Guillermo Haro

Guillermo Haro Barraza, a Mexican astronomer, helped shape modern observational astronomy in his home country through both his own scientific work and his efforts to create new institutions. On the global stage, he is best known for co-discovering what are now called Herbig–Haro objects.

Born in Mexico City, Haro initially studied philosophy and law at the National Autonomous University of Mexico (UNAM). While working as a reporter for Excélsior, he interviewed astronomer Luis Enrique Erro in 1937, which sparked his interest in the field. Erro was so impressed by Haro’s dedication that he hired him as an assistant in 1943 at the newly founded Observatorio Astrofísico de Tonantzintla. Erro then arranged for Haro to train in the United States, where he worked at the Harvard College Observatory, Case Observatory, Yerkes Observatory, and McDonald Observatory.

After returning to Mexico in 1945, Haro continued at Tonantzintla, where he oversaw the installation of a new 24-31-inch Schmidt camera and began studying extremely red and blue stars. In 1947, he also started working at UNAM’s Observatorio de Tacubaya. Using the Tonantzintla Schmidt telescope, he detected many planetary nebulae toward the Galactic Center and, independently of George Herbig, discovered nonstellar condensations in dense clouds near regions of recent star formation—the Herbig-Haro objects. He and his colleagues found flare stars in the Orion nebula and in stellar aggregates of different ages, a line of research he pursued until his death. Other major projects included a 1961 catalog of 8,746 blue stars near the north galactic pole, created with W. J. Luyten using the 48-inch Palomar Schmidt and a three-color image technique developed at Tonantzintla; at least 50 of those objects later turned out to be quasars. In 1956, he compiled a list of 44 blue galaxies that foreshadowed the work of Benjamin Markarian. Haro also discovered T Tauri stars, one supernova, more than ten novae, and one comet.

Haro was a key figure in Mexican astronomy, not only through his research but also by founding institutions and setting research policies. He became a member of the Colegio Nacional at age 40, the youngest ever. In 1959, he became the first Mexican elected to the Royal Astronomical Society. His students included Silvia Torres-Peimbert and Manuel Peimbert. He founded the Mexican Academy of Sciences (ser