AI 中文总结
本研究通过 SCExAO/CHARIS 等观测验证了4颗罗曼日冕仪技术演示用 PSF 参考星的伴星情况，确认其无会干扰行星探测的亮伴星，还评估了目标可观测性并提出优化调度的参考星选择。
AI 中文摘要
我们针对罗曼空间望远镜（Roman）连续观测带内及附近的4颗候选罗曼日冕仪（Roman Coronagraph）点扩散函数（PSF）参考星，开展了深度的 SCExAO/CHARIS 高对比度积分场光谱观测，并结合存档成像数据，这些参考星潜在适用于日冕仪核心技术演示目标 HIP 71618 和 HIP 54515。对于 CHARIS 数据，我们在 0.16角秒、0.25角秒、0.5至1角秒处分别达到约1.4×10⁻⁵、约6×10⁻⁶、10⁻⁶至4×10⁻⁷的5σ对比度。伴星质量限制排除了所有目标在 ρ≈0.15至0.25角秒处的褐矮星，以及在更远分离处的大质量行星。更关键的是，对于4颗参考星中的3颗，我们的分析不支持在0.15角秒、0.3角秒、1角秒处V波段对比度亮于10⁻⁸、10⁻⁹、10⁻¹⁰的伴星存在。除非这些目标在ρ≈0.15角秒内存在暗淡的亚恒星伴星，否则它们可能不存在会破坏罗曼日冕仪暗区（dark hole）、阻碍反射光行星探测的背景星或伴星。对于 α Cep，其对比度限制比上述结果差约10倍，但在ρ≈0.25角秒外仍满足 TTR5 10⁻⁷的限制；在0.4角秒外，其限制排除了木星双胞胎反射光伴星（10⁻⁹）。存档的 Keck/NIRC2 数据同样在更远分离处未发现ΔV>10⁻⁸的亚恒星伴星。最后，我们评估了 HIP 71618 和 HIP 54515 的可观测性，更新了罗曼望远镜2026年8月30日的发射时间；加入目前未列入罗曼 CPP 团队参考星列表的 γ Boo，将提升技术演示核心目标的调度可行性。
英文摘要
We present deep, SCExAO/CHARIS high-contrast integral field spectroscopy and archival imaging of four candidate Roman Coronagraph PSF reference stars within/near the Roman Continuous Viewing Zone and potentially suitable for the Coronagraph's key technology demonstration targets HIP 71618 and HIP 54515. For CHARIS data, we achieve 5-$σ$ contrasts down to $\sim$1.4$\times$10$^{-5}$, $\sim$6$\times$10$^{-6}$, and 10$^{-6}$ to 4$\times$10$^{-7}$ at 0\farcs{}16, 0\farcs{}25, and 0\farcs{}5 to 1\arcsec{}. Companion mass limits rule out brown dwarfs at $ρ$ $\sim$ 0\farcs{}15--0\farcs{}25 and massive planets at wider separations around all targets. More critically, for three of the four references our analysis disfavors companions with $V$ band contrasts brighter than 10$^{-8}$, 10$^{-9}$, and $10^{-10}$ at 0\farcs{}15, 0\farcs{}3, and 1$\arcsec{}$. Unless these targets have faint substellar companions within $ρ$ $\sim$ 0\farcs{}15, they likely lack background stars or companions that could corrupt the Roman Coronagraph's dark hole digging to preclude detecting reflected-light planets. For $α$ Cep, our limits are a factor of $\sim$10 worse but still meet the TTR5 limit of 10$^{-7}$ beyond $ρ$ $\sim$ 0\farcs{}25: beyond 0\farcs{}4, they exclude a Jupiter-twin reflected-light companion (10$^{-9}$). Archival Keck/NIRC2 data likewise find no substellar companions with $Δ$V $>$ 10$^{-8}$ at wider separations. Finally, we assess the observability of HIP 71618 and HIP 54515 -- updated for Roman's launch date of August 30, 2026. Adding $γ$ Boo -- not currently in the Roman CPP team reference-star list -- would improve schedulability for the tech demo's key targets.
Comments12 pages, 6 figures, 3 tables; first extreme AO-depth vetting of Roman Coronagraph PSF reference stars
