前恒星核Ophiuchus/H-MM1中的低宇宙射线电离率：分子离子ortho-H2D+、N2H+和DCO+的测绘

The initial conditions of isolated star formation - X. A suggested evolutionary diagram for prestellar cores

We propose an evolutionary path for prestellar cores on the radius-mass diagram, which is analogous to stellar evolutionary paths on the Hertzsprung-Russell Diagram. Using James Clerk Maxwell Telescope (JCMT) observations of L1688 in the Ophiuchus star-forming complex, we analyse the HCO+ (J=4\rightarrow3) spectral line profiles of prestellar cores. We find that of the 58 cores observed, 14 show signs of infall in the form of a blue-asymmetric double-peaked line profile. These 14 cores all lie beyond the Jeans mass line for the region on a radius-mass plot. Furthermore another 10 cores showing…

Ophiuchus分子云及其L1688轴-丝系统中的核与纤维性质

Properties of the cores and filaments in the Ophiuchus molecular cloud and its L1688 hub-filament system

本文利用getsf方法分析Ophiuchus分子云L1688轴-丝系统，构建核与纤维质量函数并评估形成效率，揭示了纤维主导的核形成是恒星形成的关键机制。

Efficient methanol production on the dark side of a prestellar core

We present ALMA maps of the starless molecular cloud core Ophiuchus/H-MM1 in the lines of deuterated ammonia (ortho-NH2D), methanol (CH3OH), and sulphur monoxide (SO). The dense core is seen in NH2D emission, whereas the CH3OH and SO distributions form a halo surrounding the core. Because methanol is formed on grain surfaces, its emission highlights regions where desorption from grains is particularly efficient. Methanol and sulphur monoxide are most abundant in a narrow zone that follows the eastern side of the core. This side is sheltered from the stronger external radiation field coming fro…

Simulating star formation in Ophiuchus

We have simulated star formation in prestellar cores, using SPH and initial conditions informed by observations of the cores in Ophiuchus. Because the observations are limited to two spatial dimensions plus radial velocity, we cannot infer initial conditions for the collapse of a particular core. However, with a minimum of assumptions (isotropic turbulence with a power-law spectrum, a thermal mix of compressive and solenoidal modes, a critical Bonnor-Ebert density profile) we can generate initial conditions that match, in a statistical sense, the distributions of mass, projected size and aspec…

JCMT BISTRO调查：通过相对取向直方图解释Ophiuchus分子云中恒星形成核心的磁化演化

The JCMT BISTRO Survey: The magnetised evolution of star-forming cores in the Ophiuchus Molecular Cloud interpreted using Histograms of Relative Orientation

通过分析Ophiuchus分子云中密集核心的B场方向，研究其磁化演化，发现高长轴比核心产生强HRO信号，而低长轴比核心则表现为ξ≈0，表明磁场与列密度梯度相关。

核前恒星核中氘代氨的核自旋比：LAsMA对H-MM1和Oph D的观测

Nuclear spin ratios of deuterated ammonia in prestellar cores. LAsMA observations of H-MM1 and Oph D

通过LAsMA观测两个核前恒星核，测定NH2D和NHD2的正/仲比接近统计值，气相质子交换情景决定自旋比，化学脱附影响丰度。

A (sub)millimetre study of dense cores in Orion B9

We aim to further constrain the properties and evolutionary stages of dense cores in Orion B9. The central part of Orion B9 was mapped at 350 micron with APEX/SABOCA. A sample of nine cores in the region were observed in C17O(2-1), H13CO+(4-3) (towards 3 sources), DCO+(4-3), N2H+(3-2), and N2D+(3-2) with APEX/SHFI. These data are used in conjunction with our previous APEX/LABOCA 870-micron dust continuum data. Many of the LABOCA cores show evidence of substructure in the higher-resolution SABOCA image. In particular, we report on the discovery of multiple very low-mass condensations in the pre…

Infall/Expansion Velocities in the Low-Mass Dense Cores L492, L694-2, and L1521F: Dependence on Position and Molecular Tracer

Although surveys of infall motions in dense cores have been carried out for years, few surveys have focused on mapping infall across cores using multiple spectral line observations. To fill this gap, we present IRAM 30-m Telescope maps of N2H+(1-0), DCO+(2-1), DCO+(3-2), and HCO+(3-2) emission towards two prestellar cores (L492 and L694-2) and one protostellar core (L1521F). We find that the measured infall velocity varies with position across each core and choice of molecular line, likely as a result of radial variations in core chemistry and dynamics. Line-of-sight infall speeds estimated fr…

APEX observations of ortho-H$_2$D$^+$ towards dense cores in the Orion B9 filament

We used the APEX telescope to observe the 372 GHz o-H$_2$D$^+(J_{K_a,\,K_c}=1_{1,\,0}-1_{1,\,1})$ line towards three prestellar cores and three protostellar cores in Orion B9. We also employed our previous APEX observations of C$^{17}$O, C$^{18}$O, N$_2$H$^+$, and N$_2$D$^+$ line emission, and 870 $μ$m dust continuum emission towards the target sources. The o-H$_2$D$^+$ line was detected in all three prestellar cores, but in only one of the protostellar cores. The corresponding o-H$_2$D$^+$ abundances were derived to be $\sim(12-30)\times10^{-11}$ and $6\times10^{-11}$. Two additional spectral…

ASHES巡天（70 μm暗大质量团块早期阶段ALMA巡天）VIII. 内嵌致密核的动力学性质

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores

本研究基于ASHES巡天数据，分析了12个红外暗云中294个内嵌致密核的动力学性质，揭示了核的质量增长、引力束缚状态及湍流演化规律，支持大质量恒星形成的团块供能情景。

低质量恒星形成区 L1688 中冷致密云核的氘分馏

Deuterium fractionation in cold dense cores in the low-mass star forming region L1688

本文通过多分子谱线成图观测与气-尘化学模型，研究 L1688 区四个无星云核的氘分馏随密度和半径的变化，发现中心氘分馏显著高于包层，并验证了化学模型对含氮和含碳离子氘分馏的预言。

High sensitivity maps of molecular ions in L1544: I. Deuteration of N2H+ and HCO+ and first evidence of N2D+ depletion

Context. The deuterium fraction in low-mass prestellar cores is a good diagnostic indicator of the initial phases of star formations, and it is also a fundamental quantity to infer the ionisation degree in these objects. Aims. With the analysis of multiple transitions of $\rm N_2H^+$, $\rm N_2D^+$, $\rm HC^{18}O^+$ and $\rm DCO^+$ we are able to determine the molecular column density maps and the deuterium fraction in $\rm N_2H^+$ and $\rm HCO^+$ toward the prototypical prestellar core L1544. This is the preliminary step to derive the ionisation degree in the source. Methods. We use a non-loca…

≲2000 au尺度下恒星形成的初始条件：三个早期阶段核的物理结构与NH₃损耗

Initial conditions of star formation at $\lesssim$2000 au: physical structure and NH$_{3}$ depletion of three early-stage cores

本研究通过VLA和GBT的高角分辨率观测，结合Spitzer中红外消光数据，分析三个早期恒星形成核的物理结构与NH₃损耗规律，发现NH₃丰度随核中心密度升高而逐步下降。

宇宙线传播对暗云化学与电离分数的影响

Impact of cosmic-ray propagation on the chemistry and ionisation fraction of dark clouds

本文提出一种高效数值框架模拟暗云中宇宙线传播，结合GIZMO磁流体模拟研究其对化学和电离分数的影响，并给出由可观测示踪物估算电离分数及由H$_2$密度计算宇宙线电离率的解析公式。