的进展，我们银河系中大多数恒星的演化后期阶段——它们脱落外层外壳并暴露其致密核心的阶段——隐藏了许多尚未解答的问题。最近，我们开始利用一种强大的工具——星震学，来探测恒星的内部，并根据恒星的振荡和脉动对其结构进行建模。亚矮星 B (sdB) 星是位于赫罗图水平分支上的演化恒星，它们被认为是低质量白矮星的前身。它们的祖先是像我们的太阳一样的恒星。迄今为止，观测的重点一直是发现新的脉动 sdB 恒星。随着发现了 30 多个成员，该领域现在已经足够成熟，可以将我们所享受的将白矮星星震学应用于 sdB 恒星的成功。为此，需要获得足够的光度数据来解析单个物体通常复杂的脉动结构。作为水平分支恒星，sdB恒星在其核心燃烧氦气，由于其有限的氢包层，这些恒星没有壳层氢燃烧，从而简化了它们的结构，并使它们更容易建模。 迄今为止，只有少数脉动 sdB 恒星解析出了脉动光谱，其中一些已经揭示了非常有趣的结果。这项研究的目标是通过解析其他几个成员的脉动谱，将天震学工具充分应用于 sdB 恒星。这需要将大量的望远镜时间分配给国家设施、贝克天文台（由我们所在机构运营）以及与国际合作者进行的多地点观测活动。脉动恒星也可用于寻找行星。 sdB 恒星的伴星可以通过脉动相位的周期性变化来检测。这种测量对于长周期的亚木星质量行星很敏感。更广泛的影响。 本科生将协助获取和减少本研究项目中的数据。通过让本科生接触研究，他们能够更好地确定天文学是否是他们正确的职业道路。此外，它还使西南密苏里州立大学的学生能够凭借丰富的本科研究经验竞争性地申请研究生课程。