Astronomy and Space
Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her) is a spectroscopic binary in the constellation of Hercules. Its light produces to us apparent magnitude 3.12, as such the third-brightest star in the large, fairly dim constellation. Based on parallax measurement taken during the Hipparcos mission, it is approximately 23.1 parsecs (75 light-years) from the Sun.
Dark matter.
Frederick L. Scarf.
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