Beatriz Barbuy: In the wake of the first stars
Beatriz Barbuy, from São Paulo, is one of the most influential voices in Brazilian astrophysics and one of the most productive Brazilian scientists. Over the course of a career spanning more than three decades, the Full Professor at the University of São Paulo Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG-USP) has published about 210 articles in international journals, which have been cited in 8,000 articles by researchers. An expert in the chemical characterization of stellar populations, especially older, cooler stars, Beatriz has identified some of the oldest stars in the Milky Way, aged 12.5 billion years. From December, 1976 to January, 1982, she spent five years in France, where she was one of the first Brazilian women to study for a PhD in astrophysics. The time at the Paris Observatory, in the group led by Roger Cayrel, strongly influenced her career. “The doctorate there was more demanding, and I had to publish several articles,” recalls the researcher who has been a member of the French Academy of Sciences since 2006. “I had to learn to work.”
Articulate and successful, Barbuy has held important positions in Brazil and abroad. From 2003 to 2009, for example, she served as vice-president of the International Astronomical Union (IAU) and was particularly involved in the choice of 2009 as the International Year of Astronomy. In addition to conducting scientific research, she also led national initiatives that built instruments for the telescope consortia in which Brazil is a partner and has the right to observation time, such as the Southern Astrophysical Research Telescope (Soar), in Chile. The astrophysicist has always defended the idea that Brazil should be a member of one of three large telescope projects—with mirrors measuring from 30 to 40 meters—which are in the works for the start of the next decade and could take astronomy to a new level. In December 2010, the federal government chose to become a member of the European Southern Observatory (ESO), a consortium of 14 countries from the Old World with observatories in Chile, including the world’s largest radioastronomy observatory, the newly opened ALMA (see article on page 32). The ESO plans to build the largest land-based optical telescope, the European Extremely Large Telescope (E-ELT) in the early 2020s.
In this interview, the researcher talks about her personal trajectory, her research on stars and why she is in favor of Brazil’s participation in the ESO, which is now awaiting ratification by the Brazilian Congress. “Without the ESO, we have no future, because a community must have access to a large number of high-performance instruments in order to do quality research. Even the Americans don’t have infrastructure like this,” states Barbuy.
|Stellar and extragalactic astrophysics|
|University of São Paulo (undergraduate and master’s)|
|University of Paris VII / Paris Observatory (doctorate)|
|Lick Observatory (post-doctoral studies)|
|Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG/USP)|
What made you think of becoming a scientist?
I was 16. I read the book One Two Three… Infinity, by George Gamow. I had just started the humanities and social sciences concentration in secondary school, and decided to switch to the science concentration. I didn’t even tell my parents. I had to study a lot to catch up, since I had not done the first year of sciences. From then on, I never stopped working. There was another thing, too. When I was little, there was a plum tree in the yard of our house, on Rua Groenlândia, in the city of São Paulo. My branch was the highest one. My brothers had claimed the thicker, lower branches and I was left with the higher one. When I got home from school, I climbed up there and would gaze at the sky. I don’t know if it influenced me, but from the age of 6 to about 10, I would do this. I thought about studying psychology or languages. I read all of Freud’s works, which my mother had checked out of the Pontifical Catholic University (PUC) library, and I thought: “I’ll go crazy if I study just this.” I only understood some parts. But I thought I could study psychology through other means. I read a lot, and still do, and the subject interests me. I could also learn languages through other means, as indeed I did, although I am not an expert in any of them.
What did your parents do for a living?
They were both philosophy professors. My father at the University of São Paulo (USP) and my mother at PUC. They strongly influenced my studies. I never considered a non-intellectual career. I saw my father working all night, my mother teaching classes. Additionally, my older brother, who was in the science concentration, was much more fun than my friends in the humanities and social sciences concentration. That also influenced me. And I liked math, so I figured I was wasting my time in the humanities and social sciences concentration.
Did you think of becoming an astrophysicist shortly after you read the book?
The book spoke of islands in the Universe, of a telescope somewhere that allotted observation time. I asked someone how I could become an astrophysicist, and they told me I had to study physics. So, I went to USP with this goal.
Were there only a few women in your class?
