Testing White Dwarf Age Estimates Using Wide Double White Dwarf Binaries from Gaia EDR3
Testing White Dwarf Age Estimates Using Wide Double White Dwarf Binaries from Gaia EDR3
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DOI：
10.3847/1538-4357/ac78d9
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
T. Heintz;J. Hermes;K. El-Badry;Charlie Walsh;J. V. van Saders;C. Fields;D. Koester
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作者：
T. Heintz;J. Hermes;K. El-Badry;Charlie Walsh;J. V. van Saders;C. Fields;D. Koester
白矮星的演化过程简单且可预测，这使它们成为可靠的年龄指标。然而，确定WD总年龄的方法的自我一致性验证尚未广泛进行。这项工作使用了1565个宽(>；100 Au)Wd+Wd双星和24个新的包含至少两个Wd的三元组来测试Wd总年龄测定的准确性和有效性。对于这1589个宽的双WD双星和三重WD，我们使用全天观测的光度数据，结合Gaia视差和当前的氢大气WD模型，得出了每个WD的总年龄。忽略初始到最终的质量关系，只考虑WD的冷却年龄，我们发现，在一个系统中，大约21%-36%的较大质量的WD具有较短的冷却年龄。由于更大质量的wd应该诞生为更大质量的主序恒星，我们将这种非物理的不一致解释为先前合并或存在未解决的伴星的证据，这表明大约21%-36%的wd+wd双星曾经是三倍的。在通过高保真切割的423对宽WD+WD中，我们发现25%的总年龄不确定性通常适用于具有质量&>0.63M⊙和温度<；12,000K的WD，并为较高质量WD的年龄不确定性提供了建议的通胀因素。总体而言，WDS返回了可靠的恒星年龄，但我们详细说明了总年龄最不可靠的情况，特别是WDS<；0.63M⊙。
White dwarf (WD) stars evolve simply and predictably, making them reliable age indicators. However, self-consistent validation of the methods for determining WD total ages has yet to be widely performed. This work uses 1565 wide (>100 au) WD+WD binaries and 24 new triples containing at least two WDs to test the accuracy and validity of WD total age determinations. For these 1589 wide double WD binaries and triples, we derive the total age of each WD using photometric data from all-sky surveys, in conjunction with Gaia parallaxes and current hydrogen atmosphere WD models. Ignoring the initial-to-final mass relation and considering only WD cooling ages, we find that roughly 21%–36% of the more massive WDs in a system have a shorter cooling age. Since more massive WDs should be born as more massive main-sequence stars, we interpret this unphysical disagreement as evidence of prior mergers or the presence of an unresolved companion, suggesting that roughly 21%–36% of wide WD+WD binaries were once triples. Among the 423 wide WD+WD pairs that pass high-fidelity cuts, we find that 25% total age uncertainties are generally appropriate for WDs with masses >0.63 M ⊙ and temperatures <12,000 K and provide suggested inflation factors for age uncertainties for higher-mass WDs. Overall, WDs return reliable stellar ages, but we detail cases where the total ages are least reliable, especially for WDs <0.63 M ⊙.