论文标题
WOCS 5379：质量转移蓝色Straggler的演变的详细分析
WOCS 5379: Detailed Analysis of the Evolution of a Post-Mass-Transfer Blue Straggler
论文作者
论文摘要
蓝色straggler二进制WOCS 5379是旧（6-7 Gyr）开放式群集NGC 188的成员。WOCS5379在120天的偏心轨道中包含带有白色矮人伴侣的蓝色Straggler Star。与轨道时期相结合，该氦白色矮人是红色巨人先前传质的证据。使用恒星天体物理学（MESA）实验的模块制作系统从祖细胞主序列二进制（包括传质）进化的系统演化的详细模型。两个祖细胞恒星都在模拟中演变。 WOCS 5379用初始质量1.19 $ m _ {\ odot} $的主要恒星很好地复制，其核心变成了白矮人。最初，次级恒星为1.01 $ m _ {\ odot} $。 300 Myr以前，次级完成了捐助者的质量，超越了NGC 188的转弯，为1.20 $ M _ {\ odot} $ blue Straggler。成功模型的传质效率为22 \％。这种非保守的传质是足够快地扩展轨道以允许稳定传质的关键。即便如此，质量转移始于短期不稳定的阶段，在此期间转移了一半的积聚质量。随着质量的增加，次级从辐射芯演变为对流芯。最终的蓝色Straggler内饰与2.1 Gyr-Old 1.21 $ M _ {\ odot} $ main-sequence Star处于HR图中的同一位置。还复制了白色矮人的有效温度，但是建模的白色矮人质量为0.33 $ m _ {\ odot} $小于0.42 $ m _ {\ odot} $的测量质量。
The blue-straggler binary WOCS 5379 is a member of the old (6-7 Gyr) open cluster NGC 188. WOCS 5379 comprises a blue straggler star with a white dwarf companion in a 120-day eccentric orbit. Combined with the orbital period, this helium white dwarf is evidence of previous mass transfer by a red giant. Detailed models of the system evolution from a progenitor main-sequence binary, including mass transfer, are made using the Modules for Experiments in Stellar Astrophysics (MESA). Both of the progenitor stars are evolved in the simulation. WOCS 5379 is well reproduced with a primary star of initial mass 1.19 $M_{\odot}$, whose core becomes the white dwarf. The secondary star initially is 1.01 $M_{\odot}$. 300 Myr ago, the secondary finished receiving mass from the donor, having moved beyond the NGC 188 turnoff as a 1.20 $M_{\odot}$ blue straggler. The successful model has a mass transfer efficiency of 22\%. This non-conservative mass transfer is key to expanding the orbit fast enough to permit stable mass transfer. Even so, the mass transfer begins with a short unstable phase, during which half of the accreted mass is transferred. With increasing mass, the secondary evolves from a radiative core to a convective core. The final blue straggler interior is remarkably similar to a 2.1 Gyr-old 1.21 $M_{\odot}$ main-sequence star at the same location in the HR diagram. The white dwarf effective temperature is also reproduced, but the modeled white dwarf mass of 0.33 $M_{\odot}$ is smaller than the measured mass of 0.42 $M_{\odot}$.