Actually, there were quite a few. The problem was the dictatorship. Shortly after I started Mário Schenberg (one of the most famous Brazilian physicists) was imprisoned. A professor who was supposed to teach my class was imprisoned. A classmate disappeared. That sort of thing. This really had an effect on the impact of the course. The bathrooms had no locks on the stall doors. This was between 1969 and 1972, when the regime was at its worst. I worked in computer science for a while, then I went back to doing what I wanted to do. There was the USP Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG), which was still in the Água Funda neighborhood, and there was an astronomy group there. In the last year of my undergraduate degree in physics, I went there to talk to them, but the astronomy group was just starting. I did my master’s at USP, but things improved when I went to do my doctorate at the Paris Observatory in 1976. My career was just starting, and it was important for me to go to France. I had a scholarship from the National Council for Scientific and Technological Development (CNPq), as well as a scholarship from the French Consulate. Although they were small, the two were enough so I could study.
Is your last name, Barbuy, French?
It is, but my great-grandfather immigrated to Brazil from Italy. In Italy, they spell Barbuy with an I, rather than a Y. Supposedly, the Barbuy family went to Italy with Napoleon, but no one knows for sure. My sister, who works at the Paulista Museum, found a document from 1758 from some Barbuy with a dieresis [two dots] over the y, from the north of France. He was a Catholic priest.
You went to work with Roger Cayrel at the Paris Observatory?
The contact with Roger and Giusa Cayrel was made through Licio da Silva, at the National Observatory. They were leaving for Hawaii, where they planned to work on the construction of the Canada-France-Hawaii telescope. Monique Spite, who was returning from a long period in Chile, agreed to be my advisor. The entire group was exceptional, so much so that they continue producing even today.
What was the subject of your research?
I wanted to study chemical evolution and make observations. I stayed in France for 5 years. The doctorate there was more demanding, and I had to publish several articles. It was great because the group had several different personalities. Monique was very practical. She reduced complicated things to a single instruction, and Roger was terribly intelligent—it took me about 10 years to understand things at his level. The group was large, with many people observing the stars. I had to learn to work. Here, students do not always show up at the university every day. There, everyone worked every day for who knows how many hours, and you could tell you were in one of the more serious professions. Astrophysics is interesting. There is theory—you have to read a lot—but there is also data. When you get tired of theory, you work with the data. This variety of tasks allows you to put in long hours.
What was the subject of your first article?
It was on an old star in the Milky Way’s halo called HD 76932. I calculated its abundance of heavy elements and its temperature with stellar spectroscopy. In my area, heavy elements are those heavier than iron, such as cerium and neodymium. The interesting thing about having an article published is that you learn to write. It was published in Astronomy and Astrophysics, a European journal, that today is edited jointly with Brazil, Chile and Argentina.
Are you in the same area of research today?
Yes, the same. I’ve gained expertise, and I believe one must have expertise to be a good researcher. Some people don’t have the expertise; they take some images and then start looking at everything. It takes many years to become good. Since I worked in a very good group, this was what drove my research.
Where did you get the idea to study the evolution of the stars in the Milky Way?
It was probably during my Master’s that I became interested in chemical evolution. Studying cool, low-mass stars, was a suggestion from Roger, the father of the group. Martin Schwarzschild, who was well known in the field of stellar evolution, was in Paris during the 1950s and told Roger that if he wanted to study galaxy formation and evolution, he had to study low-mass stars. This advice made all the difference. These stars are very old, and were formed when the galaxy emerged. So when we observe them, we are seeing the beginnings of the galaxy. The highest-mass stars explode quickly. Those we observe today are young. In low-mass stars we see what existed when the galaxy formed. In general, the chemical elements found on the surface of these stars reflect the original material of the galaxy, such as its low iron concentration. Stars with low metal concentrations are the first generation of low-mass stars. But they are not the first generation of stars in the galaxy. The first generation was massive. Why were the first stars massive? Because they had no metals to cool them. Probably the first were all massive. Cooling is important for condensation, which allows gas clouds to fragment. This led to smaller clouds creating smaller stars.
What is a cool star?
Stars with temperatures below 7,000 degrees Kelvin, which are the majority.
What happens in these cooler stars?
They are converting hydrogen into helium in the core if they are dwarf, or in their outer layers if not. One of Schenberg’s best-known contributions concerns dwarf stars, like the Sun When it has burned 10% of its hydrogen into helium, the Sun will expand and become a giant star.
