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Journey Among the Stars

By: Virginia R. Nickles / Intern
July 6, 2001

"Twinkle, twinkle little star. How I wonder what you are." As a child, I recited this nursery rhyme every time I gazed up at the night sky. My fascination with the stars and the secrets, beauty, and marvels they hold began with this simple child's lyric. So when I found myself sitting inside a telescope dome in Kitt Peak, Arizona working with a 4-meter telescope, I could not help but begin to recite the well-known words. "Up above the world so bright, like a diamond in the night. Twinkle, twinkle little star. How I wonder what you are."

Curiosity points me towards my road.

Because of my childhood fascination, I took an introductory level astronomy class my sophomore year at Vanderbilt University. Professor David Weintraub, who taught the class, corrected many of the misconceptions I had about astronomy. And in the laboratory course that accompanied the lecture, graduate student Jeff Bary taught me how to study the stars.

Bary showed me those twinkling diamonds up close while Weintraub explained to me that my favorite nursery rhyme was not exactly accurate. He told me that the stars do not really twinkle! Stars emit a steady stream of light. They only appear to twinkle due to atmospheric effects that break up the light waves.

Think of a star as a flashlight that has been switched to 'on'. The flashlight emits a constant stream of light as stars do. First, shine the light through a piece of wavy glass of the kind often used in bathrooms. Wiggle the glass back and forth and, from a distance, the light beam seems to twinkle. That is similar to what happens to starlight as it passes through small blobs of air with different temperatures and densities that constantly move around in the atmosphere. Another contributor to twinkle is dust and other particles that intermittently block some of the starlight, an effect something like waving a hand in front of the flashlight beam.

Upon learning this bit of information, I began to wonder what other misconceptions I might have about the stars above me. So it was only natural that, when I had an opportunity to intern for a semester in a research laboratory, I chose to work in Weintraub's "lab," which turned out to be an ordinary office equipped with several computers . The internship is a requirement of the Communication of Science, Engineering, and Technology program.

The journey begins

Like most people, I thought that all of an astronomer's work was done sitting at the end of a giant telescope staring up at the night sky. Naturally, the image of a little man perched on a stool below the eyepiece of a giant telescope was the first that came to mind when Weintraub asked me to accompany Bary and another of his doctoral students, Tracy Huard, to the National Optical Astronomical Observatory in Kitt Peak, Arizona. At last I would have the opportunity to get a very close look at the stars that I had spent two semesters studying in class.

I had no idea just how little I knew about how astronomers really work. There would be no staring through an eyepiece at the stars and recitation of "Twinkle, twinkle" for me.

My work at Kitt Peak was centered upon one telescope inside a dome ten stories high. As we drove from Tucson to Kitt Peak, we moved farther and farther away from the city noise and lights. Bary explained that large telescopes must be isolated from city lights and traffic to gather the best data. So a great amount of research is put into choosing the best location. These sites tend to be high on a mountain, to have good weather for the majority of the year and to be at a substantial distance from large light sources, like cities, factories and interstate highways.

When we finally reached the top of Kitt Peak, which rises 7,000 feet above sea level, I was surprised to see not one, but many telescope domes. There were domes with the curved rounded top that fit the image I had in my head, but there were also square-, triangular-, and pentagonal-shaped domes. As I looked around, I tried to imagine the research that was to take place in each dome that night.

After dropping off our bags in the closet-sized rooms we were assigned, the three of us hurried off to the cafeteria to grab a quick dinner and place an order for the midnight meal that we would eat later at the telescope. At 6 p.m. our night was just beginning. There were data to collect and enough work to keep us busy until 6 a.m. the following morning when the sun rose.

As we drove up to our telescope, my excitement and anticipation grew. I could not wait to stare through that eyepiece for my closest look ever at the beautiful twinkling stars. As we stepped out of the elevator into a control room full of computers, monitors and recorders, however, I quickly realized that what we would be doing there is nothing like what I had imagined. As I walked through the control room into the dome itself, I stared up at the massive telescope. The many pictures of telescopes and domes that I had seen had not prepared me for the emotion of actually standing at the base of a structure so perfected and specialized. The room was cold and immaculate. I later learned that the cool air keeps moisture from building up on the lens, mirrors, and other parts of the telescope and the extreme cleanliness insures that all the intricate parts that make up the telescope stay in perfect working condition.

