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Cecilia Helena Payne-Gaposchkin: A Master of Stellar Astronomy
Cecilia Payne was born in Buckinghamshire, England on May 10th, 1900. She was the eldest child of Edward John Payne, a London barrister, historian, and scholar at Oxford and Emma Leonora Helena Payne from Coblenz, Prussia, granddaughter of Hanoverian scholar and Parliament member, Chevalier G.H. Pertz. Edward died when Cecilia was just four years old and her mother worked as a painter and a musician to support the children. It was early in her life that Emma introduced her children, Cecilia, Humfry and Lonora to classic literature.
By the time Cecilia was a teenager, she was fluent in Latin, French, and German. There was an early indication of her love of science and math, particularly algebra and botany. During her time at school in London, Cecilia was introduced to, and inspired by, the works of Thomas Huxley, Emmanuel Swedenborg, and Sir Isaac Newton. She delighted in pushing her mind to, and beyond, it’s expected boundaries.
Cecilia's academic life started in 1919 when she won a scholarship to Newham College, an affiliate of Cambridge College. Her studies began with physics, botany, and chemistry. She switched majors several times, but, after a lecture given by Sir Arthur Eddington on Einstein's theory of relativity she became entranced with astronomy and changed her major for the final time. Eddington was the Newham college foremost astronomy expert and he took Cecilia Payne under his wing.
It is almost ironic that Einstein's theory of relativity became more than a theory because of Payne-Gaposchkin. Due to the research she was conducting on a project in the 1920s that involved reexamining the ways spectroscopes collected data, Payne determined that the sun was 90% hydrogen, and the remaining 10% mostly helium. This theory could be applied to the heat and the sun and would solve the quandary Einstein was having that seemed to be showing the sun as mostly iron or uranium.
Payne filled her course schedule with as many astronomy courses as she could and presided over the Newham College Astronomical Society. Her first night using the telescope at the college, she unintentionally frightened the night assistant. In later recollections Payne says he "flew down the stairs, gasping." It was not so much having an unexpected person in the observatory, as it was that the person was a woman and she was asking questions that frightened him. She was not deterred in the slightest. She even set up her own telescope to monitor the night sky on her free time, free from the startled assistant.
She still frequented the college observatory. It was through the observatory that she met astronomer Edward Milne. They became and remained close friends over the years. She had other friends at college, mostly art majors who she tried to pull into her excitement for astronomy. Though she later remarked much of the theories were lost on them, they frequently listened. One of her friends later said that she despised chairs, but when she lay on her back she would discuss anything from ethics to making cocoa.
One of her teachers was Ernest Rutherford, who later helped reveal the structure of atoms. He was cruel to Payne and frequently tried to get the men in the class to laugh at her. This was expected and even encouraged, so Payne had to learn early on how to hold her own.
To the novice, stars all seem the same. They may merge into constellations, thus triggering a memory in the mind of mankind, but these constellations are merely accidental. The randomness of the stars and their distance from earth, affects the apparent brightness of each star we see in the sky. It was this randomness that is said to have been so attractive to Payne. It was this that is said to have driven her pursuit of the study of celestial bodies.
Though she completed her course work in 1923, women were not allowed to receive formal degrees. So all of her education lacked the paper to back it up. In England, and the rest of the United Kingdom in 1925, the option for women to obtain Masters degrees and higher was limited, so Payne tried for a Pickering Fellowship through Harvard College Observatory. The Pickering Scholarship was one of the few awards at the time which was reserved exclusively for female students. Upon receiving the award, Payne packed up her belongings and moved to the United States. The rest of her career was spent in Boston, MA. She was later quoted as calling the city her "stony-hearted stepmother."
Payne worked under the guidance of the director of the Harvard College Observatory, Harlow Shapley. In his 1969 autobiography Through Rugged Ways to the Stars, Harlow Shapley reminisces about Cecilia Payne: “Cecilia Payne (now Cecilia-Payne-Gaposchkin) was and is a genius type of person. She got our first doctor’s degree in astronomy by applying some brand-new astrophysical ideas to stellar spectra. She showed that, in spite of the diversity of spectral types, stars are pretty much all made of the same atoms. She is one the two or three leading women astronomers of the world and has been for the past thirty years.” She continued her study of astronomy at Harvard, while splitting her time with the Harvard College Observatory. It was with the work on her doctoral thesis that Payne took the first step towards the discovery that would make her a person of note in the field of astronomy.
