Keeping an eye on the night sky
Nov 17, 2016 09:50AM
● By J. Chambless
(Photo courtesy of University of Delaware) Dr. Judith Provencal is the resident astronomer at Mt. Cuba Observatory and coordinates the Whole Earth Telescope.
By Lisa Fieldman
The term “stargazer” is often used to describe a person who is a daydreamer, or a person who is absorbed in a world of fantasy. Perhaps someone who is not quite tethered to earthly reality.
Dr. Judith Provencal definitely is a stargazer. But when her head is in the clouds, you can be sure it is for research purposes only. This down-to-earth scientist teaches astronomy at the University of Delaware, is the resident astronomer at Mount Cuba Observatory, and also coordinates the Whole Earth Telescope program (WET). Working with WET, she manages an international network of telescopes that are focused around the clock on the dead stars known as white dwarfs.
“I’ve always liked the stars,” she said. “When I was young, I had a little telescope and I would go out in the snow to look at the sky. My parents thought their daughter was crazy."
Back then, she could easily find the Andromeda galaxy because the Maine sky was so dark. Her youthful fascination has become her life’s work.
Provencal earned her bachelor’s degree in physics and astronomy from Smith College. “I wanted to study astronomy,” she recalled, “but as a freshman I was told that I also had to study physics.”
She was not too happy about the physics, “but once you get past the first boring classes, it’s really kind of cool," she said.
Provencal chose Smith College, not only for its outstanding education, but also because they had a barn. “I always wanted to take riding lessons,” she said with a smile.
Provencal was awarded her master’s degree and Ph.D. in astronomy from the University of Texas. Her thesis adviser was one of the founders of the Whole Earth Telescope. You could say that her love of horses opened the door to a new passion.
“My adviser had horses, and I was looking for a place to ride,” Provencal explained. The adviser loaned her a horse and introduced her to the Whole Earth Telescope program.
“That’s how I got involved with WET, through horses,” Provencal said. After graduation in 1994, she was Dr. Harry Shipman’s post-doctoral researcher for three years at the University of Delaware. Shipman and Provencal worked well together, and a few years later, he helped her secure the resident astronomer position at Mt. Cuba. Provencal also began teaching in the university’s physics and astronomy department.
When the Whole Earth Telescope founders decided to hand over the reins in 1996, Provencal secured funding from The Crystal Trust to bring the program to the University of Delaware and Mt. Cuba.
“They call it the Whole Earth Telescope because you use the earth as a rotating platform to keep at least one telescope pointed at a target star at all times," she said. There are about 50 observatories participating in the studies worldwide.
Provencal determines which star will be viewed, and then coordinates viewing duties among observatories that are dotted all over the globe. She routinely communicates with astronomers working in high-tech observatories, as well as in remote viewing outposts such as Peak Terskol in the Caucasus Mountains of Russia. She enjoys the camaraderie that has developed among her WET colleagues, and often travels to partnering observatories for viewings and meetings.
Why all the interest in white dwarfs? A white dwarf is a dead star. “It’s just a big ball of carbon and oxygen sitting up there cooling off,” Provencal said. However, when these dead stars get to a certain temperature range, they start to pulsate -- repeatedly growing brighter then dimmer.
“The fun thing is, we can use the pulsation frequencies to view what’s inside the star,” Provencal explained. White dwarfs send pulsations through the star from the core to the surface. If the body of the star is homogeneous, the frequency will go right through without disruption. But if the frequency hits an aberration in the star, the pulsation will change. By mapping these anomalies, astronomers can map the star.
Provencal compares herself to an archaeologist. “I can find out how much carbon and oxygen are in the structure. We can figure out what is going on inside the star right now,” she said.
Asteroseismology is a relatively new science and is similar to using seismic waves to study earthquakes. The data gathered about these dead stars will help our understanding of active stars.
“A star like the sun has all this nuclear fusion going on that we really don’t understand,” she said. “We have models and physics, but we don’t know all the physics. The fact that we don’t know everything introduces a lot of error in our understanding.”
Provencal has one star in particular that's her favorite It is named GD358 and it is located in the constellation Hercules. “It does all kinds of crazy stuff, so it’s fun to observe,” she said with a smile.
The pulsation patterns change every couple of years, which is intriguing to the astronomer. In the lobby of the Mt. Cuba Observatory, there is a display dedicated to her favorite white dwarf, showing photos taken by her students, and years of data collected from the start of the WET program. She will most likely continue to study her favorite star, since it will continue to pulsate for few more million years before it is gone.
