AI 中文总结
该研究利用JWST观测全质量范围5个年轻原恒星的H₂风，发现其形态运动学特性符合磁流体动力学盘风模型，且准直分子喷流与吸积率关联更紧密。
AI 中文摘要
分子风可能在原恒星早期演化过程中对角动量传输和吸积起到关键作用。我们利用詹姆斯·韦布空间望远镜（JWST）搭载的近红外光谱仪积分场单元（NIRSpec/IFU）和中红外仪器光谱仪（MIRI/MRS），作为研究原恒星吸积（IPA）项目的一部分，观测了5个处于宽热光度范围（0.2至10^4 L☉）、以星周包层为主的年轻原恒星，呈现了其中H₂发射的形态与运动学特性。在这些风中探测到了丰富的H₂纯转动线，直至v=0-0 S(18)，以及若干振转线，揭示出双极结构。H₂线在形态和运动学上呈现分层/洋葱状结构，其中具有更高上能级能量（E_up）的线表现出更高的准直度和更高的速度。此外，风速与宿主原恒星系统的热光度（L_bol）成比例。在5个原恒星中的4个里，H₂发射充满外流腔，未呈现明显的 limb brightening（ limb增亮）。我们还报告了在IRAS 16253中探测到的H₂风旋转的初步结果，这表明其发射半径约为4天文单位（au），磁杠杆臂参数约为5-10。总体而言，这些H₂风的特性可由磁流体动力学盘风模型解释。我们在HOPS 370中探测到了一束准直的高速H₂喷流，HOPS 370比极年轻天体HH 211演化程度更高，但吸积率很高，这表明原恒星中准直分子喷流的存在与吸积率的关联比与系统年龄的关联更为紧密。
英文摘要
Molecular winds may play a key role in governing angular momentum transport and accretion during the early evolution of protostars. We present the morphology and kinematic properties of the H$_2$ emission in five young, envelope-dominated, protostars across a broad bolometric luminosity range, from 0.2 to $10^4~L_{\odot}$, observed with the NIRSpec/IFU and MIRI/MRS onboard JWST as part of the Investigating Protostellar Accretion (IPA) program. A rich set of pure rotational lines of H$_2$, up to $v=0-0$ S(18), and a few ro-vibrational lines are detected in the winds, revealing bipolar structures. The H$_2$ lines show a stratified/onion-like structure morphologically and kinematically, where the lines with higher $E_{\rm up}$ show a higher degree of collimation and higher velocities. Additionally, the wind velocity scales with the $L_{\rm bol}$ of the host protostellar system. In 4 out of 5 protostars, H$_2$ emission fills the outflow cavity without showing pronounced limb brightening. We also report a tentative detection of H$_2$ wind rotation in IRAS 16253, which suggests a launch radius of $\sim4$ au and the magnetic lever arm parameter of $\sim5-10$. Taken together, these properties of the H$_2$ winds can be explained by the magnetohydrodynamic disk wind models. We detect a collimated, high-velocity H$_2$ jet toward HOPS 370, which is more evolved than the extremely young source HH 211, but is accreting at a high accretion rate. This suggests that the presence of collimated molecular jets in protostars is more closely connected to accretion rate than system age.
CommentsAccepted for publication in ApJ. 27 main text pages, 16 figures
