The actinium abundance in the atmospheres of red supergiants PMMR23 and PMMR144 in the Small Magellanic Cloud and RM_1-667 in the Large Magellanic Cloud was estimated. The results of spectral observations with the ESO 3.6-m telescope with resolving power R = 30000 were used. Since actinium was not found in the atmospheres of PMMR23 and PMMR144, only the upper limits were set on its abundance: logN(Ac/H) <–15.1 and–15.0, respectively. The estimated abundance of actinium in the atmosphere of RM_1-667 varied with parameters of the atmospheric model from–14.1 to–13.3. The lines of ionized actinium λ 616.475 nm and λ 581.085 nm were used in this analysis.

中文翻译：

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麦哲伦星云中三个红色超巨星大气中的化学丰度

估计小麦哲伦星云中的红色超级巨人PMMR23和PMMR144以及大麦哲伦星云中的RM_1-667大气中的in含量。使用ESO 3.6米望远镜的光谱观测结果，分辨力R = 30000。由于在PMMR23和PMMR144的大气层中未发现act，因此仅对其丰度设置了上限：log N（Ac / H）分别<–15.1和–15.0。RM_1-667大气中act的估计丰度随大气模型参数的变化而从–14.1到–13.3。在此分析中，使用了离子化的in线λ616.475 nm和λ581.085 nm。