On a recent clear evening, Provencal readied the Mt. Cuba telescope for the scheduled watch of target GD2938. “I just read my emails and the telescope in Poland is cloudy,” she said. Another observatory was also cloudy, leaving Mt. Cuba as the only one with clear observation for that viewing period.
She opened the slit in the dome, and lowered the temperature on the telescope to cool it down. “This is the original telescope,” she said. “I believe it saw first light in 1963.”
Provencal is very fond of the 24-inch refracting telescope, which she refers to as “my telescope.” Next, she attached the camera, then rotated the telescope to the proper position for shooting the star. Once in position, the scope tracks the sky with the aid of an electric motor. Firing up the computer, Provencal chose the filters needed for the best results and ran the necessary diagnostics. She routinely programs the computer to shoot 800 to 1000 pictures per night.
“That way, if I doze off for ten minutes I don’t feel guilty,” she said with a laugh.
The telescope does not have remote operation capabilities, but the computer will control the camera throughout the viewing time. So while no one needs to be present to actually click the shutter, the telescope and viewing dome are manually operated. Provencal needs to be on hand to check things throughout the night and shut everything down at the end of the shift, so there is a lot of downtime.
“Back when I was a graduate student, every few minutes, you had to look through the eyepiece and make sure your star was still centered,” she said.
Plans for building the Mt. Cuba Observatory began in 1958, with the grand opening occurring in 1963. History suggests that the idea for the observatory was inspired by Miss Annie Jump Cannon. She was born in Dover, Del., and is one of the most recognized astronomers in the world. She created a unique star classification system that is still in use today. She also discovered many new stars.
Cannon was a pioneer in the field of astronomy, and an early inspiration for women in all the sciences. The successful launch of Sputnik in 1957, followed by the United States' Explorer satellite and the subsequent creation of NASA, most likely stirred local interest in astronomy. The observatory originally housed the 24-inch telescope, a workshop, library and darkroom. Ten years later, Francis duPont donated his refracting telescope, and an additional viewing dome was added, along with a lecture room and planetarium. Mt. Cuba is the only public observatory in Delaware and offers community viewing programs on many Monday evenings throughout the year.
Provencal and Budd Howard, a technical associate with Mt. Cuba, are working on a proposal to bring a larger telescope to the observatory.
“Originally, we were thinking about replacing the 24-inch telescope,” Provencal said. “But there is a lot of nostalgia for the old 24-inch.”
The consensus was that the telescope should stay. Since they can’t replace the telescope, the next option is to upgrade to a new one. The new telescope will have a 36-inch lens and will be equipped with all the current technology. This scope will even have remote capabilities, so the astronomer can operate the telescope from any location. The project will necessitate the construction of a new viewing dome as well.
Provencal recently visited Brigham Young University to talk telescopes. The university is using the same telescope she wants to acquire for Mt. Cuba. She asked lots of questions from both a scientific and business viewpoint.
“I’m a scientist, so I think about what I need for my science,” she said. “But the board members are businessmen, and they have completely different questions.” If this project comes to fruition, the telescope will be built by DFM Engineering, a U.S.-based company.
The world’s most powerful telescope is currently being built in the foothills of the Andes. The Large Synoptic Survey Telescope has a field of view that is almost 40 times the size of the full moon. “They will be taking a picture of the whole sky, three times a night, for 10 years,” Provencal said.
The scope will be able to look deeper into the night sky and pick up light from dimmer bodies. “When I first started graduate school, we were aware of about 40 white dwarfs, but with bigger telescopes and more people out observing, there are now about 2,000, and that’s going to keep increasing," she said.
As we develop the ability to study more white dwarfs, the additional data will allow us to have a better understanding of both dead and active stars.
Gazing through the telescope at the moon, Provencal still seemed to marvel at the sight. Asked if she believed in life on other planets, she said, “Yes. The universe is 13 billion years old. There could be civilizations out there that are so much older than us. It would be a vast waste of space if there were not life on other planets.”
As for our sun, she said that it won’t become a white dwarf for a few billion years. “That’s not something we have to worry about right now,” she said with a laugh.
Information about the Whole Earth Telescope and the Delaware Asteroseismic Research Center (DARC) can be found at www.physics.udel.edu/gp/darc. Find out about events and programs at the Mt. Cuba Observatory at http://mountcuba.org.