| 1. | Usually , carbon stars can be divided into three groups : visual carbon stars , infrared carbon stars and extreme carbon stars
通常，碳星又主要分为光学碳星、红外碳星以及极端碳星。 |
| 2. | 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
碳星是中等质量星演化到agb阶段时可能形成的一种恒星，它由氧星演化而来， [ c o ] 1 。 |
| 3. | 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
红外碳星经历了重要的质量损失过程，是光学碳星演化的后期。 |
| 4. | 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
在对它们的研究和分析后得到了我们所期待的关于碳星的一些演化规律和分子、尘埃特征的演化特性。 |
| 5. | 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
这29颗sic碳星的isosws光谱能很好地反映碳星的演化，有助于我们了解碳星的演化及其分子、尘埃特征。 |
| 6. | 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
极端碳星是高度演化后的红外碳星，它的质量损失率及光深都非常高，几乎没有其光学对应体，并将很快演化为前行星状星云。 |
| 7. | 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
红外碳星常被认为有很厚的富碳拱星壳层，它的红外光谱主要表现为源于拱星壳层的尘埃发射，这个尘埃发射主要以11 . 3 m的sic发射为标记。 |
| 8. | 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
本文将选取29颗富碳agb星作为研究对象，它们均有11 . 3 msic发射特征，在本文中称之为碳化硅碳星( sic碳星) ，它们覆盖了光学碳星、红外碳星和极端碳星的阶段。 |
| 9. | 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
光学碳星的中红外能量主要来自光球，在60 m处存在超量发射，人们认为其演化阶段处在抛射富氧物质终止和新的富碳拱星壳层形成之间，其60 m超量发射就是富氧物质的残余效应。 |
| 10. | 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
碳星光球的有效温度不超过3000k ，同时较大的质量损失率形成了富碳的尘埃壳层，以致于它的辐射能量主要集中在1 ? 60 m的红外波段上，并且许多分子的转动振动能谱也集中在红外，因此在红外波段的研究对揭示碳星化学成份及其分布、尘埃形成过程、恒星大气结构和演化状态都有十分重要的意义。 |
