High spatial resolution mid-infrared observations of the low-mass young star TW Hydrae
High spatial resolution mid-infrared observations of the low-mass young star TW Hydrae
复制标题
低质量年轻恒星 TW Hydrae 的高空间分辨率中红外观测
DOI：
10.1051/0004-6361:20077357
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
W. Jaffe
中科院分区：
文献类型：
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作者：
T. Ratzka;C. Leinert;T. Henning;J. Bouwman;C. Dullemond;W. Jaffe
目标。我们想要改善对附近TTauri星TW Hya周围的恒星周圆盘内部少数AU的结构的了解。早些时候的研究表明，存在一个巨大的内洞，可能是由于与不断增长的原行星的相互作用造成的。方法：研究方法。我们使用了利用甚大望远镜干涉仪上的MIDI仪器在N波段获得的干涉观测，以及由红外线卫星Spitzer记录的10微米光谱。我们能够确定这个相对较暗的源的N波段相关通量和可见度这一事实表明，中红外干涉测量可以应用于大量低质量的年轻恒星物体。结果。用Spitzer获得的中红外光谱显示了HI(6-5)、HI(7-6)和[Ne II]的发射线，并表明在这个波长范围内我们看到的尘埃中90%以上是无定形的。根据MIDI测量的相关通量，大部分结晶物质位于圆盘内部未溶解的部分，半径约为1AU。能见度排除了早期模型所要求的在TWHYA的星周盘中存在一个非常大的(3−4AU半径)内洞的可能性。相反，我们提出了一种内盘的几何形状，其中内孔仍然存在，但半径大大减小，从零到全盘高度的过渡在0.5AU到0.8AU之间，并且内部的尘埃分布非常薄。这样的模型可以符合SED和中红外能见度，以及在近红外2微米处观察到的能见度和扩展发射。如果像推测的那样，一个大质量行星是造成这个内洞的原因，那么它的轨道距离恒星的距离必须比0.3AU更近。或者，我们可能正在见证吸积阶段的结束，以及星盘由内向外扩散的早期阶段。
Aims. We want to improve knowledge of the structure of the inner few AU of the circumstellar disk around the nearby T Tauri star TW Hya. Earlier studies have suggested the existence of a large inner hole, possibly caused by interactions with a growing protoplanet. Methods. We used interferometric observations in the N-band obtained with the MIDI instrument on the Very Large Telescope Interferometer, together with 10 µm spectra recorded by the infrared satellite Spitzer. The fact that we were able to determine N-band correlated fluxes and visibilities for this comparatively faint source shows that mid-infrared interferometry can be applied to a large number of low-mass young stellar objects. Results. The mid-infrared spectra obtained with Spitzer reveal emission lines from H I (6–5), H I (7–6), and [Ne II] and show that over 90% of the dust we see in this wavelength regime is amorphous. According to the correlated flux measured with MIDI, most of the crystalline material is in the inner, unresolved part of the disk, about 1 AU in radius. The visibilities exclude the existence of a very large (3−4 AU radius) inner hole in the circumstellar disk of TW Hya, which was required in earlier models. We propose instead a geometry of the inner disk where an inner hole still exists, but at a much reduced radius, with the transition from zero to full disk height between 0.5 and 0.8 AU, and with an optically thin distribution of dust inside. Such a model can comply with SED and mid-infrared visibilities, as well as with visibility and extended emission observed in the near-infrared at 2 µm. If a massive planet was the reason for this inner hole, as has been speculated, its orbit would have to be closer to the star than 0.3 AU. Alternatively, we may be witnessing the end of the accretion phase and an early phase of an inward-out dispersal of the circumstellar disk.
DOI：
10.1086/429658
发表时间：
2005-02
期刊：
The Astrophysical Journal
影响因子：
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作者：
Hidekazu Tanaka;Youhei Himeno;S. Ida
通讯作者：
Hidekazu Tanaka;Youhei Himeno;S. Ida