Podcaster: Richard Drumm

Title: Famous Women Astronomers – Cecilia Payne-Gaposhkin

Organization: 365 Days Of Astronomy

Description:

Hosted by podcast editor Richard Drumm.

Today we feature This is the 365 Days of Astronomy Podcast. Today we bring you another episode in our new series, Famous Women Astronomers, with the story of Dr. Cecilia Payne-Gaposchkin, woman astronomer & astrophysicist who proposed that stars were composed primarily of hydrogen and helium.

Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.

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Transcript:

This is the 365 Days of Astronomy Podcast. Today we bring you another episode in our new series, Famous Women Astronomers, with the story of Dr. Cecilia Payne-Gaposchkin.

Cecilia Helena Payne was born in Wendover, Buckinghamshire, England on May 10th, 1900.

Her father was a fellow of Oxford University and a historian, but he drowned in a canal when she was only 4 years old.

Her mother was Emma Leonora Helena (Pertz) Payne, who was a skilled artist. She raised her 3 children alone after her husband’s death. 

She ensured that all her children got good educations, Cecilia’s brother became an archeologist and her younger sister was an architect.

At age 6 she attended a small girls’ school across the street from her home in Wendover. The school taught her Latin, French, German, and also algebra and some chemistry.

At age 8 she decided to become a scientist. She’d found a flower, a bee orchid, based on a written description that her mother had written about on the Italian Riviera.

In her words:

“For the first time I knew the leaping of the heart, the sudden enlightenment, that were to become my passion. These moments are rare, and they come without warning, on days to be marked with a white stone.”

This is an obsolete idiom that means a very pleasurable day, one that is to be remembered fondly. 

The term comes from the Roman occupation of Britain where a piece of chalk, which is a white stone after all, is used to highlight a day on the calendar. The white cliffs of Dover are chalk, you know…

Bad days were marked with charcoal.

Huh.

Anyway, at age 12 the family moved to London and the young Cecilia attended St. Mary’s College, what we’d call a high school here in the USA. 

It was inferior in many ways to the little school in Wendover, the maths taught there were a year behind what she had already been taught.

So, on her own, she studied coordinate geometry and calculus.

But the school asked her to leave after what we’d consider the Junior year, a year short of graduating. The administration said they couldn’t meet her insatiable curiosity about math and science, but the more likely reason was that she was insufficiently pious. 

She’d once asked a bookbinder to put a bible’s cover on Plato’s book “Apology” to hide her interests from her teachers. But the bookbinder refused the request.

So she then enrolled at the more demanding St. Paul’s Girls’ School and found a much more capable and welcoming environment. She studied music under Gustav Holst himself, who encouraged her to become a professional musician. 

But she was in love with science, so with a rare full scholarship under her arm, at age 19 it was on to Cambridge’s Newnham College she went!

Her major was botany, which was expected of young ladies, but she minored in physics. 

But on December 2nd, 1919, she attended a lecture by Sir Arthur Eddington, the head of the Cambridge University Observatory, where he told of his expedition to the island of Príncipe to verify Einstein’s theory of relativity. 

Afterward she transcribed the lecture in her notebook and didn’t sleep for 3 nights, she was so excited. She later described it this way: “My world had been so shaken that I experienced something like a nervous breakdown.”

So she switched her major to physics and began working at the Cavendish Laboratory in Cambridge.

The rampant sexism she suffered under at Cambridge in Ernest Rutherford’s classes, from both Rutherford and the male students, convinced her to switch her studies to astronomy from physics as soon as possible.

But at Cambridge astronomy is part of the mathematics course of study, not physics. 

Female students were not allowed to major in  mathematics, but she could attend any lectures on any subject she wanted.

So she attended all the astronomy lectures she could while keeping physics as her major. Many of these were Eddington’s lectures.

Eddington didn’t have the antipathy against women students that Rutherford had, there even were several women working at the Cambridge Observatory.

So she went to Eddington and asked him to give her some research to do. 

She was tasked with determining the proper motions of stars in the open cluster M36 in the constellation Auriga, which resulted in her first published scientific paper.

Then Eddington gave her stellar interiors work to calculate and stellar structures to integrate. 

In the British system there is a comprehensive examination after 4 years of study, but there’s nobody tracking what lectures you attend.

These exams lasted all day for several days, too. A veritable marathon of oral and written tests. You have to really know your stuff!

She’d met Harlow Shapley when he’d done his lecture on “The Universe” in London and had asked him if she could work in his program. 

You see, she knew that there would be no astronomy job for her in England, so she applied for a fellowship at Shapley’s Harvard College Observatory, or HCO, in Massachusetts.

Shapley secured for her a $500 stipend and in the fall of ’23 she arrived in the other Cambridge. 

She was based at Radcliffe College, the women’s college that was affiliated with Harvard.

She found the exclusion of women was much less onerous at Harvard than it was in England.  She liked the New England climate better as well, not as cold & damp as it was back at Cambridge, England.

She felt free for the first time to pursue astronomy full time. There was an 11PM lights-out requirement back in England that was not an issue at Harvard & Radcliffe. She could work as late at night as she wanted.

