Whole Earth Telescope brings international cooperation to cosmic proportions
December 14, 2011 - Like an international relay team with telescopes, astronomers worldwide are working together to continuously watch several cooling stars for clues that may help reveal one of our galaxy’s deepest secrets: its age. Click, click, click, observers manning over 30 major telescopes in 12 countries have been taking pictures of the target white dwarf stars every 20 seconds from sundown to sunup for the past four weeks and transmitting the images to researchers at the University of Delaware.
The UD team is coordinating the global effort -- aptly named the Whole Earth Telescope (WET) -- from a command center at Mount Cuba Astronomical Observatory in Greenville, Del.
There, for the first time, astronomers are exclusively using a software program called “Maestro,” developed by UD doctoral student James Dalessio, to automatically process the hundreds of gigabytes of images to study variations in the brightness, or temperature, of each star.
“The Whole Earth Telescope receives tens of thousands of images every day from observatories all over the world, and Maestro is saving us hours of tedious work,” says Dalessio, who has coordinated a large portion of the observing run. A native of Woodstown, N.J., Dalessio is midway through his doctoral program in the Department of Physics and Astronomy at UD. His work on the WET project is supported by the NASA-funded Delaware Space Grant Consortium.
“Just today, I have communicated with observatories in Croatia, Germany, South Africa, Mexico, Chile, Brazil, China, Taiwan, Texas, Arizona, Canary Islands, Hawaii, Poland, Hungary and Slovakia,” Dalessio notes. “It’s a huge team effort.”
Dalessio’s adviser, Judi Provencal, assistant professor of physics and astronomy at UD, organized the star watch, working with Gerard Vauclair, an astronomer from the Observatoire Midi-Pyrenées in Toulouse, France. Vauclair is in charge of HS0507+0434B, the target star for telescopes in the Northern Hemisphere, and Dalessio is the chief investigator for the primary southern target, EC04207-4748. Five secondary target white dwarfs also are being watched.
White dwarfs are “dead” stars because they have no source of energy. They are just radiating their residual heat into space like an electric stove that’s been turned off after cooking a meal, explains Provencal, who directs the Delaware Asteroseismic Research Center at UD.
“Astronomers can calculate how long it takes for a white dwarf to ‘cool off,’” Provencal notes. “We’ve looked around for the coolest white dwarf we can find, and then figured out how long it took to get to that temperature, and that is the age of the galaxy. Turns out to be between 9 and 11 billion years. Of course, we’d like to be more precise than that, so we need more observations.”
One byproduct of the study is a search for planets around white dwarfs. More than half the stars astronomers see in the sky have a planetary companion, Provencal says, but what will happen to these planets -- like Earth -- as their stars age and die out?
“If we find some planets around white dwarfs, perhaps these planets survived the death of their suns, and maybe some of our solar system planets will survive. So far, we haven’t found any,” she notes. “So maybe all of the planets will be ejected from the solar system to wander through interstellar space.”
Although most of the participating telescopes are manned, with observers in the dome, several are operated robotically. A telescope in Arizona is actually owned and remote-controlled by colleagues in South Korea, and the observer at the Tuebingen telescope in Germany can run his telescope from his living room, Provencal says.
In Chile, UD researchers were granted permission to use PROMPT, a series of robotic telescopes whose primary duty is to monitor gamma ray bursts, big explosions in the distant galaxy.
Whether aided by robotics or not, the Whole Earth Telescope has had its share of cosmic quirks and earthly challenges during its most recent campaign, but the cosmic collaboration is taking them in stride.
“We had an asteroid eclipse one of our stars, and we imaged what was either a distant weather balloon or satellite. Maybe it was just some aliens,” Dalessio says, smiling. “It’s been cloudy in a lot of places, and some telescopes have been closed due to snow. It’s all very exciting. When this run is over, I’ll probably need a good 24 hours of sleep.”