Here’s where the new discovery becomes intriguing: The spectroscopic data also show a broad emission line from ionized hydrogen, called hydrogen alpha, that does not move together with the other lines in the star’s spectrum. Instead, the line comes from something moving only one-eighth the speed of the star in its orbit. What’s more, its motion is opposite the star’s, moving toward Earth as the star moves away and vice versa. These characteristics are just what you would expect for the star’s binary companion.