31. Secondary, ? 1694 B is a spectroscopic binary both A-type main sequence star. 32. HD 203338 is itself a spectroscopic binary with components Aa and Ab orbiting every 280 years. 33. In 1910, this was determined to be a single-lined spectroscopic binary star system. 34. Blanco 1 contains approximately 300 stars, around 170 of these being brighter than spectroscopic binaries . 35. In 1958, American astronomer Horace W . Babcock discovered that this is a spectroscopic binary star. 36. "' 31 Camelopardalis "'is an eclipsing spectroscopic binary in the constellation Camelopardalis. 37. The primary star consists of a double-lined spectroscopic binary with a more distant tertiary companion. 38. The spectroscopic binary companion star is an A2V dwarf of about 2 solar masses and 30 luminosity. 39. "' Xi Cygni "'is a spectroscopic binary star in the constellation Cygnus. 40. "' 35 Cygni "'is a spectroscopic binary star in the constellation Cygnus.
