"Hadar" is more commonly known as "Beta Centauri" and is the tenth brightest star in the night sky.
Beta | Tau Beta Pi | Alpha Centauri | Phi Beta Sigma | beta | Zeta Beta Tau | TGF beta 1 | Beta Gamma Sigma | The Beta Band | Tau Beta Sigma | Sid Meier's Alpha Centauri | Phi Beta Kappa Society | Beta Israel | TGF beta receptor 2 | National Beta Club | Beta (plant) | Beta (letter) | Beta-Hexachlorocyclohexane | Beta Flight | Beta Alpha Psi | VHS or Beta | Steroid 11-beta-hydroxylase | Proxima Centauri | Gamma Phi Beta | Epoetin beta | Beta (typeface) | Beta Sigma Phi | Beta-galactosidase | beta decay | Beta Crucis |
in 1897 he discovered the presence of oxygen in spectrographs from Beta Scorpii, Beta Canis Majoris, Beta Centauri, and Beta Crucis.