As the descendants of stars with masses less than 8 M⊙ on the main sequence, white dwarfs provide a unique way to constrain planetary occurrence around intermediate-mass stars (spectral types BAF) that are otherwise difficult to measure with radial-velocity or transit surveys. We update the analysis of more than 250 ultraviolet spectra of hot (13,000 K < Teff < 30,000 K), young (less than 800 Myr) white dwarfs collected by the Hubble Space Telescope, which reveals that more than 40% of all white dwarfs show photospheric silicon and sometimes carbon, signposts for the presence of remnant planetary systems. However, the fraction of white dwarfs with metals significantly decreases for massive white dwarfs (MWD > 0.8 M⊙), descendants of stars with masses greater than 3.5 M⊙ on the main sequence, as just % exhibit metal pollution. In contrast, 44% ± 6% of a subset of white dwarfs (MWD < 0.7 M⊙) unbiased by the effects of radiative levitation are actively accreting planetary debris. While the population of massive white dwarfs is expected to be influenced by the outcome of binary evolution, we do not find merger remnants to broadly affect our sample. We connect our measured occurrence rates of metal pollution on massive white dwarfs to empirical constraints of planetary formation and survival around stars with masses greater than 3.5 M⊙ on the main sequence.

中文翻译：

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对残余行星系统的约束与 HST/COS 的主序质量的函数关系


作为主序上质量小于 8 M⊙ 的恒星的后代，白矮星提供了一种独特的方法来限制中等质量恒星（光谱类型 BAF）周围的行星出现，否则这些恒星很难用径向速度或凌日巡天来测量。我们更新了哈勃太空望远镜收集的 250 多张热白矮星（13,000 K < Teff < 30,000 K）、年轻（小于 800 Myr）白矮星的紫外线光谱分析，结果显示超过 40% 的白矮星显示出光球层硅，有时还显示出碳，这是残余行星系统存在的标志。然而，对于大质量白矮星（MWD > 0.8 M⊙），大质量白矮星的金属比例显著降低，这是主序上质量大于3.5 M⊙的恒星的后代，因为只有%表现出金属污染。相比之下，不受辐射悬浮效应影响的白矮星子集（MWD < 0.7 M⊙）的 44% ± 6% 正在积极吸积行星碎片。虽然预计大质量白矮星的数量会受到双星演化结果的影响，但我们没有发现合并残余物会广泛影响我们的样本。我们将测得的大质量白矮星上金属污染的发生率与主序上质量大于 3.5 M⊙ 的恒星周围行星形成和生存的经验限制联系起来。