Uncovering Star Composition with Catherine Deibel
When you look in the mirror, do you see a star? Of course you do! Your body is composed
of the elements of stars. We met with Dr. Catherine Deibel, Assistant Professor of
the Department of Physics and Astronomy, to learn about her research in experimental nuclear astrophysics, the importance
of basic research in discovery, and explain how we are all made from the ashes of
stars. (Transcript below.) Photo courtesy of NASA.
Listen to the full episode below, and subscribe to LSU Experimental on Apple Podcasts, Google Play, Stitcher, Spotify, TuneIn or anywhere you get your podcasts.
LSU Experimental is a podcast series that shares the research and the “behind the scenes” stories of LSU faculty, student, and alumni investigators across the disciplines. Listen and learn about the exciting topics of study and the individuals posing the questions. Each episode is recorded and produced in CxC Studio 151 on the campus of Louisiana State University, and is supported by LSU Communication across the Curriculum and LSU College of Science. LSU Experimental is hosted by Dr. Becky Carmichael and edited by Kyle Sirovy.
Transcript
Becky Carmichael
[0:01] This is Experimental, where we explore exciting research occurring at Louisiana State University and learn about the individuals posing the questions. I'm Becky Carmichael and today Dr. Catherine Deibel, from the Department of Physics joins us to share her research in experimental nuclear astrophysics, and explain how we are all made from the ashes of stars.
Catherine Deibel
[0:23] So when people ask me what I do, I like to start just at the beginning. And at the beginning, there was the big bang about 13.7 billion years ago or so. And after the Big Bang sort of settled down, maybe three minutes after the beginning of the universe or so, the only things that came out of that in terms of the elements that you might see on the periodic table were the first three elements: hydrogen, helium, and a very small amount of lithium. But obviously, we're sitting here today breathing oxygen, there's calcium in our bones, iron in our blood. So the question you might be asking yourself is where did everything else that's in this periodic table come from? And the answer is that all of those different elements, everything heavier than lithium was synthesized as stars burn and explode. And so, as a star explodes, it emits all of the stuff that was created in the stellar explosion or in the burning leading up to that explosion, into the interstellar medium that eventually condenses to form solar systems, planets, and eventually us. So what I do is I essentially try to study, in the laboratory, those reactions that happen when two nuclei react, to create heavier elements and figure out what the story is behind all of those elements being synthesized in stars.
Becky Carmichael
[1:45] So Dr. Deibel, thank you so much for joining us today. I wanted to hear a little bit about you know who you are, where, well you know, a little bit about what you do, and maybe like, a little bit about your past coming and being a faculty member here at Louisiana State University.
Catherine Deibel
[2:01] Sure. So I am an East Coast girl from the beginning and lived outside of DC and Maryland, went to school in New England for both undergrad and graduate school. And after receiving my Ph.D., I went on to be a postdoctoral researcher at a national laboratory run by the Department of Energy. It's called Argonne National Laboratory. It's one of the labs that came out of the bomb effort, but there's no bomb stuff there anymore. [laughter] Okay. And then after about three and a half years there, I joined the faculty at LSU and I've been here for about five and a half years now.
Becky Carmichael
[2:40] And so here at LSU you are you continuing on any other research that you did at with Argonne?
Catherine Deibel
[2:46] Yeah, so a lot of my research program is still there. I sort of started a program to measure a series of nuclear reactions that are important for one specific type of stellar explosion while I was there, and I've kind of continued the trajectory of that- of that program, as well as adding on kind of new types of things that I'm interested in, both at Argonne and other laboratories around the country and the world.
Becky Carmichael
[3:12] And so you mentioned you're looking at one particular stellular- stellular?
Catherine Deibel
[3:16] Stellar...
Becky Carmichael
[3:17] Stellar? Man that was a great kind of.. let me see if I can pronounce that again. Stellar... explosion. Can you tell me a little bit about what, what's that specifically?
