NASA: Mysterious star’s unusual dimming likely due to dust cloud, not ‘alien megastructure’

The reason behind star KIC 8462852’s mysterious dimming, which had been attributed to an extraterrestrial civilization at one point, appears to have been identified. 

“A new study using NASA’s Spitzer and Swift missions, as well as the Belgian AstroLAB IRIS observatory, suggests that the cause of the dimming over long periods is likely an uneven dust cloud moving around the star," according to a NASA press release.

“This pretty much rules out the alien megastructure theory…,” Huan Meng, the paper’s lead author noted.                    

The star—also known as Boyajian’s Star, or Tabby’s Star—became a point of interest after scientists noticed it exhibiting an unusual long-term dimming trend including a short period where its light appeared to fall by as much as 20 percent. 

RELATED: NASA launches Operation IceBridge to study Antarctica

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NASA launches Operation IceBridge to study Antarctica
ANTARCTICA - OCTOBER 31: A section of ice near the coast of West Antarctica is viewed from a window of a NASA Operation IceBridge airplane on October 31, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 31: IceBridge Project Scientist Nathan Kurtz looks out over ice near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 31, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of up to 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 31: A section of the West Antarctic Ice Sheet with mountains is viewed from a window of a NASA Operation IceBridge airplane on October 31, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 31: A section of the West Antarctic Ice Sheet is viewed from a window of a NASA Operation IceBridge airplane with the airplane shadow visible on October 31, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Ice crevasses are viewed near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Ice floats near the coast of West Antarctica as viewed from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Tabular icebergs float near the coast of West Antarctica as seen from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Sea ice streaks are viewed near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Sea ice floats near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Ice is viewed near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA- OCTOBER 28: NASA flight suits hang inside a NASA Operation IceBridge DC-8 research airplane on October 28, 2016 flying near the coast of Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Mission scientist John Sonntag works inside a NASA Operation IceBridge DC-8 research airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 28: Ice is viewed near the coast of West Antarctica from a window of a NASA Operation IceBridge airplane on October 28, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA - OCTOBER 27: Ice floats in West Antarctica as seen from a window of a NASA Operation IceBridge airplane on October 27, 2016 in-flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
ANTARCTICA- OCTOBER 27: Ice floats near the coast of West Antarctica as viewed from a window of a NASA Operation IceBridge airplane on October 27, 2016 in flight over Antarctica. NASA's Operation IceBridge has been studying how polar ice has evolved over the past eight years and is currently flying a set of 12-hour research flights over West Antarctica at the start of the melt season. Researchers have used the IceBridge data to observe that the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. NASA and University of California, Irvine (UCI) researchers have recently detected the speediest ongoing Western Antarctica glacial retreat rates ever observed. The United Nations climate change talks begin November 7 in the Moroccan city of Marrakech. (Photo by Mario Tama/Getty Images)
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So the team began observing the entity using multiple instruments and eventually determined that the blocking particles are likely fairly small in diameter but “bigger than interstellar dust.” 

Based on these parameters, a dust cloud was considered the most likely cause behind the dimming because, as the release explains, “Dust that orbits a star, called circumstellar dust, is not so small it would fly away, but also not big enough to uniformly block light in all wavelengths.”

Despite the finding, the cause behind the star’s shorter-term and larger dips is still unknown.

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