发表机构
Univ. Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，天体物理学与行星学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过N体模拟揭示双星潮汐收缩使稳定边界后退，过滤近边界环双星行星并增大其轨道偏移，从而解释观测到的非边际构型与环双星沙漠现象。
AI 中文摘要
环双星行星（CBPs）预期在环双星盘中形成，并朝着盘内腔迁移，通常靠近双星稳定边界。然而，观测到的种群并非严格处于边际稳定状态：排除极端系统后，典型偏移为 $\Delta \equiv a_{\rm p}/a_{\rm crit}=1.22^{+0.18}_{-0.07}$，这表明形成后的演化可能塑造了现今的构型。我们测试紧密双星的长期演化是否有助于这种位移。利用高精度 $N$ 体模拟，我们追踪初始位于 $a_{\rm crit}$ 附近的共面环双星行星，同时规定双星收缩和偏心率阻尼沿着近似守恒轨道角动量的轨迹进行。我们量化 $a_{\rm crit}(t)$ 的后退如何影响行星偏移和不同双星质量比下的存活率。移动的稳定边界过滤了近边界种群，增加了由收缩驱动的损失成分，其中以抛射为主。幸存者保持准化石状态，$a_{\rm p}$ 和 $e_{\rm p}$ 的中位数变化接近零，半长轴漂移仅为几个百分点。对于所有有效的合成幸存者，最终偏移的中位数为 $\Delta_f=1.86^{+0.18}_{-0.26}$。将相同的阻尼方案应用于观测样本，将中位数从 $\Delta_{\rm now}=1.22^{+0.18}_{-0.07}$ 移至 $\Delta_{\rm damp}=1.44^{+0.32}_{-0.10}$。近等质量双星经历更强的过滤，抛射和碰撞增强。因此，双星潮汐演化可以塑造非边际的环双星构型。通过移除接近边际稳定性的行星，同时使幸存者几乎保持化石状态，$a_{\rm crit}$ 的后退可以加宽内间隙并增加与现今稳定边界的偏移。这在一个多通道解释环双星沙漠的框架中，将双星轨道演化、动力学过滤和凌星可探测性联系起来。
英文摘要
Circumbinary planets (CBPs) are expected to form in circumbinary discs and migrate towards the disc inner cavity, often near the binary stability boundary. Yet the observed population is not strictly marginally stable: excluding extreme systems, the typical offset is $Δ\equiv a_{\rm p}/a_{\rm crit}=1.22^{+0.18}_{-0.07}$, suggesting post-formation evolution may shape present-day architectures. We test whether secular evolution of close binaries can contribute to this displacement. Using high-accuracy $N$-body simulations, we follow coplanar CBPs initially placed near $a_{\rm crit}$ while prescribing binary contraction and eccentricity damping along a track that approximately conserves orbital angular momentum. We quantify how the retreat of $a_{\rm crit}(t)$ affects planetary offsets and survival across binary mass ratios. The moving stability boundary filters the near-boundary population, adding a contraction-driven loss component dominated by ejections. Survivors remain quasi-fossilised, with median changes in $a_{\rm p}$ and $e_{\rm p}$ close to zero and semimajor-axis drifts of only a few per cent. For all valid synthetic survivors, the final offset has median $Δ_f=1.86^{+0.18}{-0.26}$. Applying the same damping prescription to the observed sample shifts the median from $Δ{\rm now}=1.22^{+0.18}{-0.07}$ to $Δ{\rm damp}=1.44^{+0.32}_{-0.10}$. Near-equal-mass binaries undergo stronger filtering, with enhanced ejections and collisions. Binary tidal evolution can therefore shape non-marginal circumbinary architectures. By removing planets close to marginal stability while leaving survivors nearly fossilised, the retreat of $a_{\rm crit}$ can widen the inner gap and increase offsets from the present-day stability boundary. This links binary orbital evolution, dynamical filtering, and transit detectability in a multi-channel interpretation of the CBP desert.
CommentsAccepted for publication in A&A. Shortened abstract for arXiv submission
