WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548)
WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548)
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DOI：
10.3847/1538-3881/ab83ef
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
Qinghui Sun;C. Deliyannis;A. Steinhauer;B. Twarog;B. Anthony-Twarog
中科院分区：
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作者：
Qinghui Sun;C. Deliyannis;A. Steinhauer;B. Twarog;B. Anthony-Twarog
利用Li 6708 Å周围400 Å区域的WIYN/Hydra光谱（R ~ 13,500，信噪比像素−1 = 50-1000）来确定疏散星团M48中287个候选成员的径向和旋转速度。样本范围从关闭的A型恒星到晚期k型矮星和8颗巨星。我们将VRAD测量和功率谱分析与来自Gaia DR2的视差和固有运动数据相结合，以评估成员和多样性。我们将152颗恒星分类为单一星团成员，11颗为双星成员，16颗为不确定多重成员，56颗为单一非成员，28颗为单一“可能”非成员，2颗为单一“可能”成员，1颗为二元“可能”成员，5颗为二元非成员，10颗为不确定多重“可能”成员，3颗为不确定多重“可能”成员，3颗为不确定多重“可能”成员，3颗为不确定多重“可能”非成员。从95个单体子样本中，我们得到VRAD = 8.512±0.087 km s−1 （σμ, σ = 0.848 km s−1）。用16个分离的Fe - 1谱线对99个单体子样品（K（来自UBVRI的10种颜色），v sin I < 25 km s−1，表现良好的Fe - 1谱线），[Fe/H]M48 = - 0.063±0.007指数（σμ）。[Fe/H]在2500k的空前大范围内与Teff无关。最小星团二元分数为11%-21%。M48显示出明显但适度的主序关闭拓宽，并且颜色与v sin i之间没有相关性。
WIYN/Hydra spectra (R ∼ 13,500, signal-to-noise pixel−1 = 50–1000) of a 400 Å region around Li 6708 Å are used to determine radial and rotational velocities for 287 photometrically selected candidate members of the open cluster M48. The sample ranges from turnoff A stars to late-K dwarfs and eight giants. We combine our VRAD measurements and power spectrum analysis with parallax and proper motion data from Gaia DR2 to evaluate membership and multiplicity. We classify 152 stars as single cluster members, 11 as binary members, 16 as members of uncertain multiplicity, 56 as single nonmembers, 28 as single “likely” nonmembers, two as single “likely” members, one as a binary “likely” member, five as binary nonmembers, 10 as “likely” members of uncertain multiplicity, three as nonmembers of uncertain multiplicity, and three as “likely” nonmembers of uncertain multiplicity. From a subsample of 95 single members, we derive VRAD = 8.512 ± 0.087 km s−1 (σμ, and σ = 0.848 km s−1). Using 16 isolated Fe I lines for a subsample of 99 single members (that have K (from 10 colors from UBVRI), v sin i < 25 km s−1, and well-behaved Fe I lines), [Fe/H]M48 = −0.063 ± 0.007 dex (σμ). [Fe/H] is independent of Teff over an unprecedentedly large range of 2500 K. The minimum cluster binary fraction is 11%–21%. M48 exhibits a clear but modest broadening of the main-sequence turnoff, and there is no correlation between color and v sin i.