From 1911 to 1915, Photographic Stellar Spectrum surveys were carried out by Annie Jump Cannon and Edward Charles Pickering. Anna Mary Palmer who was
Henry Draper's wife financed the study, it was also her husband who was responsible for the star's designation in the
Henry Draper Catalogue with subsequent extension (HD) although it was first designated as BD+29 2979 in the original catalogue that was published in 1863 by
Friedrich Wilhelm Argelander due to its position and brightness of 324,198 stars between +90° and −2° declination in the span of an 11-year observation. A number of
proper motion surveys was published in 1957 where 9,867 stars in the Southern hemisphere where high proper motion was detected. The name BD was taken from a catalogue of the
Bonner Durchmusterung (Bonn Survey) where observations are abbreviated as BD. Latter study expansions were carried out by the Cape Photographic Durchmusterung observatory in
Córdoba, Argentina and further extensions by Henry Lee Giclas who designated the star as G 181-34 in the
Giclas catalogues. From 1990 to 1993, HD 156668 was observed at least twice and was featured at the 6th annual catalog of the Tokyo Photoelectric Meridian Circle (PMC) where it is one of 6649 stars observed. ==Planetary system==