发表机构
Steward Observatory, The University of Arizona（斯图尔德天文台，亚利桑那大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究以巴纳德10区域的11个低质量无恒星核为对象，观测氘代分子，发现氘代甲醛存在气相形成，不同纤维的核氘分馏有差异，提示无恒星核的氘代特征可用于研究其演化。
AI 中文摘要
无恒星核中分子的氘分馏对其动力学历史敏感，近期磁流体动力学模拟显示这类历史具有极大的多样性。甲醛（H$_2$CO）和甲醇（CH$_3$OH）的氘代同位素体可探测简单有机分子中的氘分馏。本完整调查针对金牛座分子云中小而宁静的巴纳德10（B10）区域内的11个低质量无恒星核，使用亚利桑那天文台12米望远镜对o/pH$_2$CO、HDCO、pD$_2$CO、A/E-CH$_3$OH、CH$_2$DOH的跃迁及致密气体示踪剂N$_2$H$^+$进行观测，探测率达100%。HDCO和pD$_2$CO的柱密度与氘分馏和 grain表面氘代示踪剂CH$_2$DOH无关联，表明氘代甲醛存在显著的气相形成过程。观测到的氘分馏与演化指标（如核中心密度）或物理条件（如核质量）无关联，还发现西北纤维内的核，其氘分馏低于另外两个纤维中密度相似的核，这可能指示不同纤维间及纤维内部存在差异化的核演化。将B10样本的氘分馏与不同演化阶段的已发表源对比，提示D$_2$CO可能继承自无恒星核，但需更多有机氘代调查以最终确定这种继承关系。
英文摘要
The deuterium fractionation of molecules in starless cores is sensitive to their dynamical histories, which recent magnetohydrodynamical simulations have shown to be extremely varied. The deuterated isotopologues of formaldehyde (H$_2$CO) and methanol (CH$_3$OH) probe deuterium fractionation in simple organic molecules. This complete survey targets 11 low-mass starless cores in the small, quiescent Barnard 10 (B10) region of the Taurus Molecular Cloud. The cores were observed using the 12m Arizona Radio Observatory telescope with a 100% detection rate in transitions of o/pH$_2$CO, HDCO, pD$_2$CO, A/E-CH$_3$OH, and CH$_2$DOH and the dense gas tracer N$_2$H$^+$. The HDCO and pD$_2$CO column densities and deuterium fractions are not correlated with those of the grain-surface deuteration tracer CH$_2$DOH, indicating significant gas-phase formation of deuterated formaldehyde. The observed deuterium fractions do not correlate with evolutionary indicators (e.g. core central density) or physical conditions (e.g. core mass). We also find that cores within the northwestern filament have lower deuterium fractions than cores of similar densities in the other two filaments. These could indicate differential core evolution both between and within entire filaments. Comparing the deuterium fractions of the B10 sample to published sources across different evolutionary stages suggests the inheritance of D$_2$CO from starless cores, although more surveys of organic deuteration are needed to conclusively determine inheritance.
CommentsAccepted for publication in PASP. 46 pages, 21 figures
