Long-period variables in the Large Magellanic Cloud. II. Infrared photometry, spectral classification, AGB evolution, and spatial distribution
Long-period variables in the Large Magellanic Cloud. II. Infrared photometry, spectral classification, AGB evolution, and spatial distribution
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DOI：
10.1086/115374
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发表时间：
1990-03
期刊：
影响因子：
--
通讯作者：
S. Hughes;P. Wood
中科院分区：
文献类型：
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作者：
S. Hughes;P. Wood
对大麦哲伦星云（LMC）中大量长周期变元（lpv）进行了红外JHK光度测定和可见光光谱分析。利用这些数据讨论了lpv的渐近巨支（AGB）演化的各个方面。将LMC中不同年龄的lpv的出生/死亡率与行星状星云、星团、造父变星和OH/IR星的适当样本的出生/死亡率进行了比较。看来LMC中每单位星系恒星质量的大振幅lpv要比银河系少得多。这可能是由于LMC中演化的中年AGB恒星经常变成碳星，而碳星的脉动幅度往往小于M星。在LMC（和银河系）中lpv的数量与AGB演化、脉动和质量损失理论预测的数量之间也存在很大的差异。通过比较（K, log P）平面上的47个Tucanae Mira变量与LMC的距离模量，得出LMC的距离模量为18.66±0.05。参64。
Infrared JHK photometry and visual spectra have been obtained for a large sample of long-period variables (LPVs) in the Large Magellanic Cloud (LMC). Various aspects of the asymptotic giant branch (AGB) evolution of LPVs are discussed using these data. The birth/death rate of LPVs of different ages in the LMC is compared with the birth rates of appropriate samples of planetary nebulas, clump stars, Cepheids, and OH/IR stars. It appears that there are much fewer large-amplitude LPVs per unit galactic stellar mass in the LMC than in the Galaxy. It is suggested that this may be due to the fact that the evolved intermediate-age AGB stars in the LMC often turn into carbon stars, which tend to have smaller pulsation amplitudes than M stars. There is also a major discrepancy between the number of LPVs in the LMC (and in the Galaxy) and the number predicted by the theories of AGB evolution, pulsation, and mass loss. A distance modulus to the LMC of 18.66 + or - 0.05 is derived by comparing the LMC LPVs with P about 200 days with the 47 Tucanae Mira variables in the (K, log P) plane. 64 refs.