Eclipses yield first images of elusive iron line in the solar corona

NASA/Goddard Space Flight Center ^ | Jan 4, 2009 | Unknown

[decimon]

GREENBELT, Md. – Solar physicists attempting to unlock the mysteries of the solar corona have found another piece of the puzzle by observing the sun's outer atmosphere during eclipses.

Ground-based observations reveal the first images of the solar corona in the near-infrared emission line of highly ionized iron, or Fe XI 789.2 nm. The observations were taken during total solar eclipses in 2006, 2008, and 2009 by astrophysicist Adrian Daw of NASA's Goddard Space Flight Center in Greenbelt, Md., with an international team of scientists led by Shadia Habbal from the University of Hawaii's Institute for Astronomy (IfA).

"The first image of the corona in Fe XI 789.2 nm was taken during the total solar eclipse of March 29, 2006," said Daw.

The images revealed some surprises. Most notably, that the emission extends out at least three solar radii—that's one-and-a-half times the sun's width at its equator, or middle—above the surface of the sun, and that there are localized regions of enhanced density for these iron ions.

Combined with observations of other iron charge states, the observations yield the two-dimensional distribution of electron temperature and charge-state measurements for the first time, and establish the first direct link between the distribution of charge states in the corona and in interplanetary space. "These are the first such maps of the 2-D distribution of coronal electron temperature and ion charge state," said Daw.

Mapping the distribution of electron temperature and iron charge states in the corona with total solar eclipse observations represents an important step in understanding the solar corona and how space weather impacts Earth.

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The scientists' results will be presented at the American Astronomical Society meeting on January 4 in Washington and published in the January issue of the Astrophysical Journal.

For more information and related images, visit:

http://www.nasa.gov/centers/goddard/news/topstory/2010/aas-eclipse.html

[decimon]

Ion cross ping.

[El Sordo]

Nifty.

[texmexis best]

I’ve been wondering where I put that pesky ionized iron line.

Thanks guys.

[Roccus]

We are the stuff of stars.

[RonF]

Hm. Iron in a star is quite significant. No atom heavier than iron can be formed by a fusion reaction that releases energy. Forming any atom bigger than that requires a net consumption of energy. So when a star first starts it's fusion reactions, hydrogen fuses to form helium. Various reactions go from there to fuse atoms into heavier and heavier elements. The heat and radiation from these reactions expands the size of the star and keeps it going. But as the reactions form heavier and heavier elements, each reaction releases less energy than the last.

Eventually the star, filled with iron, stops runnning sufficient fusion reactions to keep it expanded. It then collapses. The jump in pressure kicks off fusion reactions that cause an explosion, a supernova. Atoms heavier than iron are formed in that explosion (lots of energy for a short time, no need to be self-sustaining) and scattered about. Eventually those heavy elements (to an astronomer, "metal" = any element heavier than hydrogen) condense into lumps that may in turn coalesce into planets.

Joni Mitchell and Carl Sagan were right - we all are made of star dust.

You're bound to see some iron in lots of stars, but you don't want to see a lot in the one you're orbiting.

[mentor2k]

so in non-astrologer terms, is this showing the star we’re orbiting to contain some iron or a lot?

[Reily]

Please don't use astrology when you mean astronomy !
There is a universe of difference between the two words.

[SunkenCiv]

Wow, thanks decimon. I found the Oliver Manuel folder (he was arrested a couple of years ago for molesting his own children) which is pertinent to this, there's even an FR topic about it, or sort of anyway. And a search shows I reposted #49 in there here. :')

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[mentor2k]

Ha, yes my bad, I meant to say, “to the Non-Astromomer . . . “