Where we hope our journey leads

Our telescope, the 4-meter, was equipped with a special electronics system called Phoenix. Its designer, Ken Hinkle, gave us our initial tour. At the bottom of the telescope was a cage that contained the electronics gear. Hinkle opened the cage door, climbed in and invited us to take a closer look. Bary, Huard and I carefully joined him in the cramped compartment to learn more about Phoenix and its research capabilities.

Hinkle explained that Phoenix collects the starlight that the telescope gathers from the infrared part of the spectrum. Originally called 'calorific rays,' infrared light is the byproduct of heat. Even objects that we normally consider to be cold, like ice, emit infrared radiation. Astronomers use infrared light as a window to study areas of the heavens that they cannot see with visible light, such as regions of star formation and the center of the galaxy, because clouds of dust and gas obscure them. Phoenix divides this light into different wavelengths by running it through a prism-like grating. The spectrum that it produces gives astronomers an amazing amount of information, such as the identification of specific molecules that exist hundreds and thousands of light years away. All this equipment is operated from the control room and the data is recorded on a computer for later analysis.

With the data gathered on this trip, we hoped to get some new insights into the question, "How long does it take planets to form?" According to current theory, it takes about 10 million years to make a planet the size of earth. One problem with this theory, however, is that some stars like our sun that have planets appear to have lost their surrounding cloud of gas and dust in three million years. So Weintraub and Bary have proposed that planets may actually form faster than popular theory suggests. We would be looking at "T Tauri" stars, which are very similar in size and chemical makeup to our sun. Using Phoenix we hoped to gather data on the molecular hydrogen surrounding T Tauri stars to determine how much of the gas is present around these tars, where it is located in relation to the star, and what is causing it to glow.

A few bumps along the road

As I quickly discovered, no matter how hard an astronomer works on setting up the telescope, equipment and data recorders, there are some aspects to research that he or she cannot control. I experienced one of these "bumps along the road" first hand on my first night at Kitt Peak. At 8 p.m., when we had finished our telescope tour and become acquainted with all the instruments, we began preparations to open the dome. But, before we were ready to open the doors, we were notified that telescopes on the peak could not open for several hours due to inclement weather. For the next six hours we read, talked, and watched as lightning and rain filled the sky around us. Bary and I spent hours standing on the observation deck; a window-lined hallway that circles the telescope and overlooks the flat expanse of desert that surrounds the isolated peak. We could see for miles, as lightning struck all around us in beautiful colors and varying intensity. We had the chance to talk about past observing trips he had taken and how it is customary for an astronomer to plan for a few days of bad weather when requesting telescope time.

As the rain tapered off, we made our way back to the control room where our real work would begin. With the "ok" of the head telescope operator, the doors of the dome began to open. With some disappointment we realized that the stars that were the main targets for our research had already passed overhead. So we decided to look at other stars of interest, called calibrator stars. Calibrator stars are used to take out atmospheric absorption features that can distort measurements from our stars of interest. With the help of these stars we would be able to assess more accurately whether there is any measurable emission of molecular hydrogen from our target stars.

Back on Track

The second night of observation was much more successful. The weather was perfect and we opened the dome just after sunset. We located our target stars and began collecting data. As a child I had experienced the awe of looking up at a multitude of "twinkling" stars and now I was sitting in a control room conducting research on the same amazing stars. A truly exciting moment came when we noted that we had detected molecular hydrogen from one of our stars, DoAr21. Fulfillment is the only word I can find to describe how it felt to reach such a milestone.

While the rest of our time at Kitt Peak was filled with nights of good weather and great data, it was just the beginning of the research project. Bary has spent the past nine months analyzing the data from those four nights at Kitt Peak. When he finishes, he and Weintraub will write a paper for publication that reports our observations and draws conclusions from them. Yet the journey will not end there either. From this publication other scientists will draw their own conclusions and possibly come up with their own hypotheses about the process by which planets are formed or perhaps about some other unknown aspect of the stars we studied. The universe holds many questions that astronomers seek to answer. So there are many more journeys to be had, each with its own bumps, and detours and wonderful milestones along the way.


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