Solar REU 2011 Jewels of the Sun A Statistical Study of X-Ray Bright Point Energetics Tom Elsden University of St Andrews, Scotland
Dr Steve Saar
Dr Paolo Grigis
Talk Outline Introduction to X-ray bright points Purpose of the project What have we learned? What’s left to do?
Introduction to bright points What are x-ray bright points (XBPs)?
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
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?
The Solar Corona Image, SOHO website Image, Miloslav Druckmuller
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
(The magical) Bright Point Finder
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.
Rogue Bright Points HMI MagnetogramAIA 193Å image
Aims Bright point temperatures Surrounding environment effects. Orientation Tangential flow in photosphere surrounding magnetic islands* Magnetic flux vs emission
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.
Orientation Joy’s Law & Hale’s law Expect two peaks at & degrees in top plot. Expect one peak at degrees in bottom plot.
Flow map Flow map courtesy Dr Karin Muglach
=> Bright points represent emerging magnetic flux!
Future Work Do more statistics! Much more can be done with the flow maps, magnetic flux and temperature correlations. Apply to much more data.
Acknowledgements Dr Steve Saar Dr Paolo Grigis Dr Karin Muglach NASA grant NNX09AB03G to the Smithsonian Astrophysical Observatory. Thanks SSXG!