Her thesis, called Stellar Atmospheres, proposed a new formula for the composition of stars which was based on the theory of the abundance of helium and hydrogen within the universe. Payne was the first person to propose that the simplest element, hydrogen, was actually the most abundant element in the universe. She suggested that the range in strength, between stars, the absorption lines of the stellar spectra were due to different temperatures and not on a varying chemical composition as previously thought. Her thesis expounded on the work of Indian physicists Meghnad Saha, which theorized that there was a correlation between ionization of stars to their temperature and chemical density.
Though her proposal has since become the basis for the analysis of the cosmos, she was at the time persuaded to write a less definitive statement by her male supervisors, particularly Henry Russell Norris. Years later, Norris came to the same conclusion and therefore received credit for the discovery. Her conclusion did reach formal acceptance during her lifetime, in 1929, but to this day, she is still not formally credited with her discovery.
Hydrogen is the most abundant element in the Universe
When Cecilia Payne came onto the scene at Harvard the composition of the sun and there for most of the known Universe was not well understood. It was believed that stars had basically the same chemical composition and relative abundance of elements as the Earth. This assumption was based on the relatively new science of spectroscopy. It was Payne’s work in her Ph.D. Thesis that challenged this convention that made her work so important to science.
In 1859, Gustav Kirchoff and Robert Burnsen in Germany observed the spectra of heated chemical elements and found that each element had its own characteristic set of spectral lines. This gave each element a unique identifier in their spectra. In 1863, the English scientist William Huggins observed many of these same lines in the spectra of stars. This was important because this implied that stars were made of the same elements that were found on earth. Unfortunately, this new science of spectroscopy was not very good at determining the abundance of the elements in the spectra. This shortcoming of this technique lead to incorrect assumptions about the composition of the stars.
By observing spectra from several stars, astronomers had identified elements like calcium and iron as responsible for some of the most prominent lines. The natural conclusion from these observations was that stars was that the heavy elements were among the major constituents of the stars. The eminent Professor of Astronomy at Princeton University, Henry Norris Russell, conclude that if the Earth’s crust were heated to the temperature of the sun, it’s spectrum would be very similar to what is observed for that of the Sun.
By the time Payne arrived at Harvard a comprehensive study of stellar spectra had long been underway lead by Annie Jump Cannon. Herself and the other lady “computers” of the Harvard College Observatory had sorted the spectra of several hundred thousand stars into seven distinct classes. She devised an ordering scheme based on difference in the spectral features. Astronomers assumed that the difference in spectra classes were due to different temperatures within the stars.
The new burgeoning science of quantum physics explained that the pattern of spectral features for an element was due to the electron configuration of the individual atoms. At higher temperatures, these electrons where stripped away from the nucleus of the atom, thus creating an “ion”. The Indian physicist M.N. Saha had recently explained how the temperature and pressure in the atmosphere of a star effected the amount of ionization that occurred.
As part of her thesis research Payne had begun to measure the absorption lines in stellar spectra. She showed that the wide variation in stellar spectra was due mainly to different ionization states of the atoms at elevated temperatures. The differences in spectra was due to the temperature differences not the differences in relative abundance. She discovered that the composition of a star was predominantly the light gases elements hydrogen and helium. This new revelation was not well received by the existing scientific community. All the heavier elements which are primarily present in the Earth only make up two percent of the composition of a typical star. The implication of this was that most of the Universe was made of the light elements hydrogen and helium. This was truly are revolutionary idea that Cecilia Payne would eventually get full credit for this discovery
By 1925, Payne had already published six papers on the field of stellar atmospheres. She received her Ph.D. from Harvard and was awarded a staff position at the observatory. This same year she became the first recipient of a Ph.D. in astronomy from Radcliffe College, the sister school of Harvard.
It was in 1928 that Payne's thesis work on the composition of stars was finally published through Harvard. It was the first research of its kind and truly groundbreaking in the field of astronomy, though, as new ideas often do, it initially met with some resistance. The resistance waned as Payne discovered more evidence to support her theory through the analysis of star spectra to determine their composition and temperature.