What is the age of these stars, in general?
The old, low-mass stars in the halo are about 13 billion years old. One goal is to find out which are the first high mass stars by using the giant ground-based telescopes that are being planned and the future James Webb Space Telescope.
Have you always worked with stars in the Milky Way?
I also worked with stars from nearby galaxies, called the local group, such as the Magellanic Clouds. The stars of more distant galaxies are weaker, and cannot be observed. We might be able to see a cluster of stars, which can be seen from far away due to their greater brightness. But high-resolution spectroscopy does not yet allow this. This is one of the things we want to do with the giant telescopes. There are also some articles on stellar populations in elliptical galaxies, which are studied using their integrated light. Three of my students did their theses on this topic.
Where exactly are the Milky Way stars that you study?
First, I studied the stars in the halo [the spherical region surrounding the galaxy, containing rarefied gas and very old stars], which are easier to see. In the 1980s, astrophysicists began discussing the first generation of stars, which would be expected to be metal-poor. My dissertation was on metal-poor halo stars, but over the years I became more interested in the center of the galaxy. Currently, this is my main interest. Today there is some discussion as to whether or not the first stars formed in the center of the galaxy, where this process would have been more intense. The oldest ones should be there in the center. So, in recent years I have studied the bulge of the galaxy, but also continued studying the halo.
What interested you in this particular subject?
I have always been interested in the chemical evolution of our galaxy. It is an area that combines atomic physics and chemistry, and one in which you have to know the characteristics of atomic or molecular transitions. My specialty is molecular bands, an area in which few people are working. It requires knowledge of nucleosynthesis (the process of creating new atomic nuclei from existing nuclei), how elements are formed, their chemical evolution, and the formation of stars. In sum, it involves many things.
In our galaxy, what do you see in terms of chemical evolution?
The bulge of our galaxy is very similar to the bulge of other spiral and elliptical galaxies. They all have those strong bands of magnesium and iron, in different proportions. Or in other words, their stellar populations are similar.
Wasn’t that expected?
Yes, it is very uniform. The galaxy formation process was probably very similar. There are differences in the proportions of the chemical elements. There may be more alpha elements [whose more abundant isotopes are multiples of four, the mass of the helium nucleus], such as oxygen (16) and calcium (20). Alpha elements indicate if rapid enrichment occurred in massive stars or not. That’s what I do. I look for these elements, evidence that supernovae enriched the gas from which that star formed. During my doctorate I sought to discover the first generation of stars, those first supernovae. This is the search for origins. That is why it’s interesting.
You are one of the authors of a 2001 study that found what was then considered the oldest star, CS 31082-001. What was that like?
It was the first time that uranium was detected in a star outside the solar system. It is a heavy, radioactive chemical element. Its decay allows us to calculate the age of the star directly, with no further data needed. The paper was published in the journal Nature. According to initial calculations, the star was 14 billion years old. Later, a group in Sweden measured the atomic transitions of uranium and we recalculated the age of the star to be 12.5 billion years old, with a margin of error of plus or minus 2 billion years.
Is this star from the first generation of stars?
Perhaps. In some of these metal-poor stars, there is evidence that their contents are the result of a single supernova. It would therefore be from a second generation. In a paper written with Cristina Chiappini (a Brazilian astrophysicist at the Leibniz-Institut für Astrophysik Potsdam), which was published in Nature in 2011, we showed that the abundances of metals in a stellar cluster in the bulge of the NGC 6522 galaxy could be the result of high-spin, high-mass supernovae.
What is a high-spin supernova?
They are stars that spin at a speed of 400 km/s. Hot stars spin quickly, in general. However, no one had calculated the nucleosynthesis of these stars, and this group in Europe did. Now they are at the point where they can make predictions. It is a collaboration between me, as an observer, this group of theorists, and Cristina, who creates chemical evolution models.
Which of your articles has had the greatest impact?
