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Solar REU 2011 Jewels of the Sun A Statistical Study of X-Ray Bright Point Energetics Tom Elsden University of St Andrews, Scotland
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Dr Steve Saar
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Dr Paolo Grigis
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Talk Outline Introduction to X-ray bright points Purpose of the project What have we learned? What’s left to do?
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Introduction to bright points What are x-ray bright points (XBPs)?
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Basic Facts What do we know about them? Lifespan: 2 hours – 2 days Size : 2-10 x10 4 km Found at all latitudes Temperature :1-2MK Numbers: 100s – 1000s Emerging magnetic flux
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Purpose of study Perhaps small scale tells us of large scale These little guys are relatively unstudied Are all XBP’s simple magnetic bipoles? What energizes them?
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The Solar Corona Image, SOHO website Image, Miloslav Druckmuller
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Coronal Temperature Generally defined > 10 6 K. Sharp rise in temperature, we believe to be caused by strong magnetic fields. We can see the wavelengths used to observe bright points. Image, Astronomy and Astrophysics
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(The magical) Bright Point Finder
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In the beginning… Analysed the magnetic field in the photosphere. Observed that this was not going to be as simple as first planned. ‘Simple bipoles’ didn’t quite cover it.
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Rogue Bright Points HMI MagnetogramAIA 193Å image
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Aims Bright point temperatures Surrounding environment effects. Orientation Tangential flow in photosphere surrounding magnetic islands* Magnetic flux vs emission
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We see a relatively normal distribution, with a gap to higher temperature BP’s caused by using the 211 filter for higher temperature bright points rather than 171 or 193.
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Orientation Joy’s Law & Hale’s law Expect two peaks at 315-360 & 180-225 degrees in top plot. Expect one peak at 315-360 degrees in bottom plot.
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Flow map Flow map courtesy Dr Karin Muglach
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=> Bright points represent emerging magnetic flux!
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Future Work Do more statistics! Much more can be done with the flow maps, magnetic flux and temperature correlations. Apply to much more data.
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Acknowledgements Dr Steve Saar Dr Paolo Grigis Dr Karin Muglach NASA grant NNX09AB03G to the Smithsonian Astrophysical Observatory. Thanks SSXG!
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