The physical & chemical diagnostics of high mass star formation

物理方面

• 批准号: 249680-2006
• 负责人: Plume, René
• 金额: $ 1.94万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=363810
• 关键词: physical; chemical; diagnostics; mass; star

Over the past 20 years there have been significant advances in the field of star formation. We have determined that all stars are born deeply embedded and emerge over time as the surrounding material is either accreted or dispersed.  We have also learned that the dynamical and physical evolution during the star formation process is accompanied by a strong chemical evolution.  A large part of our progress in the field of star formation has focused solely on the formation of low-mass stars, predominantly because these objects form isolated from other nearby stars, reducing confusion. However, it has now been recognized that most stars, and especially stars more massive than the Sun, do not form in an isolated fashion. Instead, over approximately 90 per cent of all stars form in clusters, in regions which are also forming massive stars. Similar progress in our understanding of the formation of massive stars has been hampered by several factors: a) The greater distances of the Giant Molecular Clouds that are the birth sites of massive stars makes studies of individual objects difficult. b) Contraction timescales for massive stars are much shorter meaning that examples of the earliest phases are rare. c) The very nature of clustered star formation increases the chances for confusion.  As a result, we still do not understand how massive stars form. In this proposal, funding is requested to tackle some of the most pressing issues in the field of massive star formation. Where are the massive star-forming regions in the Galaxy?  How do they form? What determines the upper end of the stellar initial mass function (IMF)? What are the initial conditions for massive star formation? How do the abundances and evolutions of various chemical species differ from those seen in low-mass star forming regions?

在过去的20年里，在星星的形成领域取得了重大进展。我们已经确定，所有的恒星都是深埋在其中，随着周围物质的吸积或分散，随着时间的推移而出现。我们还了解到，星星形成过程中的动力学和物理演化伴随着强烈的化学演化。我们在星星形成领域的很大一部分进展都集中在低质量恒星的形成上，主要是因为这些天体与附近的其他恒星隔离，减少了混乱。然而，现在人们已经认识到，大多数恒星，特别是质量比太阳大的恒星，并不是孤立形成的。相反，大约90%的恒星形成于星团中，这些星团也形成了大质量恒星。在我们对大质量恒星形成的理解中，类似的进展受到以下几个因素的阻碍：a）大质量恒星诞生地巨分子云的距离更远，使得对单个物体的研究变得困难。B）大质量恒星的收缩时间尺度要短得多，这意味着最早阶段的例子很罕见。c）星团星星形成的本质增加了混淆的机会。因此，我们仍然不明白大质量恒星是如何形成的。在这项提案中，要求提供资金，以解决大质量星星形成领域中一些最紧迫的问题。银河系中巨大的恒星形成区在哪里？ 它们是如何形成的？什么决定了恒星初始质量函数（IMF）的上限？大质量星星形成的初始条件是什么？各种化学物质的丰度和演化与低质量星星形成区有何不同？