One of my most important articles was published in 1988. My dissertation had been on the presence of carbon, nitrogen and oxygen in cool stars. At the time, I requested ESO observation time and I obtained seven great nights of observation. I showed that the stars in the halo [of the Milky Way] had an excess of oxygen. That was a constant. And what does it mean? It means that the halo was rapidly enriched by type 2 supernovae. Oxygen is only produced in massive stars, those that will become type 2 supernovae. It was the first clear evidence of excess alpha elements in the halo. The same thing happens in the nuclei of galaxies, in their bulges. This was the work that I became known for. In 1992, I published an article on the occurrence of high magnesium concentration in galaxies. After that, many of the things I did were along those lines. Another important project was on the grid of stellar spectra. Atomic and molecular bands are needed for their calculation. I worked on this subject with my students for 20 years. The spectrum of a cluster of stars could be used to determine the composition of a population of stars in a galaxy, for example. A galaxy has all sorts of stars. Thus, it is necessary to take a weighted sum, based on the brightness of these stars. We calculated the spectra of stars with different gravities, metallicities and temperatures, from giants to dwarfs. So, in a doctoral dissertation, a student, Paula Coelho, put this all together and we published an article in conjunction with three other former students who had worked on it. This work has been widely cited. I think I am currently the most cited female astrophysicist in Brazil, with figures similar to those of Eduardo Bica [of the Federal University of Rio Grande do Sul] and Luiz Alberto Nicolaci da Costa [of the National Observatory]. I have 8,500 citations according to the Nasa/ADS database, and 7,500 according to the ISI.
What is your current area of research?
Metal-poor clusters in the bulge of the Milky Way, which are thought to be the oldest in the galaxy. One of them has two distinct populations of stars. This is a current topic in the literature. It was always thought that clusters were composed of a single population.
Returning to your personal history, why did you go back to Brazil?
I went back, principally, because I had signed an agreement with the CNPq saying that I would return and remain in Brazil double the time I was abroad. I stayed in France for 5 years. So I had to spend 10 here. I do not like to make a commitment and not fulfill it. This was the most important reason. Secondly, I came back because you will always be a foreigner abroad. I spent the first three years in Paris wanting to go home. I only enjoyed being there more the last two years. I always wanted to go back. I think that Brazilians, more than people of other nationalities, have this desire to go home. And finally, there was the matter of the climate and family, of course.
What did you find when you returned to Brazil?
When I returned, what did I have? A desk, which, incidentally, was this one, only it was at IAG’s old address. That was it. I had no computer, nothing. And, even worse, there was that 1980s law which did not allow me to purchase a computer. That law killed certain areas of engineering, and the effects are still being felt. It was the worst thing that happened to Brazil. Even today we do not have a national computer. In the 1980s, I went to France every year and stayed there for months doing calculations because here at USP the Electronic Computer Center [ECC] had no plotter [a type of high definition printer, used to produce vector graphics]. The plotter was broken 11 months out of every year. I worked with spectra, and I had to see the spectra. I began to request time at the ESO and also in Hawaiian telescopes and was successful. Back then it was easier to get time, but I had to stay there to manipulate and reduce the data. We had nothing here. I spent months abroad. Usually it was the Paris Observatory that paid for my trips. I owe a lot to France. Here I rarely obtained financing. They always denied my requests. They thought I went abroad too often, that it was not necessary. They didn’t understand that I had to perform calculations. I spent 12 hours a day at the computer, calculating, in Paris. So the 1980s were terrible, they really delayed my career. I worked like a prisoner. I would go to the ECC up to three times a day. And remember that I worked in the Água Funda building. I had a lot of energy, to go back and forth. I was wasting my time. If I had stayed in Europe, it would have been better. In the 1990s we fought to get a good computer and FAPESP provided funds for a Vax. Then the situation changed. But this only happened eight years after my return.
Despite all these difficulties, your career was already well established in the 1990s. In 1992, for example, you were already president of the Brazilian Astronomical Society (SAB).
That’s true. Despite the difficulties, I managed to work. Being a woman did not hold me back. I always discussed this issue [of discrimination against women] with Mayana Zatz [geneticist at the USP Biosciences Institute] and Belita Koiller [physicist at the Federal University of Rio de Janeiro (UFRJ)] in a Brazilian Academy Sciences [ABC] discussion group on the subject. In Brazil, if you work and produce, nobody puts obstacles in your way. If we do twice as much as others do, why would they hold us back?
But isn’t it true that a woman has to do more than a man to be recognized as a researcher?