Dr. E.A. Milne, having heard that Cecilia was coming to Harvard Observatory to work with Shapley, had suggested she examine the Saha Theory of Ionization with all the observational material stored at HCO. 

So when she arrived at Harvard College Observatory and Shapley started to steer her toward photometry she told him that she was interested instead in spectroscopy. 

As her position was a fellowship she was completely in charge of what research she did while there. Milne had put the bug in her ear, so-to-speak, and she was interested in the ionization theory.

So she had the run of the plate vault with its thousands of spectral plates being compiled for the Henry Draper Catalog. 

Annie Jump Cannon was classifying spectra at that time, but wasn’t analyzing the lines any further than that, and she graciously allowed Cecilia to work unencumbered.

The Saha Ionization Equation was a fairly new concept, developed by Indian astrophysicist Dr. Meghnad Saha in 1920.

This equation ties the state of ionization of a gas to the gas’s temperature & pressure. 

Dr. Milne and R.H. Fowler had refined the Saha equation and it was this improved version that Cecilia used in her thesis.

As the thesis was nearing completion Shapley convinced Cecilia to pursue a doctorate degree by writing a doctoral dissertation. Her thesis became the needed dissertation.

There wasn’t an Astronomy Department at Harvard until 1931, so the HCO was part of the Physics Department.

There weren’t any astronomy graduate students, so Cecilia was very much on her own. Shapley was her internal graduate advisor, but spectra wasn’t his area of expertise. 

Her external graduate advisor was Henry Norris Russell of Princeton, who’d been Shapley’s doctoral advisor. 

Russell was extremely influential in American astronomical circles, so he was given the final word on doctoral theses.

One of the first things she had to do was develop a way to numerically quantify the spectral lines on the glass plates she had to study.

Silicon was one of the first breakthroughs she found, with its 3 ionized states varying along with a star’s spectral class.

After 2 years’ work she tied the temperature of a star to the intensity of the absorption lines. 

She discovered:

1. That regardless of the star’s spectral type, all stars had a similar elemental composition. And…

2. That hydrogen & helium were by far the most common elements present. Hydrogen was 1,000,000 times more abundant and helium 1,000 times more abundant than expected.

Unfortunately Shapley and especially Russell were firm believers in the status quo, that the stars had the same relative abundances of elements as Earth has.

So Cecilia was pressured by the politics of the day to add additional sentences to page 188 of her thesis: 

To wit:

“The outstanding discrepancies between the astrophysical and terrestrial abundances are displayed for hydrogen and helium. The enormous abundance derived for these elements in the stellar atmosphere is almost certainly not real.”

Shapley had attempted to get her PhD awarded in the Physics Department, but the chairman there refused to do so. So her PhD was in astronomy instead of physics.

She hadn’t gotten a Master’s degree when at Cambridge, so she was quickly awarded one by proxy so that she could get the PhD from Radcliffe.

Harvard still didn’t award PhDs to women, so Radcliffe, the sister institution, was where Cecilia’s doctorate came from. Hers was the first astronomy PhD from there.

Otto Struve, Director of the Yerkes Observatory, called her thesis “undoubtedly the most brilliant PhD thesis ever written in astronomy.”

With the doctorate awarded, her fellowship was at an end. She now needed a job and Shapley offered her a job at HCO as his technical assistant.

So now she had to pursue topics of interest to Shapley and not her own research interests. 

But she was able to pursue some spectral research on the side and wrote a second book, “Stars of High Luminosity.”

In 1933 she traveled to Leningrad to meet with a Russian astronomer to lay the groundwork for a book on variable stars. 

Then on the return leg of the trip she traveled to Gottingen, Germany to an astronomy conference where she met another Russian astronomer. 

This one, Sergei Gaposchkin, was unable to return to Russia because of his politics and was persecuted in Germany because he was Russian. He was caught between a rock and a hard place!

She returned home and was able to convince Shapley to find a position at Harvard for him, she got Gaposchkin a visa as a stateless person and he escaped Nazi Germany.

They married in 1934 and had 3 children over the years.

Cecilia was named a lecturer in astronomy at Harvard in 1938, but her name didn’t appear in the University catalog of courses until 1948. 

When Shapley left HCO in 1952 he was replaced as Acting Director by Dr. Donald Menzel. He became full director 2 years later.

He promptly doubled Cecilia’s wages as Shapley had been compensating her rather poorly for her work.

She & Sergei couldn’t afford childcare and their 3 children often played at the Observatory.

In 1956 she was finally appointed to a full professorship at Harvard, the first woman to hold such a position. 

Several months later she became chairman of the Astronomy Department, the first woman to hold that position too!

She retired in 1966 and wrote her autobiography “The Dyer’s Hand.”  As a member of the staff at the Smithsonian Astrophysical Observatory she continued her researches at HCO until her death of lung cancer in 1979. She’d been a chain smoker for years.

Her legacy includes a prize awarded by the UK’s Institute for Physics. It’s a plasma or space physics research award, the Cecilia Payne-Gaposchkin Medal and Prize.

End of podcast:

365 Days of Astronomy
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