首页> 外文期刊>The Astrophysical journal >THE CLUSTER AGES EXPERIMENT (CASE). VII. ANALYSIS OF TWO ECLIPSING BINARIES IN THE GLOBULAR CLUSTER NGC 6362*
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THE CLUSTER AGES EXPERIMENT (CASE). VII. ANALYSIS OF TWO ECLIPSING BINARIES IN THE GLOBULAR CLUSTER NGC 6362*

机译:集群年龄实验(案例)。七。球形簇NGC 6362中的两个零星二值分析

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We use photometric and spectroscopic observations of the detached eclipsing binaries V40 and V41 in the globular cluster NGC 6362 to derive masses, radii, and luminosities of the component stars. The orbital periods of these systems are 5.30 and 17.89 days, respectively. The measured masses of the primary and secondary components (Mp, Ms) are (0.8337 ± 0.0063, 0.7947 ± 0.0048) M⊙ for V40 and (0.8215 ± 0.0058, 0.7280 ± 0.0047) M⊙ for V41. The measured radii (Rp, Rs) are (1.3253 ± 0.0075, 0.997 ± 0.013) R⊙ for V40 and (1.0739 ± 0.0048, 0.7307 ± 0.0046) R⊙ for V41. Based on the derived luminosities, we find that the distance modulus of the cluster is 14.74 ± 0.04 mag—in good agreement with 14.72 mag obtained from color–magnitude diagram (CMD) fitting. We compare the absolute parameters of component stars with theoretical isochrones in mass–radius and mass–luminosity diagrams. For assumed abundances [Fe/H] = ?1.07, [α/Fe] = 0.4, and Y = 0.25 we find the most probable age of V40 to be 11.7 ± 0.2 Gyr, compatible with the age of the cluster derived from CMD fitting (12.5 ± 0.5 Gyr). V41 seems to be markedly younger than V40. If independently confirmed, this result will suggest that V41 belongs to the younger of the two stellar populations recently discovered in NGC 6362. The orbits of both systems are eccentric. Given the orbital period and age of V40, its orbit should have been tidally circularized some ~7 Gyr ago. The observed eccentricity is most likely the result of a relatively recent close stellar encounter.
机译:我们使用球状星团NGC 6362中独立的食偏星V40和V41的光度学和光谱学观察来推导组成恒星的质量,半径和光度。这些系统的轨道周期分别为5.30天和17.89天。对于V40,主要和次要成分的质量测量值(Mp,Ms)为(0.8337±0.0063,0​​.7947±0.0048)M⊙,对于V41为(0.8215±0.0058,0.7280±0.0047)M⊙。对于V40,测得的半径(Rp,Rs)为(1.3253±0.0075,0.997±0.013)R⊙,对于V41为(1.0739±0.0048,0.7307±0.0046)R)。根据推导的光度,我们发现星团的距离模量为14.74±0.04 mag,这与从色幅图(CMD)拟合获得的14.72 mag非常吻合。我们在质量半径图和质量光度图中将组成恒星的绝对参数与理论等时线进行了比较。对于假定的丰度[Fe / H] = 1.07,[α/ Fe] = 0.4和Y = 0.25,我们发现V40的最可能年龄为11.7±0.2吉尔,与CMD拟合得出的簇的年龄兼容(12.5±0.5 Gyr)。 V41似乎比V40还要年轻。如果独立确认,该结果将表明V41属于NGC 6362中最近发现的两个恒星种群中的年轻者。两个系统的轨道都是偏心的。考虑到V40的轨道周期和年龄,它的轨道应该在约7个Gyr之前经过潮汐圆形化。观测到的离心率很可能是相对较近的恒星相遇的结果。

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