发现第二世代行星候选体吸积到白矮星上
Discovery of a second-generation planet candidate accreting onto a white dwarf
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中文总结 AI 辅助
发现白矮星HS 0209+0832吸积富含s过程元素、缺乏造岩元素的物质，表明其吸积对象为第二世代行星候选体，可能源自光蒸发巨行星的逃逸大气，并通过光度周期变化得到支持。
中文摘要 AI 辅助
许多白矮星吸积被瓦解的行星体碎片，这些碎片通过其大气中的金属富集、尘埃或气体环星盘以及碎屑的光度凌星信号被探测到。已证明吸积碎片的成分多样，但总体上与太阳系天体非常相似。我们报告发现一颗白矮星吸积的物质不同于任何太阳系天体。HS 0209+0832的大气强烈富集跨铁元素，包括锌、铜和铌，但缺乏标准的造岩元素硅和铁。吸积天体的成分与第二世代行星候选体一致，该行星由巨星阶段抛出的恒星物质形成。将其与第一世代行星区分开来的关键丰度特征是s过程元素的高度富集。光球层中的氦以及缺乏地球造岩元素表明，该白矮星正在吸积一颗光蒸发巨行星候选体逃逸大气中的物质。这一结论进一步得到正弦光度周期4.399±0.026天、振幅0.120±0.018%的探测支持，我们将其归因于行星昼夜循环的热辐射相位变化或蒸发气态巨行星的凌星彗尾。
英文摘要
Many white dwarfs accrete the debris of disrupted planetary bodies, detected in the form of metal-enrichment in their atmospheres, dusty or gaseous circumstellar discs, and photometric transits from debris. The composition of accreted debris has been shown to be diverse yet overall closely resembles Solar System bodies. We report the discovery of a white dwarf accreting material that is unlike any Solar System object. The atmosphere of HS 0209+0832 is strongly enriched in trans-iron elements including zinc, copper, and niobium but depleted in the canonical rock-forming elements silicon and iron. The composition of the accreted object is consistent with a candidate second-generation planet, formed from the stellar material ejected during the giant phase. The key abundance signature which differentiates it from a first-generation planet is the high enrichment of s-process elements. Photospheric helium and the absence of terrestrial rock-forming elements implies the white dwarf is accreting from the escaped atmosphere of a photo-evaporating giant planet candidate. This is further supported by the detection of a sinusoidal photometric period of 4.399+/-0.026 days at an amplitude of 0.120+/-0.018 %, which we attribute to thermal emission phase variability from a planetary day-night cycle or a transiting cometary tail of an evaporating gas giant.
发表机构
- Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）
- University of Warwick（华威大学）
- The Hebrew University（希伯来大学）
- University of Wisconsin, Madison（威斯康星大学麦迪逊分校）
- University of Kiel（基尔大学）
- MIT（麻省理工学院）
- University of Colorado, Boulder（科罗拉多大学博尔德分校）
- Center for Astrophysics | Harvard & Smithsonian（哈佛与史密森尼天体物理中心）
- Space Telescope Science Institute（太空望远镜科学研究所）
机构由 AI 辅助整理，请以论文原文为准。
