I study the element abundances in the solar neighborhood, or within 150pc of the Sun. I have put together the largest collection of stellar abundances, called the Hypatia Catalog, for 53 elements within +4,300 main sequence (FGK-type) stars as compiled from literature. Hypatia provides a wealth of chemical abundances and kinematic information which has implications for the evolution of our nearby galaxy, the formation of planetary systems, and astrobiology. The abundance measurements were combined from +100 different literature sources and the Hypatia Catalog will continue to expand as more determinations are made available. In order to address some of the issues discussed on the Research page, the catalog was "reduced" to ensure the most accurate analysis. The full, unadulterated dataset can be found with the original paper, through the Astronomical Journal (148, 54), or by clicking the top button on the right. The reduction of the data involved:
1) Ignoring those stars that were likely to originate from the thick disk;
2) Re-normalizing all of the abundances to the same solar scale;
3) Ignoring element determinations in stars where the measurements were not well agreed upon by the multiple groups who analyzed them -- to within error, or, when the spread for the element exceeded the error bar; and finally,
4) taking the median value in the case where different groups measured the same element in the same star. See Sections 3 & 4 for more details.
The reduced data set has been posted to Vizier (see also button to the right) in order to facilitate access and use. Please feel free to contact me if you have any questions or issues.
Through ASU and the NExSS research network, an independent database is currently being built to make the Hypatia Catalog as useful as possible to the community. The database will be free to the public and will include all of the current data, including individual literature sources, all elements and species, downloadable data, and an interactive plotting tool. The database should be complete around Fall 2017; please check back for more details.
I named my stellar abundance catalog after Hypatia, one of the first known female astronomers who was born between 350-375 AD in Alexandria and died around 415/6 AD (Deakin, 2007). Hypatia was an extraordinarily strong and independent woman, especially for the time. She was known to teach publicly from her house, covering astronomy, mathematics, and philosophy, and was highly regarded in Alexandria. Said Damascius, "In speech articulate and logical, in her actions prudent and public-spirited, and the rest of the city gave her suitable welcome and accorded her special respect." From Socrates: "She not infrequently appeared in public in the presence of the magistrates. Neither did she feel abashed in coming to an assembly of men. For all men on account of her extraordinary dignity and virtue admired her the more."
She worked closely with her father, Theon, on a number of editions and commentaries (seen as a sort of "student guide") on the works of Euclid's "Elements"and Ptolemy's "Almagest." After his death, she continued her work with her student Synesius of Cyrene, improving on the theories and designs they had established. While a number of books of hers have been destroyed or damaged throughout the years, much of what is known of the woman and her work are through letters corresponding with Synesius. From the letters we learned that Hypatia had a hand in designing the modern version of the armillary sphere and astrolabe (to predict the motion of nearby planets and stars) as well as the hydroscope or hydrometer (to measure the density of fluids).
A beautiful and unwed woman, Hypatia was a Neoplatonist who took an oath of chastity and, as a result, was not interested in the many suitors who admired her and her work. One story -- not for the faint of heart -- described an ocassion when a colleague or student fell in love with her and made his affections known. She responded to the man by showing him her menstrual "napkin," a clear indicator of her celibate lifestyle, saying, "It is this you love, young man, not beauty." According to Deakin, "…it makes perfect sense for a Neoplatonist, committed to transcending of the material world, to embrace a lifestyle that minimized her involvement with it."
Hypatia died in the midst of a religious power struggle in Alexandria. Around 412 AD, Cyril of Alexandria became archbishop, systematically targeting the Novatians and then the Jews for heresy against the Christian church. Orestes, the Christian civil governor, tried to mitigate the tensions by adopting a more tolerant and pluralistic standpoint. In doing this, he sought Hypatia's advice, making her a clear target for Cyril. In 415/6 AD, as Hypatia was on her way home, a group of Christian extremists dragged her from her carriage and into a church where they stripped her and beat her to death with tiles. They then tore her body apart and burnt the remains.
Hypatia was killed brutally, however, the manner of her death should not overshadow her determination and bold personality. What little is known about her research and her personality is still impressive. Deakin said it well: "By competence and by force of personality, she could command a crowd; her popular lectures and charismatic presence drew the multitudes. She held the ear of the legitimate authority and was heard with respect." Almost 1500 years later, these are traits still sought by scientists, especially female scientists, and they are something for which to strive as a professional. So it is with great reverence and appreciation that I invoke her name for my catalog of stellar abundances.
For a nice summary of Hypatia's life and achievements, please go here. And for more information, read "Hypatia of Alexandria: Mathematician and Martyr" by Michael A. B. Deakin (2007), which was quoted and used as a reference above. Additionally, Hypatia was a prominent character in the interesting time-travel science fiction novel "Weighing Shadows" by Lisa Goldstein. Also, a comic about Hypatia!