AI 中文总结
研究利用 JWST/MIRI 观测 IC348 中 T Tauri 盘，发现其虽有分子比率多样性，但内盘 C/O 比在盘质量下降时几乎无演化，与模型预测矛盾，且冷热水通量比无演化、与碳氢化合物与水比率无关，表明多数内盘不受卵石漂移主导，避免了相关问题。
AI 中文摘要
内盘化学为研究盘演化和行星形成提供了重要窗口。关键的行星形成过程，如卵石漂移、星子和行星形成、尘埃陷阱及雪线，决定了氧和碳向内盘的输送速率。因此，对不同年龄盘内对气相 C/O 比敏感分子的测量，可限制这些过程的相对重要性和时间演化。本文报告了对年轻星团 IC 348 中 T Tauri 盘的 JWST/MIRI 观测，扩展了以往对盘的研究年龄范围。IC 348 源与年轻盘一样，显示出广泛的分子比率，表明行星形成历史多样。然而，IC 348（2 - 5 Myr 龄）和金牛座（1 - 2 Myr 龄）源相似的 HCN/H₂O 和 C₂H₂/H₂O 通量比分布意味着在此时间间隔内，即使盘质量平均下降 5 倍，内盘 C/O 比几乎没有演化。这一结果与盘化学演化模型中 C/O 比随时间增加的一般预测相矛盾，表明需要更好地理解行星形成与盘演化过程之间的相互作用（及其效率）。我们还发现冷热水通量比没有演化，且与碳氢化合物与水的比率无关。这些结果表明，大多数内 T Tauri 盘不受快速冰质卵石漂移主导，避免了曾被认为是行星形成障碍的“米级屏障问题”。
英文摘要
Inner disk chemistry offers a valuable window onto disk evolution and planet formation. Key planet formation processes, including pebble drift, planetesimal and planet formation, dust traps, and snow lines, determine the delivery rates of oxygen and carbon to the inner disk. As a result, measurements of molecules sensitive to the gas-phase C/O ratio, in disks over a range of ages, can constrain the relative importance and time evolution of these processes. Here we report JWST/MIRI observations of T Tauri disks in the young cluster IC 348, extending to older ages previous studies of disks. Like younger disks, IC 348 sources show a broad range of molecular ratios, indicating diverse planet formation histories. However, the similar HCN/H$_2$O and C$_2$H$_2$/H$_2$O flux ratio distributions of IC 348 (2--5 Myr old) and Taurus (1--2 Myr old) sources imply little to no evolution in the inner disk C/O ratio over this time interval, even as disk masses decline by a factor of 5 on average. This result contradicts the general prediction of increasing C/O ratio with time in models of disk chemical evolution, indicating the need to better understand the interplay between (and efficiencies of) planet formation and disk evolution processes. We also find that the cold-to-warm water flux ratios show no evolution and do not correlate with the hydrocarbon-to-water ratios. These results suggest that most inner T Tauri disks are not dominated by rapid icy pebble drift and avoid the ''meter-size barrier problem'' once thought to be an obstacle to planet formation.
CommentsAccepted for publication in The Astrophysical Journal. 30 pages, 20 figures, 5 tables
