论文标题
GHz 20-25 \进化的恒星的光谱：在渐近巨型分支向行星星云转变期间追踪异理化学
The spectra of evolved stars at 20--25\,GHz: tracing circumstellar chemistry during the asymptotic giant branch to planetary nebula transition
论文作者
论文摘要
我们报告了在20至25 GHz的频率范围内对恒星的偶色信封的无偏无线电线调查，旨在在恒星演化的最后阶段获得更完整的化学演化图像。观察样本包括渐近巨型分支（AGB）星IRC+10216，原始星云星云（PPNS）CRL \，2688和CRL \，618，以及年轻的行星星云（PN）NGC \，NGC \，7027，代表了大约10,000年的进化序列。在AGB恒星和PPN中检测到从氰基链和氨的反转线的旋转过渡，而PN显示了几个重组线。这些进化的恒星的不同光谱行为清楚地反映了AGB-PPN-PN跃迁期间偶尔化学的演变。
We report an unbiased radio line survey towards the circumstellar envelopes of evolved stars at the frequency range from 20 to 25 GHz, aiming to obtain a more complete unbiased picture of the chemical evolution in the final stages of stellar evolution. The observation sample includes the asymptotic giant branch (AGB) star IRC+10216, the proto-planetary nebulae (PPNs) CRL\,2688 and CRL\,618, and the young planetary nebula (PN) NGC\,7027, representing an evolutionary sequence spanning about 10,000 years. Rotational transitions from cyanopolyyne chains and inversion lines from ammonia are detected in the AGB star and PPNs, while the PN displays several recombination lines. The different spectral behaviors of these evolved stars clearly reflect the evolution of circumstellar chemistry during the AGB-PPN-PN transitions.
