利用白矮星Gaia XP光谱搜寻大质量残骸行星系统宿主
Searching for Massive Remnant Planetary System Hosts with White Dwarf Gaia XP Spectra
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中文总结 AI 辅助
利用Gaia XP光谱高效识别大质量金属污染白矮星，扩大残骸行星系统宿主样本，并发现新凌星碎片系统SDSS J1624+5404。
中文摘要 AI 辅助
大质量白矮星（$M_{\rm WD} > 0.8\\,{\rm M}_\odot$）周围的残骸行星系统本质上非常罕见，且目前对其特征了解甚少。作为中等质量B型和A型恒星的演化终点，这些白矮星为研究较高质量前身星周围行星系统的形成与存续提供了宝贵的约束条件。在缺乏大规模专项光谱巡天的情况下，极低分辨率的Gaia XP光谱为识别候选金属污染白矮星提供了有力手段。我们利用低分辨率光学光谱（R=500-4000）进行了后续观测，主要针对从Gaia XP光谱中选出的、有效温度低于约$15{,}000$ K的大质量金属污染白矮星候选体搜寻Ca II H & K吸收线，以增加大质量残骸行星系统宿主的样本量。我们发现Gaia XP光谱能高效识别金属污染白矮星，在样本中高置信度候选体（分类器概率$P_{\rm DZ} > 0.65$）中确认了82$\pm$5%的光球金属恢复率（72个目标中的59个）。然而，由$G$、$G_{BP}$和$G_{RP}$宽带测光推导出的Gaia光度质量不足以识别质量最大的系统，因为可靠的质量测定需要详细的金属富集大气拟合。我们展示了一批经确认既大质量又金属污染的冷白矮星，证明Gaia XP光谱能大幅扩展白矮星系外行星宿主的样本。我们的搜索还发现了一个新的凌星碎片系统SDSS J1624+5404，这是迄今公布的第21个此类系统，也是第8个显示周期性凌星的系统。
英文摘要
Remnant planetary systems around massive white dwarfs ($M_{\rm WD} > 0.8\,{\rm M}_\odot$) are intrinsically rare and remain poorly characterized. As the evolutionary endpoints of intermediate-mass B- and A-type stars, these white dwarfs provide valuable constraints on the formation and survival of planetary systems around higher-mass progenitors. In the absence of large, dedicated spectroscopic surveys, extremely-low-resolution Gaia XP spectra provide a powerful means of identifying candidate metal-polluted white dwarfs. We obtained follow-up observations with low-resolution optical spectroscopy (R=500-4000) to search primarily for Ca II H & K absorption in massive, metal-polluted white dwarf candidates selected from Gaia XP spectra to increase the sample of massive remnant planetary system hosts among objects with effective temperatures below $\sim15{,}000$ K. We find that Gaia XP spectra recover metal-polluted white dwarfs efficiently, confirming 82$\pm$5% recovery of photospheric metals (59 of 72 targets) in high-confidence candidates of our sample (with classifier probability $P_{\rm DZ} > 0.65$). However, Gaia photometric masses derived from $G$, $G_{BP}$, and $G_{RP}$ broad-band photometry are not sufficient to identify the most massive systems, as reliable mass determinations require detailed metal-enriched atmospheric fits. We present a selection of cool white dwarfs confirmed to be both massive and metal polluted, demonstrating that Gaia XP spectra can substantially expand the sample of white dwarf exoplanet hosts. Our search led to the discovery of a new transiting debris system, SDSS J1624+5404, the 21st published system to date and eighth to show periodic transits.
发表机构
- Boston University（波士顿大学）
- Université de Montréal（蒙特利尔大学）
- University of Victoria（维多利亚大学）
- Center for Astrophysics — Harvard & Smithsonian（哈佛-史密森天体物理中心）
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