论文标题
Ortho-h $ _2 $ D $^+$的Apex观察到Orion B9细丝中的密集核心
APEX observations of ortho-H$_2$D$^+$ towards dense cores in the Orion B9 filament
论文作者
论文摘要
我们使用Apex望远镜观察372 GHz O-H $ _2 $ d $^+（J_ {K_A，\，\，K_C} = 1_ {1，\，0} -1_ {1，1，\，1}）$ to To Tht In Orion B9中的三个Prestellar Cores和三个Protostellar Cores和三个Protostellar Cores。我们还采用了以前对C $^{17} $ O，C $^{18} $ O，N $ _2 $ H $^+$的观察结果，以及N $ _2 $ _2 $ d $ d $^+$线排放，870 $ $ m $ m $ m dust continum for the目标来源。 O-H $ _2 $ d $^+$ $线在所有三个PRESTELLAR核心中都被检测到，但仅在其中一个Protostellar内核中。相应的O-H $ _2 $ d $^+$丰度得出为$ \ sim（12-30）\ times10^{ - 11} $和$ 6 \ times10^{ - 11} $。在观察到的频带中检测到的另外两条光谱线，分别是$ 100 \％$ $和$ 83 \％$的DCO $^+（5-4）$和n $ _2 $ h $^+（4-3）$。发现Orion B9核心与其他低质量密集核心遵守O-H $ _2 $ D $^+$丰度和气温之间的关系一致。随着核心的发展，发现O-H $ _2 $ D $^+$ $ $ $ $ $^+$。 O-H $ _2 $ D $^+$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $，与其他低质量核心的核心核心一致，而对于高质量恒星形成区域的核心核心则大。与在托管原始固体的核心相比，较高的O-H $ _2 $ D $^+$ $ $ $ $ $^+$ $ $^+$ $ $^+$ $ d $^+$ $ d $^+$。使用[O-H $ _2 $ d $^+$]/[N $ _2 $ d $^+$]比率作为进化指标的有效性，该指标已被提议用于大规模团块，在应用于这些目标核心时仍有待确定。总体而言，由于位于猎户座B的动态环境中，Orion B9细丝提供了一个有趣的目标系统来研究基于氘的化学，并进一步观察了诸如Para-H $ _2 $ _2 $ d $ d $^+$和D $ _2 $ _2 $ h $^+$的物种。
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 lines, DCO$^+(5-4)$ and N$_2$H$^+(4-3)$, were detected in the observed frequency bands with high detection rates of $100\%$ and $83\%$, respectively. The Orion B9 cores were found to be consistent with the relationship between the o-H$_2$D$^+$ abundance and gas temperature obeyed by other low-mass dense cores. The o-H$_2$D$^+$ abundance was found to decrease as the core evolves. The o-H$_2$D$^+$ abundances in the Orion B9 cores are in line with those found in other low-mass cores and larger than derived for high-mass star-forming regions. The higher o-H$_2$D$^+$ abundance in prestellar cores compared to that in cores hosting protostars is to be expected from chemical reactions where higher concentrations of gas-phase CO and elevated gas temperature accelerate the destruction of H$_2$D$^+$. The validity of using the [o-H$_2$D$^+$]/[N$_2$D$^+$] ratio as an evolutionary indicator, which has been proposed for massive clumps, remains to be determined when applied to these target cores. Overall, as located in a dynamic environment of Orion B, the Orion B9 filament provides an interesting target system to investigate the deuterium-based chemistry, and further observations of species like para-H$_2$D$^+$ and D$_2$H$^+$ would be of particular interest.