Yes. I think women have to do more. Some of it is machismo. But, if you do more, there is no problem. Brazil is not very rigid on this issue. But, if you do a little less… If you are serious and work hard, nobody puts obstacles in your way
Did you experience some prejudice for being foreign and a woman in France?
It made no difference at all, I was discriminated against less there than I was here. On the one hand, I was fortunate to have been able to go to France. In Anglo-Saxon countries, in the United States, the situation is different. The French, in particular, have warm feelings for Brazil, and all that counts. On the other hand, I went to Paris while there was a dictatorship in Brazil, and I was not treated very well. I arrived in France and people said: “I heard there are 36 generals in Brazil.” There, saying 36 is like saying 1 million in Brazil, it means “a lot.” And I replied: “Only 36?”. Their just associating Brazil with Pelé, coffee and samba irritated me. But today, thanks to Cardoso and Lula, they have much more respect for Brazil. On second thought, I think I was a little mistreated, yes. Everyone was. You can’t compare it to the last 20 years, when things improved.
How did you get to be IAU Vice President from 2003 to 2009?
I had already been president of Commission 29, on Stellar Spectra, and Division 4, on Stars. It was a natural progression. Anyway, it was acknowledgement; no one in Brazil had risen so far. There is also the fact that being Brazilian and a woman helps. This makes you more visible. So, sometimes it helps rather than hinders at the international level. I had a large part in the most important thing the IAU has done, the International Year of Astronomy in 2009. Brazil, in fact, played an important role. And do you know why? Because large countries do not want to hear about this year and that year. Earlier, there had been the International Year of Physics, and only a few countries, including Brazil and Portugal, made an official request in favor of this initiative. Brazil is one of the seven countries that recognized the International Year of Astronomy. The support of the Ministry of Foreign Affairs was great. The other countries did not support it because they did not want the distraction of special years. But this type of initiative is important. I went to events abroad, I did everything I could, we promoted it well and it was quite important. Another initiative in which I participated was the IAU General Assembly in Rio de Janeiro in 2009.
What was the most important point in your career?
I think it was when I joined the French Academy of Sciences. I went to France repeatedly over a period of 30 years, working hard, staying in budget hotels. I began my doctorate there in 1976, and I was accepted by the Academy in 2006. It was a very important acknowledgment. There are only 150 foreign members in the Academy, many of them Nobel Prize winners. It appears that many people voted for me.
Was your election to the Academy unexpected?
I never imagined it would happen. They did everything without telling me. This is the highest honor I have received. In 2008, I received the Trieste Award, from The Academy of Sciences for the Developing World (TWAS), which was also very important. I also received the L’Oréal-UNESCO Award For Women in Science in 2009. The latter elevated me to a higher level, in some respects, due to the extensive media promotion. For example, last month there were panels along the Champs Elysées with photos of the last 15 years of award winners, including the five Brazilians.
At the Millennium Institute, the objective was to begin to develop Brazil’s know-how in manufacturing instruments for the international telescopes in which Brazil is a partner. How would you rate that experiment?
We wanted to make instruments for the Gemini and Soar telescopes [both located in Chile, and for which Brazil has observation time]. Ultimately, the group that builds an instrument is the one that knows it best and can best take advantage of it. If you want to observe something, it’s best to build an instrument for this purpose. That’s what they do there. The goal of the Millennium Institute was to evolve from an initial situation, in terms of instrumentation, to a situation with infrastructure and knowledge to build instruments. However, it was tremendous work to make the Sifs spectrograph together with the team from the National Astrophysics Laboratory (LNA). We are learning, slowly.
What problems came up during this process?
We don’t even know how to negotiate with companies. One company that wanted us to double its payment and wanted to block the construction of an instrument. They do what they want. We think that everyone is a scientist and interested in research, but that’s not how it is. We have to work differently. What do we want? Innovation. Astronomy develops cutting-edge technology. Sifs generated two patents for new materials, which are now being used in another instrument. Sifs has optical fibers that cannot have any play. They must remain firmly in place. The instrument has a lens up front and the fibers have to be securely anchored. Everyone secures fibers with a hard material. But Antônio César de Oliveira, who studied in São Carlos, created a material—a flexible mixture— that is easy to bore precisely. This is one of the patents. Sifs therefore allowed us to become experts in optical fibers.
What are the other two instruments that are being developed?
