Tag Archives: NMSU

A Thesis, Proposed

Graduate school is a bit of an odd beast. It’s not really college, it’s not quite a job, and it’s certainly not easy. In the US, getting a PhD in the sciences typically involves a couple years of classes, several exams, some work as a teaching assistant, and eventually a self-directed research project called a thesis. The whole shebang takes some 4-8 years on average. AstronoMerrdiff’s graduate school journey began in San Diego with a somewhat atypical MS-only program, and then wound its way to Las Cruces for a PhD. (The “normal” path is to earn a Master’s degree en route to the PhD at a single institution.) Finally, back in February, after years of related and not-so-related research, successfully completing a host of departmental prerequisites, and a hectic few days of last-minute changes, I stood in front of my department and outlined the project I will undertake for my thesis dissertation:

Red Giants in Eclipsing Binaries
as a Benchmark for Asteroseismology.

Any questions? …Well, since this is my primary purpose in life for the next while, I figure the least I can do is spend a few paragraphs explaining my own little corner of astronomy.

In a nutshell, I’m studying red giant stars that are in eclipsing binary systems. Many of the giant stars have sound wave oscillations going on inside that we observe as small changes in brightness (this is called asteroseismology, and tells us about a star’s interior which is otherwise impossible to see). But not all of the giant stars oscillate. I want to figure out why. The fact that these stars are in eclipsing binaries makes them relatively easy to physically model and characterize. We think the oscillations might be weaker or non-existent when there are lots of starspots or tidal forces, but we’re not sure.

Want more? Here is the talk I gave for the “Three Minute Thesis” Competition held recently at my university. While I didn’t win, I thought I did pretty well. My classmate Kyle Uckert took home first place for his outstanding talk about searching for microbial life on other worlds. I had a lot of fun, though, and I learned how challenging it is for me to give a talk without visual cues (like multiple slides) and a strict time limit.

3min_thesis_slide_mrawls
My slide for the Three Minute Thesis Competition. Image credits: G Perez, IAC, SMM (left), NASA (right), J Orosz (right)

Have you heard about how we’ve found over 1000 planets orbiting distant stars?

The Kepler space telescope finds planets by staring at stars. When a planet passes in front of a star, we see less light. This technique lets us not only DETECT planets, but also characterize them. For instance, a big planet will block more light than a small one.

OK, so, planets are great, but that’s not what my thesis is about. I study stars! It turns out that Kepler is also incredibly useful when the situation is a little different: instead of a planet orbiting a star, you have two stars orbiting each other.

Just by observing how the brightness changes with time, we can learn a lot of things about these binary stars, such as how long it takes for them to go around once and how much hotter one is than the other.

But Kepler alone doesn’t give us the full picture. For that, I use a telescope right here in New Mexico, at Apache Point Observatory, which spreads out all the different colors of light into a rainbow. I watch characteristic dark areas move from red to blue and back again, which tells me the velocities of the stars as they orbit. I then use that information together with the data from Kepler to get sizes, masses, and other properties for both stars.

Now, let me step back for a moment and ask: why do we care? Well, stars are astronomers’ main tool. Unlike other sciences, we can’t interact with what we study. What we CAN do is carefully measure light. And virtually all of the light we see bouncing around the Universe started out deep inside a star. So wouldn’t it be nice if we could look deeper and study the interiors of stars?

As it turns out, many stars, including our Sun, have sound wave oscillations going on inside that we can observe as small changes in brightness. And just like earthquakes help us study the interior structure of the Earth, these STARquakes let us study the insides of stars. This is called asteroseismology.

Conveniently enough, some of the biggest stars oscillate slowly enough that our friend Kepler can see it. This includes Red Giants, the kind of star our Sun will become when it runs out of hydrogen fuel in a few billion years.

In fact, based on what we know about their insides, we think ALL Red Giant stars should have these starquakes. So, we were surprised when we found several Red Giants that DON’T.

The good news is, because these stars are in binaries, that makes them relatively easy to study. I’m looking at binary stars with Red Giants that DO oscillate, and comparing them to binary stars with Red Giants that DON’T. Along the way, I’m using the systems that DO oscillate as a way to check quantities like mass and size that we can get from both techniques.

My research uses observations of binary stars together with asteroseismology to learn how all stars live and evolve.

One Astronomer’s Giant Leap

The following was originally published at Astronomy.com, and was drafted during ComSciCon, a science communication workshop for graduate students.

