You have to look heavenward through a telescope to see the object of her fascination--to pale stars called white dwarfs, their brilliance faded because all of their nuclear fuel has been burned up.
A white dwarf is a star that is “dying,” cooling down in the twilight of its life. It's what the sun will become in about 4 billion years, according to Provencal.
Starting Wednesday, March 26, Provencal--who is an assistant professor of physics and astronomy at the University of Delaware, director of the Delaware Asteroseismic Research Center (DARC), and resident astronomer at Mt. Cuba Astronomical Observatory in Greenville, Del.--will be coordinating some of the world's largest telescopes in a five-week-long “international observing run,” focusing on a white dwarf known as IU Vir in the constellation Virgo. The star's coordinates are 14012-1446.
The observing run will be conducted by the Whole Earth Telescope (WET), a worldwide network of observatories that work together to obtain continuous measurements of “pulsating” stars. Such stars change their shape or surface temperature as waves of energy travel through them. They are the basis of asteroseismology, a fledgling science that examines “starquakes” just as seismologists monitor earthquakes.
WET was initiated in 1986 by astronomers at the University of Texas and later was transferred to Iowa State University. Three years ago, the coordination of WET moved to the University of Delaware through the leadership of Provencal and Harry Shipman, the Annie Jump Cannon Professor of Astronomy at UD, and with the financial support of the Crystal Trust Foundation.
The upcoming observing run will involve more than 20 of WET's observatories, including one of the largest telescopes on the planet--the Southern African Large Telescope (SALT) in Sutherland, South Africa. It has a 10-by-11-meter (32-by-36 foot) hexagonal, segmented mirror and can record stars, galaxies and quasars a billion times too faint to be seen by the unaided eye--“as faint as a candle flame at the distance of the moon,” according to its Web site.
From March 26 through May 1, the lenses of these major telescopes will focus on IU Vir to provide 24/7 coverage. Like an international relay team, observers at Mt. Cuba in Delaware will study the white dwarf until sunrise, and then observers at Macdonald Observatory in Fort Davis, Texas, and at Kitt Peak National Observatory in Tucson, Arizona, will stand watch while the star is in their sky, followed by observers in Hawaii, then New Zealand, Australia, China and so on, around the globe.
All of the data will be transmitted to UD for analysis. Provencal and colleagues Susan Thompson, assistant director of DARC, and Teresa Holton, program coordinator, will operate the command center during the observing run, monitoring the observatories and their daily data transmissions via a Web site.
As Provencal reminds us, when we look up at the stars, the light we see has traveled millions of miles through space. It's the only artifact we have of the stars, yet this light carries with it a lot of information, allowing scientists to determine such characteristics as a star's surface composition, temperature and motion toward or away from us.
“Pulsating stars such as the white dwarf oscillate, and how they oscillate lets us determine what they look like inside,” Provencal explains. “Let's say you have a silver bell, and you ring it. It will make a certain sound. Now you have an aluminum bell that is the same shape as the silver bell. If you ring it, it won't sound like the silver bell. It will have its own tone. Stars do that, too. I like to think of our work as listening to the 'music of the stars,'” she says, smiling.
Besides giving scientists more detailed information about IU Vir, the data collected will include clues as to what is going on inside the sun because a white dwarf is the exposed core of what was once a star like the sun, according to Provencal.
“What we do might be called 'forensic astronomy,'” Provencal says. “If we can dig around in the innards of a white dwarf, and determine what it ate for lunch, how much it ate, and how quickly it ate, we can understand what is going on inside our own sun much better. We'll look at the pulsations of the star, take the frequencies at which it pulsates, and develop a model of it. In that way, this dead star which was once like the sun will help improve our understanding of the sun.”
Also, Provencal says that white dwarfs are good timekeepers, and as such, hold clues about the age of the cosmos.
A white dwarf is in the center of planetary nebula NGC6751. Near the ring of gas is a foreground star.“Once a white dwarf forms, all it does is sit and cool, so we can measure the temperature of a white dwarf, and, using some theoretical understandings, figure out how long it took the star to cool to that temperature, and hence determine how old it is,” Provencal says. “The coolest white dwarf we know of is about 2,500 degrees,” she notes. “This corresponds to an age for the galaxy of about 10 billion years.”
For more information about UD's Delaware Asteroseismic Research Center, visit [www.physics.udel.edu/darc/index.html].
Article by Tracey Bryant
Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center
A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology