Image Credit: Cornell University
This afternoon, I learned that renowned astronomer Edwin Salpeter died last Tuesday from leukemia at his home in Ithica, New York.
Salpeter was one of those astronomers that few in the public had heard about, but who had a tremendous impact on the science of astronomy. I never met Salpeter, but I am well aware of his impact on our field. Most of us younger astronomers first become aware of Salpeter's name through what we cann the "initial mass function," which is a simple mathematical equation giving the number of stars of each mass arising from stellar nurseries, like the Orion Nebula. Salpeter's equation describes how there are a lot more little stars than big stars. His equation is still in common use some 50 years later.
Salpeter's biggest contribution may have been in understanding how stars burn helium into carbon. To make carbon requires three helium atoms smashing together almost simultaneously; it took some tricky quantum physics work to figure this out. Along with Nobel-prize winning physicist Hans Bethe, Salpeter developed the mathematical framework for some types of two-particle systems (but don't ask me to explain it, because I personally have never studied this field of physics). Salpeter's list of achievements goes on; running through his obituary and his webpage, I found myself reading about an important bit of astronomy research and saying, "I didn't know he worked on that." It's quite impressive.