Bruce Carney at the Morehead Observatory
It may be a long way to Tipperary, but not compared to the distance to the center of the galaxy. And thanks to UNC scientists, the measurement of that distance is more accurate than ever before.
By measuring infrared light from pulsating stars in the constellation Sagittarius, UNC scientists have determined the most accurate estimate yet of the distance to the center of the Milky Way.
That distance is roughly 26,000 light years, or about 152,828,000,000,000,000 miles.
"People have been trying to derive the distance to the center of our galaxy for the past 75 years, and they have been converging on a reasonably good answer," said Bruce Carney, Samuel Baron professor of physics and astronomy. "We think our answer is arguably the most secure one, and the uncertainty in it is pretty small."
Besides Carney, chief author of the report is Jon Fulbright, a 1994 UNC graduate who used the research for his senior honors thesis. Fulbright is now a graduate student in astronomy at the University of California at Santa Cruz's renowned Lick Observatory.
Fulbright, Carney and colleagues from Ohio State University and Chile's Cerro Tololo Inter-American Observatory studied about 60 stars known as RR Lyraes. These stars pulsate as they near the end of their lives, and the amount of infrared light they give off provided the researchers with a basis of measurement.
"The importance of knowing the distance to the center of the Milky Way is that the answer bears on other questions such as how massive the galaxy is and how old the stars in the center are," he said. "It also bears somewhat on the current big debate about the age of the universe."
The National Science Foundation funded the research.
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