A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars
A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars
复制标题
从 5600 颗 FGKM 恒星寻找兆瓦阈值的激光发射
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
G. Marcy
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文献类型：
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作者：
Nate K. Tellis;G. Marcy
我们搜索了附近 5600 颗恒星的高分辨率光谱，寻找与自然起源不一致且在空间上未解析的发射线，正如对地外光学激光器所期望的那样。这些光谱是用 Keck 10 m 望远镜获得的，包括来自恒星 0.5 角秒以内的光，通常对应于恒星的几个到几十个天文单位，几乎覆盖了从 3640 到 7890 Å 的整个可见波长范围。我们通过将合成激光发射线注入光谱并盲目分析它们以进行检测来建立检测阈值。我们计算所有采样波长和光谱类型的通量密度检测阈值。我们对激光器本身功率的检测阈值范围为 3 kW 至 13 MW，与距恒星的距离无关，但取决于恒星光谱能量分布的竞争“眩光”以及从基准衍射极限 10 m 级望远镜发射的激光的波长。我们没有发现任何来自 5600 颗恒星周围行星区域的此类激光发射。因为它们包含大约 2000 颗地球大小的不冷不热的行星，所以我们排除了银河系的模型，其中超过 0.1% 的温暖的地球大小的行星拥有技术文明，这些文明有意或无意地向我们发射光学激光。突破聆听计划将进行下一代光谱激光搜索，目标是更多恒星，特别是这里被忽视的恒星类型，包括光谱类型 O、B、A、早期 F、晚期 M 和棕矮星，以及天体物理奇异星。
We searched high-resolution spectra of 5600 nearby stars for emission lines that are both inconsistent with a natural origin and unresolved spatially, as would be expected from extraterrestrial optical lasers. The spectra were obtained with the Keck 10 m telescope, including light coming from within 0.5 arcsec of the star, corresponding typically to within a few to tens of astronomical units of the star, and covering nearly the entire visible wavelength range from 3640 to 7890 Å. We establish detection thresholds by injecting synthetic laser emission lines into our spectra and blindly analyzing them for detections. We compute flux density detection thresholds for all wavelengths and spectral types sampled. Our detection thresholds for the power of the lasers themselves range from 3 kW to 13 MW, independent of distance to the star but dependent on the competing “glare” of the spectral energy distribution of the star and on the wavelength of the laser light, launched from a benchmark, diffraction-limited 10 m class telescope. We found no such laser emission coming from the planetary region around any of the 5600 stars. Because they contain roughly 2000 lukewarm, Earth-size planets, we rule out models of the Milky Way in which over 0.1% of warm, Earth-size planets harbor technological civilizations that, intentionally or not, are beaming optical lasers toward us. A next-generation spectroscopic laser search will be done by the Breakthrough Listen initiative, targeting more stars, especially stellar types overlooked here including spectral types O, B, A, early F, late M, and brown dwarfs, and astrophysical exotica.