Modeling of the outer atmosphere of cool stars based on the ISO spectroscopy

基于 ISO 光谱的冷恒星外层大气建模

• 批准号: 11640227
• 负责人: TSUJI Takeshi
• 金额: $ 2.24万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640227/
• 关键词: ISO; infrared spectra; red supergiants; red giants; brown dwarfs; Molecular Sphere; dust cloud; non-gray model photosphere; M型巨星; K型巨星; 褐色彗星; 非灰色大気モデル; 色-等級図11-43; 水分子; ダスト; M型矮星; 光球; 彩層; 恒星風; ISO(Infrared Space Observatory); 早期M型超巨星 /

1. From the analysis of ISO SWS spectra, supplemented with those from the ISO data archive, we show that water exists throughout red (super)giants including K giant a Tau (Aldebaran), early M supergiants a Ori (Betelgeuse) & μ, Cep, and all the M 'giants of MOIII - M9III Water was discovered in α Ori & μ Cep nearly 40 years ago by the pioneering space mission with Stratoscope II, but this important discovery was so unexpected at that time (and even today) that it has been misinterpreted and overlooked for a long time. We rediscovered this unexpected phenomenon and extended it to a larger sample of cool luminous stars. The excitation temperatures of the water bands are rather high (T_<ex> 【approximately equal】 1800K) and water appears in emission in μ, Cep as well as in late M giants. This finding is difficult to understand by the presently known models and/or theories on stellar atmospheres, and we propose instead the presence of a warm molecular sphere (MOLsphere) as the 4-th componen … More t of the stellar atmosphere consisting of the photosphere, chromosphere, and expanding cool wind. How to understand the origin of the MOLsphere and its physical structure should be a challenge to the theory of 'stellar atmosphere.2. We observed some spectra of M dwarfs by ISO, but we must wait for the next infrared missions such as Astro-F (ISAS) and SIKTF (NASA) to observe the spectra of brown dwarfs. To provide physical basis of interpreting the infrared spectra of cool dwarfs including M-type and brown dwarfe, we developed model photospheres of cool dwarfe, in which formation of dust cloud plays a crucial role. Based on a simple thermodynamical argument, we proposed unified cloudy model (UCM) in which dust can be sustained in the temperature range between the condensation temperature (T_<cond> 【approximately equal】 2000K) and the critical temperature・ (T_<cr> 【approximately equal】 1800K), independently of T_<eff>. Then, the dust cloud appears in the optically thin region in L dwarfe whose Teff are relatively high but will sink below the observable photosphere in the cooler T dwarfe. The observed CM diagram, SED, and spectra are well reproduced with our UCMs consistently throughout L to T dwarfe. This fact in turn can be regarded as an observational confirmation of our model of the cloud formation. We hope that our UCM will be of some clue for modeling the atmospheres of extrasolar giant planets. Less

1. From the analysis of ISO SWS spectra, supplemented with those from the ISO data archive, we show that water exists throughout red (super)giants including K giant a Tau (Aldebaran), early M supergiants a Ori (Betelgeuse) & μ, Cep, and all the M 'giants of MOIII - M9III Water was discovered in α Ori & μ Cep almost 40 years ago by the通过Stratocsope II开创了空间任务，但是当时（甚至在今天），这一重要发现是如此出乎意料，以至于它已经被误解和忽视了很长时间。我们重新发现了这种意外的现象，并将其扩展到了更大的凉爽恒星样品。水带的兴奋温度相当高（T_ <ex> [大约等于] 1800K），并且水在μ，CEP以及晚期的巨人中出现。目前已知的模型和/或理论很难理解这一发现，而我们提出了一个温暖的分子球（Molsphere）作为第4-构成……更多的恒星大气，包括光球，彩色，铬球和膨胀的凉风。如何理解摩尔斯球的起源及其物理结构应该是对恒星大气理论的挑战。2。我们观察到ISO的一些M矮人光谱，但是我们必须等待下一个红外任务，例如Astro-F（ISAS）和Siktf（NASA），以观察棕色矮人的光谱。为了提供解释包括M型和棕色矮人在内的凉爽矮人的红外光谱的物理基础，我们开发了凉爽矮人的模型照片，其中尘埃云的形成起着至关重要的作用。基于一个简单的热力学论证，我们提出了统一的云模型（UCM），其中粉尘可以在冷凝温度（T_ <cond> [大约相等] 2000K）和临界温度・（t_ <cr> [大约等于] 1800K）之间的温度范围内维持灰​​尘，独立于T_ <eff>。然后，尘埃云出现在L Dwarfe的光学薄区域中，该区域的Teff相对较高，但会下降到Cooler T Dwarfe中可观察到的光球以下。观察到的CM图，SED和光谱与我们的UCM始终在整个L到T小矮人中始终如一。反过来，这一事实可以被视为我们云形成模型的观察性确认。我们希望我们的UCM将有一些线索来建模巨大巨型行星的气氛。较少的

项目成果

Tsuji, T.: "Water on the Early M Supergiant Stars α Orpomis and μ cephei"Astropys, J.. 538. L801-L807 (2000)

Tsuji, T.：“早期 M 超巨星 α Orpomis 和 μ cephei 上的水”Astropys, J.. 538. L801-L807 (2000)

Tsuji,T , ed. bu R. F. Wing: "Dust Formation in Stellar Photospheres : The Case of Carbon Stars from Dwarf to AGB , Proc. IAU Symp. The Carbon Star Phenomenon"Kluwer. 2000

辻，T，编辑。

T.Tsuji: "Dust formation in stellar photosphere"IAU Symp 177 Proceedings. 177. 313-324 (2000)

T.Tsuji：“恒星光球层中的尘埃形成”IAU Symp 177 会议记录。

T. Tsuji (T. Tsuji): "Warm dust in the cool brown dwarf Gliese22915 and spectroscopic diagnosis of dusty photospheres"Astrophysical Journal Letters. 520・2. L119-L122 (1999)

T. Tsuji（T. Tsuji）：“冷褐矮星 Gliese22915 中的温暖尘埃和尘埃光球层的光谱诊断”《天体物理学杂志快报》520・2（1999 年）。

Tsuji, T.: "Warm Dust in the Cool Brown Dwarfs Gltese 229 B and Spectoscopic Diagnosis of Dusty Photospheve"Astrophys.J.Letters. 520. L119-L122 (1999)

Tsuji, T.：“冷褐矮星 Gltese 229 B 中的温暖尘埃和尘埃光飞星的光谱诊断”Astrophys.J.Letters。