论文标题
在M型矮人居住区中的系外行星的生活？
Life on Exoplanets In the Habitable Zone of M-Dwarfs?
论文作者
论文摘要
由于宿主恒星的长寿，银河系中这样的恒星的突出以及在M-Dwarfs周围发现的明显过剩的陆地行星，在M-dwarf恒星周围可居住的区域中绕行的系外行星一直是寻找生命的主要目标。但是，在这些系统中，M矮人的恒星活动和经常锁定的行星的恒星活动提高了有关这些行星的可居住性的问题。在这封信中，我们研究了可能存在的另一个重大挑战：这些系统似乎缺乏将小行星运送到可居住的陆地行星所需的建筑，而小行星影响可能在生命的起源中起着至关重要的作用。生产稳定的小行星带和燃气盘耗散后小行星的后期输送的最广泛接受的机制需要一个巨大的行星，即雪线半径。我们表明，在其恒星宜居区中没有行星的观察到的系统也包含一个巨大的行星，因此不太可能具有稳定的小行星带。我们将观察到的巨型行星相对于雪线半径的位置作为恒星质量的函数，发现M-dwarfs周围的雪线半径外有大量的巨型行星。因此，通常可以在M矮人周围形成小行星皮带。但是，我们发现M-dwarf周围的多星际系统体系结构可能与更大的恒星周围的架构大不相同。
Exoplanets orbiting in the habitable zone around M-dwarf stars have been prime targets in the search for life due to the long lifetimes of the host star, the prominence of such stars in the galaxy, and the apparent excess of terrestrial planets found around M-dwarfs. However, the heightened stellar activity of M-dwarfs and the often tidally locked planets in these systems have raised questions about the habitability of these planets. In this letter we examine another significant challenge that may exist: these systems seem to lack the architecture necessary to deliver asteroids to the habitable terrestrial planets, and asteroid impacts may play a crucial role in the origin of life. The most widely accepted mechanism for producing a stable asteroid belt and the late stage delivery of asteroids after gas disk dissipation requires a giant planet exterior to the snow line radius. We show that none of the observed systems with planets in the habitable zone of their star also contain a giant planet and therefore are unlikely to have stable asteroid belts. We consider the locations of observed giant planets relative to the snow line radius as a function of stellar mass and find that there is a population of giant planets outside of the snow line radius around M-dwarfs. Therefore, asteroid belt formation around M-dwarfs is generally possible. However, we find that multi-planetary system architectures around M-dwarfs can be quite different from those around more massive stars.
