论文标题
Oumuamuas穿过分子云
Oumuamuas passing through molecular clouds
论文作者
论文摘要
在短短两年内，1i/Oumuamua和2i/borisov的检测表明，星际物体（ISO）必须以银河系为例。一旦从其父系统中释放出来，这些ISO通过星际空间前往GYR。虽然经常被认为是空的，但星际空间包含以分子云形式最突出的气体和灰尘。进行数值模拟，我们测试ISOS多久交叉这种分子云。我们发现ISO经常通过分子云通过。在太阳能街区，ISO通常在分子云中花费0.1-0.2％的旅程，对于相对慢的ISO（$ <$ 5 km/s），这可能会增加到1-2％，相当于每回合10-20 myr。因此，动态最小的ISO在分子云中花费最长的时间。换句话说，分子云必须主要包含相对年轻的ISO（$ <$ 1-2 GYR）。因此，ISO的播种过程的半衰期比恒星寿命要短得多。随着到银河中心的距离，在MCS中花费的实际时间减少。我们发现，ISO经常通过MC经过，以至于将他们的道路追溯到250 Myr以上的父母之路似乎超出了重点。此外，根据恒星分布的银河中心距离，我们对ISO密度进行了首次估计。
The detections of 1I/Oumuamua and 2I/Borisov within just two years demonstrate impressively that interstellar objects (ISOs) must be common in the Milky Way. Once released from their parent system, these ISOs travel for Gyr through interstellar space. While often imagined as empty, interstellar space contains gas and dust most prominent in the form of molecular clouds. Performing numerical simulations, we test how often ISOs cross such molecular clouds. We find that the ISOs pass amazingly often through molecular clouds. In the solar neighbourhood, ISOs typically spend 0.1-0.2% of their journey inside molecular clouds, for relative slow ISOs ($<$ 5 km/s) this can increase to 1-2%, equivalent to 10 - 20 Myr per Gyr. Thus the dynamically youngest ISOs spend the longest time in molecular clouds. In other words, molecular clouds must mainly contain relatively young ISOs ($<$ 1-2 Gyr). Thus the half-life of the seeding process by ISOs is substantially shorter than a stellar lifetime. The actual amount of time spent in MCs decreases with distance to the Galactic Centre. We find that ISOs pass so often through MCs that backtracing their path to find their parent star beyond 250 Myr seems beyond the point. Besides, we give a first estimate of the ISO density depending on the galactic centre distance based on the stellar distribution.
