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Title: A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars

Abstract

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,more » 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.« less

Authors:
;  [1]
  1. Astronomy Department, University of California, Berkeley, CA 94720 (United States)
Publication Date:
OSTI Identifier:
22663619
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 153; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BENCHMARKS; DETECTION; DIFFRACTION; DWARF STARS; EMISSION SPECTRA; EMISSION SPECTROSCOPY; ENERGY SPECTRA; FLUX DENSITY; MILKY WAY; PLANETS; RESOLUTION; TELESCOPES; VISIBLE RADIATION; WAVELENGTHS

Citation Formats

Tellis, Nathaniel K., and Marcy, Geoffrey W., E-mail: Nate.tellis@gmail.com. A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA6D12.
Tellis, Nathaniel K., & Marcy, Geoffrey W., E-mail: Nate.tellis@gmail.com. A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars. United States. doi:10.3847/1538-3881/AA6D12.
Tellis, Nathaniel K., and Marcy, Geoffrey W., E-mail: Nate.tellis@gmail.com. Thu . "A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars". United States. doi:10.3847/1538-3881/AA6D12.
@article{osti_22663619,
title = {A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars},
author = {Tellis, Nathaniel K. and Marcy, Geoffrey W., E-mail: Nate.tellis@gmail.com},
abstractNote = {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.},
doi = {10.3847/1538-3881/AA6D12},
journal = {Astronomical Journal (Online)},
number = 6,
volume = 153,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}