论文标题
星际彗星2i/borisov的水生产率和活动
Water production rates and activity of interstellar comet 2I/Borisov
论文作者
论文摘要
我们使用Neil Gehrels-Swift天文台的紫外线/光学望远镜观察了星际彗星2i/Borisov。我们在周围和之后的六个时期（-2.56 au至2.54 au）的六个时期处获得了OH气体和灰尘的图像。水生产率从$（7.0 \ pm1.5）\ times10^{26} $分子s $^{ - 1} $在2019年11月1日至$（10.7 \ pm1.2）\ times10^times10^{26} {26} $ s $ s $ s $ s $^{ - 1} $ new IS的速率。在各种木星家族彗星的较慢的末端。圆锥体后，12月21日的水生产率降至$（4.9 \ pm0.9）\ times10^{26} $分子s $^{ - 1} $，这比所有先前观察到的彗星的速度都要快得多。我们的升华模型将细胞核的最小半径限制在0.37 km，并指示至少55％的表面分数。 $ a（0）fρ$计算显示57.5至105.6 cm之间的变化，近乎围珠之前的趋势峰值峰值峰值，低于以前的和并发公布的值。该观察结果证实，相对于水，2i/borisov是碳链耗尽并富含NH $ _2 $的。
We observed the interstellar comet 2I/Borisov using the Neil Gehrels-Swift Observatory's Ultraviolet/Optical Telescope. We obtained images of the OH gas and dust surrounding the nucleus at six epochs spaced before and after perihelion (-2.56 AU to 2.54 AU). Water production rates increased steadily before perihelion from $(7.0\pm1.5)\times10^{26}$ molecules s$^{-1}$ on Nov. 1, 2019 to $(10.7\pm1.2)\times10^{26}$ molecules s$^{-1}$ on Dec. 1. This rate of increase in water production rate is quicker than that of most dynamically new comets and at the slower end of the wide range of Jupiter-family comets. After perihelion, the water production rate decreased to $(4.9\pm0.9)\times10^{26}$ molecules s$^{-1}$ on Dec. 21, which is much more rapidly than that of all previously observed comets. Our sublimation model constrains the minimum radius of the nucleus to 0.37 km, and indicates an active fraction of at least 55% of the surface. $A(0)fρ$ calculations show a variation between 57.5 and 105.6 cm with a slight trend peaking before the perihelion, lower than previous and concurrent published values. The observations confirm that 2I/Borisov is carbon-chain depleted and enriched in NH$_2$ relative to water.
