Many theoretical studies have shown that external photoevaporation from massive stars can severely truncate, or destroy altogether, the gaseous protoplanetary disks around young stars. In tandem, several observational studies report a correlation between the mass of a protoplanetary disk and its distance to massive ionizing stars in star-forming regions, and cite external photoevaporation by the massive stars as the origin of this correlation. We present N-body simulations of the dynamical evolution of star-forming regions and determine the mass loss in protoplanetary disks from external photoevaporation due to far-ultraviolet and extreme-ultraviolet radiation from massive stars. We find that projection effects can be significant, in that low-mass disk-hosting stars that appear close to the ionizing sources may be fore- or background stars in the star-forming region. We find very little evidence in our simulations for a trend in increasing disk mass with increasing distance from the massive star(s), even when projection effects are ignored. Furthermore, the dynamical evolution of these young star-forming regions moves stars whose disks have been photoevaporated to far-flung locations, away from the ionizing stars, and we suggest that any correlation between disk mass and distance from the ionizing star is either coincidental, or due to some process other than external photoevaporation.

许多理论研究表明，大质量恒星的外部光蒸发会严重截断或完全摧毁年轻恒星周围的气态原行星盘。同时，几项观测研究报告了原行星盘的质量与其与恒星形成区域中大质量电离恒星的距离之间的相关性，并引用大质量恒星的外部光蒸发作为这种相关性的起源。我们提出N- 恒星形成区域动力学演化的体模拟，并确定由于来自大质量恒星的远紫外和极紫外辐射导致的外部光蒸发造成的原行星盘质量损失。我们发现投影效应可能很重要，因为靠近电离源的低质量盘状恒星可能是恒星形成区域的前星或背景星。我们在我们的模拟中发现很少有证据表明盘质量随着与大质量恒星的距离增加而增加的趋势，即使忽略投影效应也是如此。此外，这些年轻恒星形成区域的动力学演化将圆盘已被光蒸发的恒星移动到遥远的地方，远离电离恒星，