Astronomers are accustomed to dealing with mind-bogglingly huge distances. But for one professor in Las Cruces, New Mexico, the biggest distance to overcome can be just a few miles.

Dr. Nicole Vogt is a professor of astronomy at New Mexico State University, a land-grant university in southern New Mexico located 45 miles from El Paso, Texas. The area is largely agricultural, and many students come from nontraditional backgrounds or can get to campus only one or two days a week. Vogt teaches an introductory astronomy course that fulfills a lab science requirement for undergraduates, but students’ lives can make attendance prohibitively difficult. Some live over an hour from campus, others work a demanding job with long hours, while others have family responsibilities. When this happens, students often turn to distance education, but they come up short without a lab science.

How do you earn credit for a laboratory class without, well, attending lab? The usual answer is simple: You don’t. Vogt finds this unacceptable.

“Providing distance access to a core curriculum can broaden the participation of underrepresented groups in higher education,” she says. The problem is: How do you create lab exercises that can be completed without specialized equipment or face-to-face interactions with instructors and peers? The whole point of a science lab is hands-on learning. Reading a textbook or writing a paper just isn’t the same as gathering data and drawing conclusions.

To address this, Vogt is developing the General Education Astronomy Source (GEAS) project at New Mexico State. Essentially, GEAS is an online astronomy course with a do-it-yourself lab built in. It is specifically designed for students to work at their own pace. They can review basic math and science skills as needed while exploring current astronomy topics. Most importantly, they are free from scheduling constraints — in both location and time.

By watching General Education Astronomy Source videos, class registrants can watch other students performing experiments, like this still from the lunar cratering lab, before trying it themselves. // all photos courtesy Nicole Vogt
The GEAS project is composed of four main components: an online self-review library, a set of lab exercises with accompanying videos, audio lecture recordings, and short films featuring diverse individuals with careers in astronomy and related fields. Taken together, these elements form an interactive, hands-on experience that fulfills New Mexico State’s lab science course requirement.
 

Bringing a lab to the Internet is a unique challenge. To make a lab exercise accessible to distance learners, Vogt and her team began by adapting classic assignments to work with common household materials and a computer. “We promote hands-on learning through physical experiments that students conduct on their own,” she says.

For example, to track the position of the Moon over a two-week period, students build a simple sextant — a protractor for the sky — using cardboard, pins, thread, and tape. In another exercise, students use a Web application to explore pictures of galaxies and analyze their properties.

Students of the General Education Astronomy Source project also use special Web applications, like this one to analyze galaxy properties, to complete lab projects.

One lab is all about craters. Students learn that planetary scientists can estimate how fast a projectile was moving when it hit the Moon’s surface by measuring the size of the resultant crater. After looking at several pictures, students round up a bucket, some sand and flour, a measuring tape, and a marble. They proceed to drop the marble from various heights and make their own craters to investigate the relationships between drop height, projectile speed, and crater size.

Developing projects that can be done at home, however, is only the first step in a successful do-it-yourself lab. What if students don’t understand the instructions? What if they make a mistake but don’t realize it? What if they get frustrated or have a question? In a traditional lab, the instructor can provide assistance and feedback in real time. There is no such luxury in distance education.

Dr. Nicole Vogt demonstrates how to use a homemade sextant in one online lab video tutorial.

To keep tabs on student progress, Vogt uses Google Drive, an online utility that allows collaborators to view and edit documents in real time. Each student keeps a lab report document where they record data and answer questions. The collaborative nature of Google Drive lets the instructor see student responses before an assignment is due. This effectively mimics the instructor-student interaction in a traditional lab course. For instance, if a student mistakenly concludes that faster projectiles make smaller craters, the instructor can leave a comment to ask if there was a problem performing the experiment.

Vogt points out that GEAS is a work in progress but has come a long way. The unique format of the lab exercises can present a daunting learning curve, as many students are used to online courses requiring little work. That said, students who persevere through the first couple of lab exercises typically come away with an appreciation for how much they have learned.

The GEAS project has the potential to have far-reaching impacts: beyond New Mexico, materials are currently being used in California, Virginia, Michigan, and even Canada. “Our lab exercises are available free of charge to astronomy instructors worldwide,” Vogt says. “By increasing access to laboratory science courses through distance learning, we can remove a significant barrier to completion of the bachelor’s degree.”