论文标题
快速搜索情节原子氢 - i：年轻的行星星云IC 4997
FAST search for circumstellar atomic hydrogen--I: the young planetary nebula IC 4997
论文作者
论文摘要
我们使用中国圭村的五百米孔球形射电望远镜（FAST），我们检测到年轻的行星Nebula IC 4997中的21cm中性原子氢吸收。这些吸收来自与Na I D系相关的壳。 H I Shell的质量为$ 1.46 \ times10^{ - 2} $ m $ _ \ odot $，动态时代为990yr。 H I的色谱柱密度估计为$ 7.1 \ times10^{20} $ cm $ $^{ - 2} $，可以很好地解释它在离子化的星云周围的光解离区域，受H $ _2 $的自我屏蔽的限制。我们发现原子与离子化的氢比为0.6，这表明H极大地有助于整体螺旋质量。
Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Guizhou, China, we detect the 21cm neutral atomic hydrogen absorption in the young planetary nebula IC 4997. The absorption arises from a shell also associated with Na I D lines. The H I shell has a mass of $1.46\times10^{-2}$ M$_\odot$ and a dynamic age of 990yr. The column density of H I is estimated to be $7.1\times10^{20}$ cm$^{-2}$, which can be well explained in terms of a photodissociation region around the ionized nebula, limited by self shielding of H$_2$. We find that the atomic-to-ionized hydrogen ratio is 0.6, suggesting that H I substantially contributes to overall nebular mass.
