三星系统中的LISA双白矮星
LISA Double White Dwarfs in Triple Systems
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中文总结 AI 辅助
本研究利用MSE代码模拟三星系统中的双白矮星演化，发现Ge模型通过稳定质量转移使LISA双白矮星产量提高约60%，并揭示了三星通道对引力波源的贡献。
中文摘要 AI 辅助
激光干涉仪空间天线（LISA）频段内的双白矮星（DWDs）是银河系主要的引力波源，但许多紧密双白矮星的前身可能存在于层级三星系统中。三星演化可以改变LISA双白矮星的产生率和参数分布。利用多星演化（MSE）代码，我们研究了绝热质量损失模型（Ge模型）和用于三星公共包层（TCE）演化的SCATTER形式体系如何影响三星通道的LISA双白矮星形成。我们的主模型演化10^5个三星系统，并包含这两种要素。三个控制模型各含10^4个三星系统，分别将质量转移稳定性判据改为原始MSE多方模型、移除SCATTER、或采用低金属丰度（Z=0.001）。我们还用相同框架演化10^6个孤立双星作为双星通道参考。在多方模型下动力学不稳定的系统在Ge模型下可以进行稳定的洛希瓣质量转移。这种持续的质量转移改变了供体星包层，降低了其束缚能，并帮助随后的公共包层阶段形成紧密双白矮星而非并合。相对于多方模型，Ge模型将三星通道的LISA双白矮星产量提高了约60%，而SCATTER对总产量的影响仅为约3%。经过停留时间加权后，三星系统贡献约1.3e7个LISA频段双白矮星，其中包括1.4e4个可单独分辨的系统。在三星加双星联合归一化中，双星通道贡献3.1e6个LISA频段双白矮星和4.7e3个可分辨系统；这些是联合种群中双星的份额，而非仅双星的银河系估计。主三星模型的质量比分布比多方模型三星更平坦且更高q，以He-CO和He-He双星为主，并且只有在伴星保持束缚时才产生罕见的偏心系统。
英文摘要
Double white dwarfs (DWDs) in the Laser Interferometer Space Antenna (LISA) band are major Galactic gravitational-wave sources, but many tight DWD progenitors may reside in hierarchical triples. Triple evolution can alter both the production rate and parameter distributions of LISA DWDs. Using the Multiple Star Evolution (MSE) code, we study how the adiabatic mass-loss model (Ge model) and the SCATTER formalism for triple common-envelope (TCE) evolution affect triple-channel LISA DWD formation. Our main model evolves 10^5 triples with both ingredients. Three control models, each with 10^4 triples, vary the mass-transfer stability criterion to the original MSE polytropic model, remove SCATTER, or adopt low metallicity (Z=0.001). We also evolve 10^6 isolated binaries with the same framework as a binary-channel reference. Systems that are dynamically unstable under the polytropic model can instead undergo stable Roche-lobe overflow under the Ge model. This sustained mass transfer modifies the donor envelope, reduces its binding energy, and helps the subsequent common-envelope phase form a close DWD rather than a merger. The Ge model increases the triple-channel LISA DWD yield by about 60% relative to the polytropic model, while SCATTER changes the integrated yield by only about 3%. After residence-time weighting, triples contribute about 1.3e7 LISA-band DWDs, including 1.4e4 individually resolvable systems. In the combined triple-plus-binary normalization, the binary channel contributes 3.1e6 LISA-band DWDs and 4.7e3 resolvable systems; these are the binary share of the combined population, not the binary-only Galactic estimate. The main triple model has a flatter, higher-q mass-ratio distribution than the polytropic-model triples, is dominated by He-CO and He-He binaries, and produces rare eccentric systems only when a tertiary star remains bound.
发表机构
- School of Physical Science and Technology, Xinjiang University（新疆大学物理科学与技术学院）
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