‘Grandeur in this view of life’: N-body simulation models of the Galactic habitable zone
‘Grandeur in this view of life’: N-body simulation models of the Galactic habitable zone
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“这种人生观的伟大”：银河宜居区的 N 体模拟模型
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发表时间：
2016
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通讯作者：
S. Schindler
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作者：
B. Vukotić;Dominik Steinhauser;G. Martinez;M. Ćirković;M. Micic;S. Schindler
我们在 GADGET2 N 体 SPH 代码中提出了一种孤立的类似银河系的模拟。银盘恒星形成率（SFR）表面密度和指示太阳邻域的恒星质量被用作阈值来模拟生命友好环境中恒星质量的分布。 SFR 和恒星成分密度是通过对映射在银河平面上的 2D 网格上的 GADGET2 粒子属性进行平均来计算的。在 $10$ Gyr 的模拟时间跨度内，可能适宜居住的恒星质量表面密度的峰值从 $10$ kpc 圆柱半乳心距离移动到 $15$ kpc。在 10 美元 Gyr 的情况下，模拟结果表明以下内容。几乎一生都在适宜居住的条件下度过的恒星粒子通常位于距离银河系中心 $sim16$ kpc 处，年龄为 $sim 3$ Gyr。恒星粒子在其 4-5$ Gyr 的漫长寿命中，有 90 \%$ 是在适宜居住的条件下度过的，它们也主要出现在银盘的郊区。在典型的太阳系银河系中心距离 $8-10$ kpc 处可以找到不到 $1 \%$ 的这些粒子。我们的结果表明，孤立螺旋星系的演化很可能导致银河文明出现在比太阳年轻的恒星宿主周围的银盘边缘。
We present an isolated Milky Way-like simulation in GADGET2 N-body SPH code. The Galactic disk star formation rate (SFR) surface densities and stellar mass indicative of Solar neighbourhood are used as thresholds to model the distribution of stellar mass in life friendly environments. SFR and stellar component density are calculated averaging the GADGET2 particle properties on a 2D grid mapped on the Galactic plane. The peak values for possibly habitable stellar mass surface density move from $10$ to $15$ kpc cylindrical galactocentric distance in $10$ Gyr simulated time span. At $10$ Gyr the simulation results imply the following. Stellar particles which have spent almost all of their life time in habitable friendly conditions reside typically at $sim16$ kpc from Galactic centre and are $sim 3$ Gyr old. Stellar particles that have spent $ge 90 \%$ of their $4-5$ Gyr long life time in habitable friendly conditions, are also predominantly found in the outskirts of the Galactic disk. Less then $1 \%$ of these particles can be found at a typical Solar system galactocentric distance of $8-10$ kpc. Our results imply that the evolution of an isolated spiral galaxy is likely to result in galactic civilizations emerging at the outskirts of the galactic disk around stellar hosts younger than the Sun.