论文标题
原始棕色矮人的积聚和流出活动
Accretion and outflow activity in proto-brown dwarfs
论文作者
论文摘要
我们使用VLT/SINFONI光谱和光谱图像观测值提出了6级/I Proto-Brown矮人（Proto-BDS）中的积聚和流出活性的近红外研究。光谱显示了与喷气/流出活动相关的几个[FEII]和H $ _ {2} $线的排放，以及PA $β$和BR $γ$线的积聚诊断。 [FEII]线的峰值速度（$> $> $ 100 km S $^{ - 1} $）高于H $ _ {2} $行。 0类Proto-BD在H $ _ {2} $行中显示出强大的排放，但是[FEII]线未检测到，而I类对象在[FEII]和H $ _ {2} $ lines中均显示出排放，这表明从分子到离子分子组成的Jets的进化趋势。在[FEII]和H $ _ {2} $ spectro-images中看到了带有结的扩展发射，用于3个原始BD，而其余的则显示出具有峰值的峰值形态。原始BD的吸积率范围（2 $ \ times $ 10 $^{ - 6} $ - 2 $ \ times $ 10 $^{ - 8} $）msun yr $^{ - 1} $，而质量损失率则在（4 $ \ times $ \ times $ \ times $ \ times $ \ times $^$^{ - 8} $ - 5 $ \ $ \ 5 $ \ $ \ $ \ 10} - 5 $ 10} - 9} yr $^{ - 1} $。这些速率在低质量原恒星的范围内，高于II类棕色矮人。我们发现原始BDS的喷射效率类似于原恒星中的测量。我们已经从原始BDS中检测到的BR7-BR19线进行了研究。 BR13-BR19的上式线条线仅在较早的阶段系统中检测到。不同的Brackett线相对于BR $γ$线强度的比率与情况B重组的预期比率一致。
We present a near-infrared study of accretion and outflow activity in 6 Class 0/I proto-brown dwarfs (proto-BDs) using VLT/SINFONI spectroscopy and spectro-imaging observations. The spectra show emission in several [FeII] and H$_{2}$ lines associated with jet/outflow activity, and in the accretion diagnostics of Pa$β$ and Br$γ$ lines. The peak velocities of the [FeII] lines ($>$100 km s$^{-1}$) are higher than the H$_{2}$ lines. The Class 0 proto-BDs show strong emission in the H$_{2}$ lines but the [FeII] lines are undetected, while the Class I objects show emission in both [FeII] and H$_{2}$ lines, suggesting an evolutionary trend in the jets from a molecular to an ionic composition. Extended emission with knots is seen in the [FeII] and H$_{2}$ spectro-images for 3 proto-BDs, while the rest show compact morphologies with a peak on-source. The accretion rates for the proto-BDs span the range of (2$\times$10$^{-6}$ -- 2$\times$10$^{-8}$) Msun yr$^{-1}$, while the mass loss rates are in the range of (4$\times$10$^{-8}$ -- 5$\times$10$^{-9}$) Msun yr$^{-1}$. These rates are within the range measured for low-mass protostars and higher than Class II brown dwarfs. We find a similar range in the jet efficiency for proto-BDs as measured in protostars. We have performed a study of the Brackett decrement from the Br7-Br19 lines detected in the proto-BDs. The upper Brackett lines of Br13-Br19 are only detected in the earlier stage systems. The ratios of the different Brackett lines with respect to the Br$γ$ line intensity are consistent with the ratios expected from Case B recombination.
