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carbon star 【天文學】碳星。

carbon-copy

Because the photospheric temperature of carbon stars are less than 3000k and the temperature of rich - dust envelope formed by the mass loss is lower , and therefore most of the energy from carbon stars are radiated between 1 to 60um range , in which the vibrational and ro - vibrational bands of many molecules also lies , the study of infrared spectra in this wavelength range is very important to reveal chemical compositions , dust formation process , the atmospheric structure and evolutionary status of stars 碳星光球的有效溫度不超過3000k ,同時較大的質量損失率形成了富碳的塵埃殼層,以致于它的輻射能量主要集中在1 ? 60 m的紅外波段上,并且許多分子的轉動振動能譜也集中在紅外,因此在紅外波段的研究對揭示碳星化學成份及其分布、塵埃形成過程、恒星大氣結構和演化狀態都有十分重要的意義。

Visual carbon stars whose mid - infrared spectra are mainly dominated by photospheric continuum and show large excesses at 60um , represent a transition phase which follows an interruption of mass loss from the oxygen - rich phase and begins a new phase of the mass loss of carbon - rich material . excesses at 60um in these stars are the emission from the residual of oxygen - rich material 光學碳星的中紅外能量主要來自光球,在60 m處存在超量發射,人們認為其演化階段處在拋射富氧物質終止和新的富碳拱星殼層形成之間,其60 m超量發射就是富氧物質的殘余效應。

We have elected 29 carbon stars with sic emission feature at 11 . 3um , i . e . sic carbon stars , which include visual carbon stars , infrared carbon stars and extreme carbon stars to be our working samples in this paper 本文將選取29顆富碳agb星作為研究對象,它們均有11 . 3 msic發射特征,在本文中稱之為碳化硅碳星( sic碳星) ,它們覆蓋了光學碳星、紅外碳星和極端碳星的階段。

The infrared carbon stars , whose infrared spectra are mainly due to the dust emission in the circumstellar envelope , are usually believed to be surrounded by the carbon rich envelope characterized by the sic emission feature at 11 . 3um 紅外碳星常被認為有很厚的富碳拱星殼層,它的紅外光譜主要表現為源于拱星殼層的塵埃發射,這個塵埃發射主要以11 . 3 m的sic發射為標記。

The extreme carbon stars , whose derived mass loss rates and optical depths are both very high , are more evolved than infrared carbon stars . these stars are expected to evolve into protoplanatary nebula soon 極端碳星是高度演化后的紅外碳星,它的質量損失率及光深都非常高,幾乎沒有其光學對應體,并將很快演化為前行星狀星云。

By using the iso sws spectra we have studied their physical nature including their molecular and dust features in the circumstellar envelope to make us understand the evolutionary status of carbon stars 這29顆sic碳星的isosws光譜能很好地反映碳星的演化,有助于我們了解碳星的演化及其分子、塵埃特征。

After competing our work , some conclusions expected are obtained for the evolutionary principles of carbon stars and the evolutionary nature of molecule and dust features around them 在對它們的研究和分析后得到了我們所期待的關于碳星的一些演化規律和分子、塵埃特征的演化特性。

This present paper is contributed to the study of the evolutionary nature of iso sws spectra from carbon - rich agb stars ( carbon stars ) and molecular and dust features around such carbon stars 本文主要致力于研究富碳agb星的isosws紅外光譜的演化和它的分子、塵埃特征。

These stars are undergoing important mass loss process and are likely to represent a more evolved phase of the stellar evolution than visual carbon stars 紅外碳星經歷了重要的質量損失過程,是光學碳星演化的后期。

Carbon stars with c / o > 1 are a kind of stars that form at the agb stage and evolved from oxygen - rich agb stars with mid - mass 碳星是中等質量星演化到agb階段時可能形成的一種恒星,它由氧星演化而來, [ c o ] 1 。

Usually , carbon stars can be divided into three groups : visual carbon stars , infrared carbon stars and extreme carbon stars 通常,碳星又主要分為光學碳星、紅外碳星以及極端碳星。