Catherine Deibel
[3:29] Sure. So the types of explosions I'm in happen on binary systems. So those are two stars that are orbiting each other. One star will be very similar to our sun, which is mostly made of hydrogen and some helium. And the other star will be a very compact star, which means it's very, very dense. So there's sort of two types of systems: one where that's a white dwarf star, and one that's a neutron star. And just to give you a sense of things, a neutron star is like if you took the entire earth and you smushed it up and put it in Tiger Stadium, that's the sort of density we're talking about. And because these stars are so dense, they basically suck material off of their companion, like the sun like star that we have rotating around it. And that causes heat and pressure and density all to build up on the surface of this smaller, denser star. And eventually, you have what we call thermonuclear runaway. It's almost like a bomb going off across the surface of the star, you have a rapid series of nuclear reactions that produce a whole bunch of elements up to you know, some mass depending on the type of explosion, and some of (the) times that will get ejected into the universe, or sometimes it will get sucked back onto the surface of the star and have an effect for the next explosion because these sort of are iterative events, they happen over and over again.
Becky Carmichael
[4:58] So can you sample some of these different elements that may be in particular locations. Well, I guess you couldn't do it in space. But well, when- how do you, how do you measure those elements then?
Catherine Deibel
[5:08] So there's sort of- the good thing about nuclear astrophysics or one of the interesting things, I think, is that it really is a multidisciplinary type of field. So there's sort of three main components. One is the kind of astrophysics of it and the observational component. So people who are actual astrophysicist, not like me, but, do do more observational kinds of things. They can actually look up at some of these stars and tell from looking at these observations, what types of elements are being produced. There's also in addition to the observations from satellites and telescopes, you can also look at meteors. So every now and again when you have some material that's blown off of a star, little grains of that will be encapsulated in meteors and fall to earth. And you can actually chip those out of the little meteors and study what the. the different elements are in those and get a little snapshot, if you will, of what's in a star. And so those sort of inform what we think might be created in different types of stellar environments and explosions. And then of course, there's the theoretical side where you try to model these stellar environments and explosions. But to go into those models, you need to understand the nuclear reactions that drive the burning and the explosions. And those can be sort of theoretically modeled to some extent, but you really need experimental data to know what you're doing. And so that's where we come in and we do those experiments that measure their the rates of different nuclear reactions and that kind of information.
Becky Carmichael
[6:50] And how is your research, how is it applied to other aspects? So, daily life, why should someone outside of the realm of physics care about your experimental research?
Catherine Deibel
[7:02] Well, there's the general argument, which I firmly believe in, that basic research is in and of itself very beneficial. You never know where that next discovery is going to come from that leads you to the transistor or to, you know, the components of your cell phone or what have you. I mean, all of the technology we use today at some level came out of basic research without knowing what the applications would be. So there's of course, that argument in general, but also what we do, does have some applications to things like national security, and stockpiles stewardship and that kind of thing, and maybe not so much directly with the- some of the specific reactions that I'm studying, but there's certainly a lot of overlap with the field and the nuclear physics that we study and those kinds of applications as well as of course, more broadly nuclear power and that kind of thing.
Becky Carmichael
[7:54] Kind of from your star, what really narrowed you into say "I want to go into Physics." what was that moment?
Catherine Deibel
[8:02] So I always love science even as a little guy. I was, you know, the kid who asked for a microscope for Christmas and all that kind of stuff. And, you know, I took all the science classes that were offered in middle school and high school and that kind of thing. And then eventually, in 11th grade, I think, I took my first physics class and I just really liked that it was kind of getting at the basic questions that were the underlying, you know, reasons why everything worked. It wasn't trying to describe the phenomenon necessarily, but really trying to understand at the most basic level, why the world looks the way it does, and I, I found that extremely appealing. And so I went off to college and figured I would continue on with physics and maybe try a bunch of different things and see if anything, grabbed me more and nothing ever did. So that's where I ended up.
