GW Ori 三星系统三重盘结构中的流致对准偏差
A Streamer Driving Misalignment in the Circumtriple Disk of GW Ori
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中文总结 AI 辅助
研究发现 GW Ori 三星系统的流致最外侧尘埃环对准偏差约 3°，可能是其盘结构错位的驱动因素，该流或源于邦迪-霍伊尔吸积，GW Ori 仍与诞生星云保持动力学联系。
中文摘要 AI 辅助
GW Orionis 是一个拥有三个错位尘埃环的三星系统，我们展示了 ALMA（阿塔卡马大型毫米/亚毫米波阵列）的 CO 同位素分子线数据，揭示了一条在 $^{12}$CO 和 $^{13}$CO 中为该盘提供物质的流。通过多点观测，我们发现该流在天球上延伸至约 30''（约 12000 AU），并利用 $^{13}$CO 估算其质量为 1.6 M$_{\rm Jup}$。通过拟合流的形态和运动学，我们估算其质量吸积时标为 0.04 Myrs，质量吸积率为 $3.6\times10^{-8}$ M$_{\rm \odot}$ yr$^{-1}$，约比恒星吸积率低一个数量级。我们的最佳拟合轨迹显示，该流与最外侧尘埃环相遇，且流的角动量矢量与最外侧环的对准偏差约为 $3^\circ$，而与最内侧环的对准偏差约为 $32^\circ$，表明该流可能是导致错位的原因。然而，该流的总角动量小于 GW Ori 盘的角动量；结合其低吸积率，表明我们可能观测到的是吸积的最后阶段。总功率观测揭示了连接该流与周围恒星形成区的明亮发射，其投影距离完全落在邦迪-霍伊尔半径内，意味着该流可能是 GW Ori 穿过其诞生星云时通过邦迪-霍伊尔吸积形成的。综合这些结果表明，GW Ori 通过持续吸积仍与其诞生星云保持动力学联系，该流是其错位盘结构的可能驱动因素。
英文摘要
GW Orionis is a triple stellar system with a disk featuring three misaligned dust rings. We present ALMA molecular line data of CO isotopologues, revealing a streamer feeding the disk in $^{12}$CO and $^{13}$CO. Through multi-pointing observations, we find the streamer extends to $\sim30''$ on-sky ($\sim12,000$~AU) and estimate a mass of 1.6 M$_{\rm Jup}$ using $^{13}$CO. Fitting the morphology and kinematics of the streamer, we estimate the mass infall timescale of 0.04 Myrs and a mass infall rate of $3.6\times10^{-8}$~M$_{\odot}$~yr$^{-1}$, approximately an order of magnitude lower than the stellar accretion rate. Our best-fit trajectory shows that the streamer meets the disk at the outermost dust ring and that the streamer's angular momentum vector is closely aligned with this outermost ring within $\approx3^\circ$, in contrast to the $\approx32^\circ$ misalignment with the innermost ring, suggesting the streamer is the likely cause of the misalignment. However, the total angular momentum of the streamer is smaller than that of GW Ori's disk; this, together with the low accretion rate, indicates that we are probably witnessing the end stages of infall. Total Power observations reveal bright emission connecting the streamer to the surrounding star-forming region, with a projected distance falling well within the Bondi-Hoyle radius, implying the streamer could have originated through Bondi-Hoyle accretion as GW Ori moves through its natal cloud. Together, these results suggest that GW Ori remains dynamically linked to its parental cloud through ongoing accretion, with the streamer serving as the likely driver of its misaligned disk structure.
