Extragalactic Distance Measurements with Planetary Nebulae_

利用行星状星云进行河外距离测量_

• 批准号: 9119554
• 负责人: Robin Ciardullo
• 金额: $ 6.36万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1995-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9119554&HistoricalAwards=false
• 关键词: Extragalactic; Distance; Measurements; Planetary; Nebulae_

It is common to think of using the brightest stars to determine extragalactic distances. Over 50 years ago Hubble first attempted to resolve stars in other galaxies to quantify the expansion of the universe, and since then, the use of blue and red supergiants for extragalactic distance determinations has been explored several times. However, only recently has it been appreciated that young planetary nebulae also fall into the "brightest stars" category and are therefore potentially useful as distance indicators. The central stars of these objects are almost as luminous as bright red supergiants, and, as a result, present telescopes and current technology allow planetary nebulae to be detected at distances as large as 25 megaparsecs. Planetary nebulae have several advantages over most other extragalactic distance indicators. Because they are not associated with any one stellar population they can be found in all types of galaxies, and are particularly valuable for probing elliptical galaxies. It is elliptical galaxies which define the cores of large groups and clusters. In this grant surveys of planetary in elliptical galaxies will be made out to a distance of 25 megaparsecs. These measurements will add to our understanding of the large scale motions of galaxies and in other studies. The Principal Investigator is a recognized expert in this research area.

人们普遍认为使用最亮的恒星来确定河外距离。 50多年前，哈勃首次尝试解析其他星系中的恒星来量化宇宙的膨胀，从那时起，使用蓝色和红色超巨星来确定河外距离的方法已经被多次探索。 然而，直到最近人们才认识到，年轻的行星状星云也属于“最亮的恒星”类别，因此可能可用作距离指示器。 这些天体的中心恒星几乎与亮红色超巨星一样明亮，因此，现有的望远镜和当前的技术允许在长达 25 兆秒差距的距离处探测到行星状星云。 与大多数其他河外距离指示器相比，行星状星云有几个优点。 由于它们与任何一种恒星群都不相关，因此可以在所有类型的星系中找到它们，并且对于探测椭圆星系特别有价值。 椭圆星系定义了大型星系团和星团的核心。 在这项拨款中，对椭圆星系中行星的调查将在 25 兆秒差距的距离内进行。 这些测量将增进我们对星系大尺度运动和其他研究的理解。 首席研究员是该研究领域公认的专家。