浮力晶体阻止白矮星冷却
Buoyant crystals halt the cooling of white dwarf stars
AI总结：
本研究提出白矮星核心冻结时的固—液蒸馏与浮力晶体上升机制，可释放引力能并使冷却停滞数十亿年，从而解释异常恒定光度星群。
摘要：
白矮星是没有核能源的恒星遗迹，会在数十亿年间逐渐冷却，并最终由内向外冻结为固态。最近发现，一批正在冻结的白矮星在与宇宙年龄相当的时间内保持恒定光度，这表明存在一种强大但未知的抑制冷却的能源。对于某些核心成分，由于固相中重杂质贫化，据预测冻结过程会触发固—液蒸馏机制。由此形成的晶体具有浮力并向上浮起，从而将较重的液体向下排开并释放引力能。我们在此表明，蒸馏会使冷却中断数十亿年，并解释这一异常延迟星群的所有观测性质。这些白矮星的稳定光度超过了一些主序星，挑战了它们作为死亡恒星的传统形象。我们的结果突显了特殊并合遗迹的存在，并对白矮星用于测定恒星种群年龄具有深远意义。
英文摘要：
White dwarfs are stellar remnants devoid of a nuclear energy source, gradually cooling over billions of years and eventually freezing into a solid state from the inside out. Recently, it was discovered that a population of freezing white dwarfs maintains a constant luminosity for a duration comparable to the age of the universe, signaling the presence of a powerful yet unknown energy source that inhibits the cooling. For certain core compositions, the freezing process is predicted to trigger a solid-liquid distillation mechanism, due to the solid phase being depleted in heavy impurities. The crystals thus formed are buoyant and float up, thereby displacing heavier liquid downward and releasing gravitational energy. Here we show that distillation interrupts the cooling for billions of years and explains all the observational properties of the unusual delayed population. With a steady luminosity surpassing that of some main-sequence stars, these white dwarfs defy their conventional portrayal as dead stars. Our results highlight the existence of peculiar merger remnants and have profound implications for the use of white dwarfs in dating stellar populations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