Payne became a full American citizen, in 1931, shortly after the completion of her degree. In 1933 she met her future husband while visiting Germany. The following she married the well known Russian astrophysicists, Sergei Ilarionovich Gaposchkin, thus helping him gain American citizenship. She collaborated with him on much of her research throughout her career. It was with her husband that Cecilia Payne-Gaposchkin identified and measured many stars on photographic plates. Her compilation was small in comparison to that of Annie Jump Cannon, who had complied thousands of stars, in nine volumes by the time Payne-Gaposchkin arrived at Harvard. Regardless, their findings were published in a catalogue.
Both Annie Jump Cannon and Cecilia Payne-Gaposchkin were women involved in the study of stellar spectra. They were both pivotal in the role of women changing though they belonged to different mindsets in the world. Cannon belonged to the world in which men supervised, while women catalogued. Payne-Gaposchkin belonged to a time when women were just beginning to challenge gender roles and formulate theories. Their two world overlapped when they met at Harvard in 1929.
The American Astronomical Society recognized Payne-Gaposchkin's contribution to her field and awarded her the Annie J. Cannon Prize on 1934. Two years later she became a member of the American Philosophical Society. This was the beginning of a long line of awards, recognitions, and honorary doctorates she would receive. Her honorary doctorates came from Wilson College in 1942, Smith College in 1943, Western College in 1951, Colby College in 1958, and Women's Medical College of Philadelphia in 1961. She also received a masters of arts and doctorate in science from Cambridge. She was the first woman to receive the Henry Russell Prize from the American Astronomical Society in 1976. Radcliffe College gave her an award of Merit and the Franklin Institute presented her with the Rittenhouse Medal. Perhaps her greatest honor came in 1977 when the minor planet 1974 CA was officially renamed Payne-Gaposchkin in her honor.
During her period of time at Harvard, Payne-Gaoschkin actively participated in teaching. She was not formally awarded the title of professor until 1956, becoming the first woman to achieve this position at Harvard. She was also given the salary of her male counterparts, which was unprecedented at the time, and still rare to this day. She also became the chair of the whole astronomy department in the same year. Though this was a monumental step for women everywhere, it was long overdue. Her promotion began a long line of female professors at Harvard and other colleges across the United States.
Payne-Gaposchkin was known for her phenomenal memory, which made her a walking wealth of scientific knowledge. With the aid of her husband, she moved into the field of variable stars and did research on the composition and structure of the Milky Way Galaxy, The wealth of their studies came on from the two million star magnitudes which they calculated within Magellanic Clouds.
Cecilia Payne-Gaposchkin published over 150 scientific papers during her lifetime and several monographs. Most notable amongst these are Variable Stars, an astronomy reference book she wrote in collaboration with her husband and "The Stars of High Luminosity," an encyclopedia of astrophysics.
Cecilia and her husband had three children together. Edward was born in 1935, Katherine was born in 1937 and Peter was born in 1940. It was Katherine, now Katherine Haramundanis, who collected all of her mother's scientific research and writings and published them in 1984. The book is titled Cecilia Payne-Gaposchkin: An Autobiography and Other Recollections. The youngest of the children, Peter, became a noted physicist and programming analyst.
Though Cecilia Payne-Gaposchkin officially retired in 1966, she stayed active with the work of the observatory, since renamed the Smithsonian Astrophysical Observatory, and continued to teach some classes at Harvard until 1976. Her last scientific paper was published just before her death December 7, 1979 in Cambridge, Massachusetts.
She failed to receive the level of recognition due to her during her lifetime, and is largely left out of discussions on scientific contribution, but, Payne-Gaposchkin is beginning to get posthumous praise. In an article in Mercury magazine, famed astronomer Otto Struve states that her thesis, Stellar Atmospheres is undoubtedly the most brilliant astronomical Ph.D. thesis ever written.
Those who knew Cecilia, follow her work, or look up to her for any number of reasons, hope that one day her contributions to astronomy, physics, and astrophysics will be noted and celebrated. For this is what she deserves.
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