The mystery of the North Star: Astronomers baffled to find Polaris is getting BRIGHTER -
Astronomers have discovered that Polaris, the north star, is getting brighter.
They say the star has suddenly reversed two decades of dimming.
It is expanding at more than 100 times the rate they expected - and nobody is sure why.
A team led by Scott Engle of Villanova University in Pennsylvania recalibrated historic measurements of Polaris by Ptolemy in 137 C.E., the Persian astronomer Al-Sufi in 964 C.E., and others.
They investigated the fluctuations of the star over the course of several years, combing through historical records and utilising the Hubble Space Telescope.
The team found that Polaris is 2.5 times brighter today than in Ptolemy's time, which they say is a remarkable rate of change.
'If they are real, these changes are 100 times larger than predicted by current theories of stellar evolution,' says Villanova astronomer Edward Guinan.
The team's data also hint that the star's cyclic 4-day variation in brightness, although still weak, is once again growing more robust--but no one knows what's driving these flutterings or how long they will last.
Engle and his team began to research the star around the beginning of 2000, when they found that the dropping brightness was on the rise again.
Read more: -
Astronomers have discovered that Polaris, the north star, is getting brighter.
They say the star has suddenly reversed two decades of dimming.
It is expanding at more than 100 times the rate they expected - and nobody is sure why.
A team led by Scott Engle of Villanova University in Pennsylvania recalibrated historic measurements of Polaris by Ptolemy in 137 C.E., the Persian astronomer Al-Sufi in 964 C.E., and others.
They investigated the fluctuations of the star over the course of several years, combing through historical records and utilising the Hubble Space Telescope.
The team found that Polaris is 2.5 times brighter today than in Ptolemy's time, which they say is a remarkable rate of change.
'If they are real, these changes are 100 times larger than predicted by current theories of stellar evolution,' says Villanova astronomer Edward Guinan.
The team's data also hint that the star's cyclic 4-day variation in brightness, although still weak, is once again growing more robust--but no one knows what's driving these flutterings or how long they will last.
Engle and his team began to research the star around the beginning of 2000, when they found that the dropping brightness was on the rise again.
Read more: -
http://www.dailymail.co.uk/sciencetech/article-2552530/The-mystery-North-Star-Astronomers-baffled-Polaris-getting-BRIGHTER.html
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