Astronomer’s discovery of cool ‘stars’ among top 100 scientific stories of 2011

February 22, 2012 | News, UToday
By Feliza Casano

A discovery by a University of Toledo researcher is among the top scientific findings of the year, according to Discover Magazine.

Dr. Michael Cushing in Brooks Observatory

The detection of cool star-like orbs called Y dwarfs made by a team of scientists that included Dr. Michael Cushing, UT assistant professor of astronomy and director of Ritter Planetarium, was listed as No. 66 on Discover Magazine’s top 100 list of discoveries for 2011.

“It’s exciting because there is so much great science being done all over the world,” said Cushing, who was a member of the NASA team that discovered the cooler stars and the lead author of a paper describing them. “It is a real honor for our work to be selected as one of the top 100 discoveries of 2011.”

Y dwarfs are actually the coolest class of brown dwarfs. Unlike most stars, brown dwarfs are not hot enough to sustain nuclear fusion deep in their interiors. Without this internal energy source that keeps stars like our sun shining for billions of years, brown dwarfs simply cool off as they age, Cushing said.

“Astronomers classify stars based on their temperature, using an odd collection of letters beginning with the hottest ‘O’ stars and, until recently, ending with the cool ‘M’ stars,” Cushing said. “During the last 15 years, we’ve been finding cooler and cooler brown dwarfs, and ‘Y’ represents the latest addition to this system.”

The Y dwarfs originally were identified with information from NASA’s Wide-field Infrared Survey Explorer, or WISE, which took a survey of the entire sky in infrared. Subsequently, the team did follow-up research using ground-based telescopes, including one in Hawaii, as well as the Hubble Space Telescope.

Y dwarfs can be as cool as room temperature. One Y dwarf called WISE 1828+2650 is about 300 degrees Kelvin. In comparison, the sun’s temperature is about 6,500 degrees Kelvin.

Cushing, who joined UT in August 2011, will conduct additional research at the University to learn more about these colder stars.

“I’m looking forward to continuing my study of these elusive objects,’’ he said. “We’ve just begun our study of the Y dwarfs, and there are still many questions to be answered about their properties.”

To read the Discover Magazine article, “Found: Stars Cool Enough to Touch,” click here.

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