Chemical composition of planetary debris disks around white dwarfs

白矮星周围行星碎片盘的化学成分

• 批准号: 203081180
• 负责人: Professor Dr. Klaus Werner
• 金额: --
• 依托单位: Abteilungen Astronomie und Hochenergieastrophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/203081180?language=en
• 关键词: Chemical; composition; planetary; debris; disks

It is known for a long time that the atmospheres of a large fraction of relatively cool white dwarfs (WD) are polluted by metals, suggesting ongoing accretion of circumstellar material. Until recently it was believed that interstellar matter is accreted. But mainly based on the Spitzer discovery of dust disks within the WD tidal disruption radius, it is now commonly accepted that the stars accrete remnant planetary material. The abundance determination of metals in the WD atmosphere offers the exciting possibility to study, though indirectly, the composition of extrasolar planetary material. This requires a good knowledge about accretion and diffusion rates because they transform the abundance pattern of the accreted material in a complicated way. This knowledge, however, can be afflicted with particular uncertainties.Here we propose an alternative and complementary approach. A few “dusty” WDs were recently discovered to also have gaseous metal disks which are interpreted as the grinded remains of dust disk material. The quantitative spectral analysis of these gas disks offers the opportunity to directly measure the composition of the accreting material. To this end we will develop non-LTE models for the gas disks. Preliminary work proved the viability of this approach.

长期以来，人们都知道大部分相对较冷的白矮星（WD）的大气层都受到金属污染，这表明星周物质正在不断吸积。直到最近，人们还相信星际物质是吸积的。但主要基于斯皮策在 WD 潮汐破坏半径内发现的尘埃盘，现在人们普遍认为恒星会吸积残余行星物质。 WD 大气中金属丰度的测定为研究（尽管是间接的）太阳系外行星物质的成分提供了令人兴奋的可能性。这需要对吸积和扩散速率有很好的了解，因为它们以复杂的方式改变吸积材料的丰度模式。然而，这种知识可能会受到特定不确定性的影响。在这里，我们提出了一种替代和补充方法。最近发现一些“尘土飞扬”的WD也有气态金属盘，这些金属盘被解释为尘盘材料的研磨残留物。这些气盘的定量光谱分析提供了直接测量吸积材料成分的机会。为此，我们将为气盘开发非 LTE 模型。初步工作证明了该方法的可行性。

项目成果

The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures

• DOI: 10.1051/0004-6361/201628403
• 发表时间: 2016-07
• 期刊: arXiv: Solar and Stellar Astrophysics
• 作者: S. Hartmann;T. Nagel;T. Rauch;K. Werner

Non-LTE Model Spectra for Gaseous Planetary Debris Disks around WDs

WD 周围气态行星碎片盘的非 LTE 模型光谱

• DOI: 10.1017/s1743921313008867
• 发表时间: 2014
• 期刊: Proceedings of the International Astronomical Union
• 作者: Hartmann;Werner
• 通讯作者: Werner

Non-LTE spectral models for the gaseous debris-disk component of Ton 345

Ton 345 气态碎片盘成分的非 LTE 光谱模型

• DOI: 10.1051/0004-6361/201423690
• 发表时间: 2014
• 期刊: arXiv: Solar and Stellar Astrophysics
• 作者: Hartmann;Werner
• 通讯作者: Werner