The Steles high resolution spectrograph, for Soar, is being developed by Bruno Castilho and should be ready by the end of the year. And there is the BTFi [an adjustable imager for Soar]. All three instruments are funded by FAPESP. This support is important.
How did Brazil become involved with ESO?
Many Brazilians have been making observations at ESO their entire lives. Between 2006 and 2011, for example, Brazilians produced 77 articles with Gemini, 25 with Soar, and over 200 using the ESO, where there are all sorts of observation instruments. That is how the involvement came to be. Within the National Institute of Science and Technology for Astrophysics (INCT-A), I proposed that we take part in one of the large telescope projects during the planning stages. I contacted the three major projects, the Giant Magellan Telescope (GMT), the Thirty Meter Telescope (TMT) and the ESO. The TMT wanted $100 million to add Brazil. The GMT said it would not commit to using our industry, which for us was an important point, so we did not follow up. ESO asked for twice as much as the other projects to accept us as a member. On the Special Astronomy Commission, created by the Ministry of Science and Technology, we discussed the fact that, if we joined the GMT or the TMT, our community would have to wait 10 years for the telescopes to be ready, and only then could we start to produce research. Becoming an ESO partner would allow us to do everything immediately, because they would already make their telescopes available.
Was the process of joining the ESO discussed among astrophysicists?
It was. On March 29, 2010, I called all of the principal researchers in Brazil for a meeting, and 80 came. At the meeting, the vast majority voted in favor of joining the ESO. Then, the Brazilian Astronomy Association consulted all researchers with doctorates through the Special Astronomy Commission and, again, the vast majority were in favor. In the National Astronomy Plan, in which this issue was a priority, the question was also discussed extensively by a large number of participants. The same occurred during plenary talks at the SAB conference in 2010. Without the ESO, we will have no future Even the Americans don’t have infrastructure like the ESO has. We asked the then Minister of Science and Technology, Sergio Rezende, what our limit was. He said to choose the best project and he would see how we could make it work. And that is what we did. The amounts were negotiated by a commission put together by the Ministry of Science and Technology, of which then SAB president Eduardo Janot Pacheco, then LNA director Albert Bruch and Ademar Cruz, of the Ministry of Foreign Affairs, were members. We saved €100 million in the negotiations with the ESO.
Brazil is expected to pay just over €130 million in 10 installments to enter the ESO, plus an annual fee.
Some say that this figure is high for a small community of astrophysicists, like Brazil.
It is not a small community. There are 700 astrophysicists, 330 with teaching contracts and more as post-docs, plus students.
In the model used by some telescopes, a partner who pays 10% of the project budget is granted 10% of the observation time. ESO does not work that way. Won’t we run the risk of paying a lot of money and not obtaining observation time?
Under the agreement with the ESO, the value of our contribution will increase gradually up to a ceiling and, to adapt, we will initially have 3% of the observation time. The central issue is that, if we are not members of the ESO, in many cases we would not be able to be the principal investigators of a project, we would not be the first author of an article. We need to learn to compete, and for that you need to do cutting-edge research, as part of the international community.
Some time ago, you were involved in an initiative to relaunch the science kits that were around in the 1970s. What is the status of this project?
The kits will be introduced now. In the beginning, there will be five kits: one for chemistry, one for optics, one for genetics, one for math and one galileoscope. The engine behind this is Herch Moysés Nussenzveig [a physicist at UFRJ]. The other members of the group are also of the highest level: Vanderlei Bagnato (USP São Carlos Institute of Physics), Mayana Zatz and Eliana Dessen (USP Institute of Biology), Henrique Toma (USP Institute of Chemistry), Eduardo Colli (USP Institute of Mathematics and Statistics), Carlos Henrique de Brito Cruz (Unicamp Institute of Physics and scientific director of FAPESP). The goal is to motivate children and adolescents to learn science through the experiments proposed in the kits. We had never seen a kit as good as the optics kit. And there are already groups interested overseas. The Coordinating Agency for the Improvement of Higher Education Personnel (Capes) liked the project and provided initial funding to carry out some tests with school children. One thousand kits of each type, five thousand total, will be tested this semester. The next steps will be to improve the material, depending on the outcome of the tests, and to distribute more kits. The development of 20 other kits is already being planned.