Mario Hamuy

Mario Hamuy is a Chilean Astronomer and Professor of Astronomy at the University of Chile and Cerro Calan Observatory. He is well known for his observational work on all classes of supernovae, especially the use of Type Ia and Type II supernovae as measures of cosmic distance. He was a student in astronomy and physics at the University of Chile working with Jorge Melnick. In February 1987, he came to the Cerro Tololo Inter-American Observatory and within a few days of his arrival when the Type II supernova SN1987A exploded in the Large Magellanic Cloud, he began a major campaign at CTIO to monitor this important supernova.

In 1989, in collaboration with Jose Maza, Mark M. Phillips, and Nicholas Suntzeff, he began the Calan/Tololo Supernova Survey which led to the pioneering work on the standard candle luminosities of Type Ia supernovae. This work led to the precise measurements of the Hubble Constant H₀ and the deceleration parameter q₀, the latter indicating the presence of a dark energy or cosmological constant dominating the mass/energy of the Universe.

In graduate school at the University of Arizona at the Steward Observatory working with Professor Phil Pinto, he changed his focus to the study of core collapse supernovae, in particular using Type II supernovae to measure geometric distances using the Baade-Wesselink method, also called the expanding-photosphere method (EPM). With Pinto, he invented a semi-empirical method to measure distances to Type II events, called the Standard Candle method , which improved the distance accuracies over EPM.

In 2011, asteroid 109097 was named after him.