Becky Carmichael
[8:55] I was gonna say that was, I always think that you know, you figure out that that niche and then try other things but if you keep coming back, you know you're in the right path.
Catherine Deibel
[9:04] Yeah, I agree.
Becky Carmichael
[9:06] So you've mentioned a couple of times, you know, your work with Argonne. And you've also mentioned some other groups. Tell me a little bit about the collaborations that you're involved with and how that influences both the questions that you can ask and maybe the places that you can do your research.
Catherine Deibel
[9:25] Right. So so fundamentally, I mean, how one does an experiment in my field is you basically have to accelerate a beam of particles, some specific nucleus that you're interested in. So you give it a lot of kinetic energy, a lot of speed. And then you essentially collide it with a different type of particle and see what reacts and what the products are of that reaction. So you kind of need two things to do this. You need a particle accelerator. Nothing too crazy like what you would see at FERMI lab or the Large Hadron Collider over in Europe, but something a little much lower in energy. And then you also need detectors to detect the products of the reaction that happens when you collide these nuclei together. And so the collaborations that I'm involved with sort of get at both of those aspects. One is just that you need to go to the labs where it's possible to do the- study the reactions you want to do. And that is sort of- that in itself can be a challenge, especially for the type of research I do because as you can maybe Imagine you have these extreme stellar environments. And the reactions that happen in those environments don't always happen on stable nuclei, that is nuclei that live forever, but rather happen on unstable or radioactive nuclei and those aren't just laying around waiting for somebody to accelerate them. You need to produce them in the laboratory, and then accelerate them and so we're at a really exciting time in the field because new and improved accelerators are becoming available and currently being built even that are going to all of a sudden be able to give us all of these accelerated beams of elements that we were never able to access before that are, that are radioactive. And then that brings all kinds of challenges with regards to detectors and that kind of thing. But anyway, to answer your question, finally. So there's a couple of labs that are doing sort of these new and exciting things. And one is the facility for isotope beams, which is actually currently under construction in Michigan State University. It's a $700 million facility that is going to turn on in, I believe either 2020 or 2022, depending on how things go. I would have to check on that date to be 100% right. And, and so we're doing a lot of work, developing methods to use these new beams that they'll be able to produce in the most efficient and unique and exciting ways to study some of these reactions for the first time. And we also have a huge collaboration going with Florida State University, they have a much smaller accelerator at their university. And we just moved a 36 ton magnet from Yale University, who used to have an accelerator which shut down, down to Florida and we're installing it right now because to in order to measure these reaction products, most of the reaction products, or a lot of them will be, you know, particles that actually have a charge, like a proton has a charge of plus one, and moving charges bend in magnetic fields, according to their mass and their charge and their energy. And so oftentimes, we will use big spectrographs and big magnets to sort of separate out different products from the reaction that we're trying to study and be able to detect them more easily. So we're in the process of installing this new, well, old but new at this laboratory, spectrograph.
Becky Carmichael
[13:03] I can imagine there's some logistical kind of complications with moving a magnet of that size.
Catherine Deibel
[13:09] Yeah, I did not, you know, attach it to my Prius and drive it down the east coast [laughter]. So there's certainly a lot of engineering aspects to doing something like this, especially in Florida, which is a bit swampy. So, we sort of hired professionals to do or disassemble the magnet at Yale and then three flatbed trucks were used to ship it down to Florida. And then once we were there, there had to be all kinds of things like soil samples to make sure that the Earth was appropriate and then even so, it would just fall through the floor probably so there were piles that were driven down 20 or 40 feet into the earth and a concrete sort of pedestal that was poured just a couple of months ago. And now we're finally at the place where we're about to install the magnet.
Becky Carmichael
[14:08] So probably These aren't things that you thought you'd have to be doing, kind of, at the onset of this, or your career?
Catherine Deibel
[14:14
Yeah, [laughter] and to be fair, I'm not actually doing any of these things. I'm, you know, sort of helping the planning process, but we hire professionals to do those kind of things.
