Boyle, born March 4, 1943, at Everett, Massachusetts, completed degrees in theology and the liberals arts at Boston College (Chestnut Hill, Mass.) in 1965, and in philosophy and physics at St. Louis University in 1967. He obtained his doctorate in astronomy at Georgetown University, Washington, D.C., in 1971, with a study on solar photospheric abundances by spectrum synthesis.

A member of the Society of Jesus since 1961, he completed ministerial theology studies and was ordained to Roman Catholic priesthood in 1975. After nine months in 1975-76 as a post-doctoral research astronomer at the Manila Observatory at Quezon City (Manila), Philippines, he worked at Emmanuel College in Boston and Boston College, where he worked from 1978-81 on contract for the Air Force Geophysics Lab in solar-terrestrial physics. Boyle joined the Vatican Observatory Research Group as staff astronomer in observational astronomy when the group was established in Tucson in 1981. He serves as telescope scientist for the new Vatican telescope, along with his counterpart from Steward Observatory, Richard Cromwell.

He specializes in observational astronomy, in studies of stellar populations in Milky Way Galaxy star clusters, and in research of the atmospheres of giant red stars. He is a member of the American Astronomical Society, the American Geophysical Union and the International Astronomical Union. He also served as Dean of the 1993 and 1995 Vatican Observatory Summer Schools in Castel Gandolfo.

VATT science: Boyle studies the evolution of the Milky Way Galaxy by using multi-color photometry to analyze the metallicity of stars (the chemical elements observed in stars, which first burn hydrogen to helium and then to progressively heavier elements). Metallicity is a key to determining star ages and the rate of star production.

One of the long-term survey programs for which Boyle is using the new Vatican telescope is a study of the population of stars in the Milky Way Galaxy using the Vilnius photometric system, a technique used to measure certain stellar spectral regions that contain the best astrophysical information. This system was developed more than 20 years ago by Vytas Straizys, now Director of the Vilnius Observatory at Vilnius, Lithuania. Straizys is among those who is collaborating with Boyle on this project.

Specifically, says Boyle, their observations will test a popular 3-part model of the structure of the Milky Way. "The model says that the Milky Way consists of a dense, thin disk of new stars, forming out of gas clouds and of younger stars, including our sun, which are found in the galactic plane. Another part is the much more diffuse, spheroidal halo of older stars outside the galactic plane, the 'galactic halo.' A third part, which has received more attention in the last 15 years, is the thick disk of stars immediately surrounding the thin disk. Few studies suggest the thick-disk stars are older than the thin-disk stars, but only observations of many stars will really tell whether the thick disk is a part of the Milky Way truly distinct from the thin disk. It could be the that the thick disk is a phase where the galaxy paused as the halo collapsed into the thin disk. Or, the thick disk could be the result of an encounter with another galaxy which injected energy into the thin disk, heating stars with kinetic energy so they were thrown into a thick disk. Astronomers have yet to settle whether our galaxy is a two-part or a three-part model."