SETI bioastro: P. C. Keenan

From: Larry Klaes (
Date: Thu Apr 27 2000 - 12:30:40 PDT

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Date: Thu, 27 Apr 2000 10:24:10 -0600
Reply-To: History of Astronomy Discussion Group <HASTRO-L@WVNVM.WVNET.EDU>
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From: "Michael E. Bakich" <universe@DZN.COM>
Subject: P. C. Keenan

Hello all.

I just received word from Brent Archinal that Phillip C. Keenan passed away
today. For those of you not familiar with him or his work, when someone
refers to the MK system of spectral classification, the "K" is for Keenan.
His specialty was late-type spectra.

While at the Ohio State University, I was fortunate to take two classes
from Dr. Keenan. One was "Stellar Astrophysics" and the other was "The
History of Astronomy." Both were great classes, but the History class was
truly special. I can still remember him passing around cuneiform tablets
(from the OSU collection) showing early records of the appearances of
Venus. You don't get that every day! Forget the education, his stories were
worth the price of admission. Like the time he diaphragmed the 40-inch
Yerkes refractor down to 1/4 inch to obtain a solar spectrum. Talk about

Keenan was a soft-spoken man (I always made certain to sit up front in his
classes) but passionate about astronomy. Once, after a run on the 32-inch
at Perkins Observatory, I was measuring some spectra. Dr. Keenan walked in
and commented on the unusual nature of the spectrum on the plate which I
was holding. He only glanced at it from afar but correctly identified it as
a late M giant with weak emission lines. The man knew his stuff.

Dr. Keenan was 92. He lived a full life, completely enmeshed in the subject
he loved so much. He will be missed.

With fond remembrances,


- - - - - - - - - -

Astronomical Society

         Philip C. Keenan, whose groundbreaking work in stellar
classification punctuated the longest publishing career in modern
astronomy, died Thursday in Columbus, OH. He was 92.

         An emeritus professor of astronomy at Ohio State University for 24
years, Keenan never stopped expanding scientists' understanding of the
nature and evolution of stars.

         He devoted most of his 71-year career to classifying stars by
spectrum. In a photograph, the spectrum of light that emanates from a star
appears as a series of tiny lines, like a bar code in miniature.

         Each type of star has its own unique sequence of bright and dark
lines, and Keenan could recognize any type of star with a simple glance at
its spectrum.

         With colleagues William Morgan and Edith Kellman, Keenan compiled
the premier atlas of stellar spectra in 1943, cataloging over 1,000 types
of stars. Budding astronomy students still turn to that work, titled "An
atlas of stellar spectra, with an outline of spectral classification," to
learn the basics of stellar spectroscopy today.

         The system of classifying stars by spectrum came to be called the
"MKK system" after Keenan and his co-authors, and it provided the
fundamental observational framework for all stellar classification to

         Keenan's most recent collaborator, Cecelia Barnbaum of Valdosta
State University, GA, attested to his unfailing humor, especially his
tendency to joke about death with a light heart.

         The two met in 1995, when Keenan asked her to join him in creating
a new atlas of stars with atmospheres rich in carbon, aptly named "carbon
stars." When she agreed, the 87-year-old climbed into his car and drove for
six days from Columbus to the National Radio Astronomy Observatory in
Charlottesville, VA, to introduce himself in person.

         Barnbaum remembers how he took her hand upon arrival and said with
a wry smile, "Now, I want you to understand that I fully expect to drop
dead any day now, so I might not be here to finish the atlas."

         But he did finish it, and with its publication in the Journal of
the Astronomical Society of the Pacific in 1997, Keenan claimed the title
of longest-publishing astronomer.

         He first published in that very same journal in 1929, as an
undergraduate student at the University of Arizona. Back then, he
scrutinized the color of the moon during eclipses. At the time, astronomers
thought different colors would indicate weather conditions on the parts of
the earth that cast the shadow.

         Seventy years later, as he and Barnbaum sat in a restaurant in
downtown Columbus discussing their latest research project, he echoed the
joke from their first meeting. Stomach problems forced him to limit most
meals to thin soup and bread, she said, but that day he spoke to her over a
hamburger with relish.

         She laughed, remembering: "He took a bite and said, 'I'm sure this
is going to kill me, but it's going to be worth it.'"
His most recent work with Burnbaum appeared in the Astrophysical Journal in

         One of Keenan's contemporaries, Daniel Popper, professor emeritus
of astronomy at the University of California, Los Angeles (UCLA), died late
last year. Keenan was a postdoctoral researcher at UCLA when Popper was a
graduate student. Popper went on to develop ways to determine the mass and
radius of stars in binary systems.

         Keenan told Barnbaum that when he and Popper worked together, the
two often took breaks from academe to ride horses through the plains of
Texas. "Whenever I think of them together, that's how I picture them,"
Barnbaum said.

         Keenan was born in Bellevue, Pennsylvania on March 31, 1908 to
Charles Keenan and Evelyn (Childs) Keenan, and her maiden name became their
son's middle name.

         He received his bachelor's and master's degrees from the
University of Arizona in 1929 and 1930. He then garnered a Ph.D. from the
University of Chicago in 1932, where he worked as an instructor from 1936
until 1942. After four years' employment as a physicist with the Navy
Bureau of Ordnance, he became Assistant Professor at the Ohio State
University in 1946. He worked at Perkins Observatory in Delaware, OH, with
a telescope jointly operated by Ohio State and Ohio Wesleyan University.

         In 1976, Keenan retired as professor, but he continued his
research through 1999.

         "Philip's dedication to astronomy, his long career, and his
extensive knowledge of the field were an inspiration to the members of the
Ohio State Astronomy Department, and especially to the students who knew
him," said Patrick Osmer, chair of the department.

Osmer characterized Keenan's interest in stars cooler than our sun -- stars
whose complex spectra contain a large number of atomic and molecular
features. These luminous cool stars are in the advanced stages of their
evolution, Osmer explained, and eject their outer atmosphere into space as
they complete their life cycles, contributing to the evolution of galaxies
like our Milky Way.

         The Department of Astronomy plans to host a gathering at Perkins
Observatory in the next few weeks, at which time they will scatter Keenan's
ashes on the grounds.

         The Perkins garden fed Keenan's only obsession other than
astronomy. He enjoyed tending the plants along with his academic pursuits
as long as he possibly could.

         Keenan never married -- if asked why, he joked that he thought no
one would put up with him -- but his life remained full with research and
student mentoring, and gardening at Perkins.

         In an interview in 1997, Keenan looked forward to technology
producing even more accurate means to further classify stars in the future.
He hoped others would follow his work.

         "Of course, I won't be around for that, but I hope somebody will
take it up," he said. "Now all the emphasis is on studying black holes and
active galaxies and that sort of thing, which is all very well, but I think
some of the older lines of work should be continued also -- especially when
they're developing in new directions."

         Keenan also revealed the secret behind his long life and research
throughout retirement:

         "I think it would have been a mistake to stop my work as soon as I
retired. I think I would've gotten bored. Work helps keep you alive, and
there's much work to be done."

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