Becky Carmichael
[14:29] So kind of taking, kind of, a step back and thinking about, you know, what you thought you would be doing, is there, you know, when you first started on this career path, and then kind of reflecting back on what you know now, is there something you would tell your younger self, based on your knowledge?
Catherine Deibel
[14:47] I would probably tell my younger self not to worry so much and that, you know, there's a lot of things that are sort of unexpected that you know, you sort of have this vision of a scientist or physicist, you know, alone toiling away in a laboratory and, you know, very sort of isolated and the sort of most surprising things that I found that I didn't expect going into this career path is that there's a lot of interpersonal relationships, there's a lot of collaboration. There's also a lot of travel, I travel a ton to different conferences and experiments and that kind of thing, which is really I love traveling. So that's really sort of exciting. And I think I was a little worried that I would be a bit isolated when I started down this road. And that's not the case at all. I mean, I'm working with people 100% of the time and have lots of- developed lots of interpersonal relationships and that kind of thing, which is really nice.
Becky Carmichael
[15:51] And that also probably helps for support too. And kind of, you know for your own mental sake, yeah, you're getting into the, you know, whatever science you're getting into, there's, you know those questions that you're struggling with, those answers you're trying to find and, or even if you're working with some kind of software, and it's not cooperating or moving a 36 six ton magnet. Yeah.
Catherine Deibel
[16:14] Yeah, it's true. And once you specialize, and I think this is true, and probably most sort of sub-sub-sub-fields in physics or any other scientists, it becomes sort of a nice, smaller community and you get to know most of the people that are sort of doing similar things to what you're doing are in that community. And it's, it's sort of, it's a nice little I don't know I keep saying community. [laughter]
Becky Carmichael
[16:46] This is a - do you have or have you met that one physicist or that one scientist that you were most excited to meet when you first started out, or.?
Catherine Deibel
[16:58] I don’t know if I had any sort of like, idealistic sort of feelings about anybody in my field, I do remember that the first talk I ever gave, as a grad student, I think it was in my first or second year in grad school at a .. we have these things called summer schools where you go for a week or two, and it's sort of all day every day lectures by different people who have different specialties in you know, your field, so in nuclear astrophysics for this case, and I gave my little talk, you know, 15 minute schpiel about what I was doing. And the first person to raise their hand and ask me a question was the guy who wrote the textbook on the field. And fortunately, I had a backup slide that was exactly the answer to the question he was asking. So I always tell my students, you know, add backup slides to your talk because you never know what will happen. So that was a little intimidating, but um, but everybody's been you know, like, very nice, very supportive, there's always going to be some egos and that kind of thing in any field but I think in our community, it's- it's a great group of people for the most part, and they're very supportive.
Becky Carmichael
[17:30] What do you.. what do you see yourself doing next?
Catherine Deibel
[18:16] Well, I have a lot of projects that I'm involved in now. So taking them to their fruition is of course, my immediate goal, like this magnet that I talked about that we're installing, and a couple of experiments that are sort of on the books at different laboratories, kind of waiting to be run. A lot of, sort of, my future program will depend on what's available from these new facilities that are being built and what you know, we can really, where we can push the boundaries and, you know, what will be necessary to do those things.
Becky Carmichael
[18:47] I want to kind of go back at kind of that, that idea of, you know, what we think of as the typical scientists. So what are some things either that you encourage your students to do or that you try to model to break that, that idea that 1. What a scientist looks like, or- or and or, I should say, that physics is hard.
Catherine Deibel
[19:11] Yeah, I think I mean, I think that the whole physics being hard thing is, well for one thing I don't know if misconception is the right word, but lots of stuff is hard, right? I mean, I find things in the arts and humanities extremely difficult. You know, everybody's mind works differently. And I don't, you know, I think that everybody can benefit from being well rounded intellectually, and that includes, you know, literature, science, music, or, you know, philosophy, all of that kind of stuff is beneficial to everybody. I think that the problem with physics is that there's this misconception that it is harder than everything else, as opposed to just being different than a lot of other things. A lot of it is just, you know, logic and just kind of thinking about the way the world works in a logical way. And, you know, figuring out why misconceptions about, you know, the reason why you feel a force when a car is turning feels one way, but it's actually directed another way and reframing that in terms of, you know, the laws of physics and kind of logically stepping from there. So I think that's, that's a big part of it, is just kind of getting rid of your misconceptions about what is hard, what is not hard and letting yourself be open to, to knowledge. So yeah, I would say that that's kind of the main thing with regards to you know, how people view physics, in terms of how people view physicist, there's definitely the kind of image of old crazy white man (Laughter) toiling away by the blackboard or in the laboratory, and that is, at least in my experience, certainly not the case. In most cases I think that, you know, it's a shame that pop culture and that kind of thing doesn't do a lot to dispel those stereotypes of white males being the majority in physics and it's true that they are the majority, but there's certainly a very strong, you know, minority that's becoming less and less of a minority that, you know, doesn't fit that specific stereotype. And so, I certainly tell my students to A) not, you know, worry about what is supposed to be as opposed to just being themselves and, and to get their faces out there, you know, to do outreach, its so important from, you know, for so many reasons to, to do scientific outreach, not just if you don't look like the typical physicist to let kids know that, you know, they can do what they want and don't have to, you know, follow a specific path because of what they look like or who they are, but also, I mean, just the kind of public's perception of basic science and research and all that kind of stuff, I think it's really important to, to make sure that you meet people halfway and not just say that were important and you should fund us and all these kinds of things without actually explaining why and, you know, introducing them to what you do.
Becky Carmichael
[22:26] Is there a particular outreach group or event here in the Baton Rouge area that you enjoy participating in?
Catherine Deibel
[22:35] I think there's a couple that are really good. One thing that we do is actually through our Physics and Astronomy Department is called Saturday science. So it's once a month I believe, and it's a Saturday morning at 10, which is not too early. So it's um, its a public lecture given by typically an LSU professor, but in any department across the College of Science, or I think also in engineering as well, basically any sort of STEM related fields. So it's not, even though it's run through the physics department, it's not just physicist. And it's just open to whomever I think a lot of high schools will give extra credit for, you know, their students attending, but also, I gave one in October, and they were a lot of middle school age kids, there is that kind of thing, which is really great. And, and it's just a way to sort of reach out to the community and give a public talk. There's also public talks at the Highland Observatory, which I think are really great. And so all those kinds of sort of outreach events that go out to the public that you know, try to frame science in a way that you don't have to be a scientist to understand and really bring in the public and encourage them to ask questions and, and understand why funding basic research and studying these things is important.
Becky Carmichael
[23:58] Catherine Is there anything else that you want to share that we haven't, we haven't touched on.
Catherine Deibel
[24:05] I think that the sort of main themes of, you know, what I do have been covered pretty well. And, you know, again, just the sort of importance of basic research, especially in the climate that we're in these days where there's not, you know, quote, unquote, post factual world is a little disturbing, as a scientist, to kind of see that push back to, to, to fact based thinking and that kind of thing. So I think it's really important to kind of explain to the broader public, you know, why facts are important and why basic research is important. And you know, that it's, if we don't continue to fund these kinds of things, we won't have the next cell phone discovery or the next, you know, technological development.
Becky Carmichael
[24:59] Dr. Deibel, it's been a pleasure speaking with you today. I've enjoyed listening to your research and I look forward to hearing more about what you're doing in the future. Thank you.
Bailey Wilder
[25:10] Experimental was recorded and produced in the KLSU Studios here on the campus of Louisiana State University and it's supported by LSU Communication Across the Curriculum and the College of Science. Today's interview was conducted by Becky Carmichael and edited by Bailey Wilder. To learn more about today's episode, subscribe to the podcast, ask questions and recommend future investigators, visit CXC.lsu.edu/Experimental.