ScienceProblem: SolarStellarFlareComparison

PrimaryActor:

Astronomer

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ScienceGoal:

Compare the atttributes of stellar and solar flares in order to determine the mechanism causing flares.

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DataSets:

SOHO, Yokhoh, EXOSAT, ROSAT, XMM, Chandra

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ProblemDescription:

Solar flares are well observed in the most wavebands, and stellar flares have been observed in the optical radio bands for over 35 years. UV and X-ray examinations of stellar flares began in the early 1980's [1]. X-ray observations of solar activity made with the Yohkoh satellite in the mid 1990's have uncovered a correlation between the peak temperature and X-ray flux of solar flares [2]. An analysis of the red and blue shifts of X-ray spectral lines can also indicate upflowing material that may contribute to the solar flare mechanism. Astonomers are now extrapolating the results of solar X-ray spectra to determine whether stellar flares display the same behaviour. Shibata et al have developed a "Hertzsprung-Russell-like Diagram" of temperature versus X-ray flux for solar and stellar flares, based on a model of magnetic reconnection [3].

More data analysis needs to be done to further understand the mechanisms behind solar and stellar flares. Although solar flares are now organized into catalogues such as the BATSE Solar Flare Server [4], stellar flares have not yet been catalogued. Finding stellar flare data involves time-consuming literature searches for times / locations of stellar flares, and then access to x-ray datasets covering those times and positions must be gained.

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CurrentSolution:

Currently, astronomers studying stellar flares must search the literature for position and time intervals of published flares; there is no stellar flare catalogue. Next, x-ray datasets (lightcurves, spectra, and redshift / blueshift information) covering the position and time intervals must be acquired from various institutions.

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VOSolution:

The VO can solve the first problem, lack of a stellar flare catalogue, by allowing astronomers to publish information about observed stellar flares into a stellar flare catalogue held in public MySpace . Next, solar and stellar flare datasets can be more easily examined and correlated access to thousands of X-ray datasets and flare models through one VO query interface.

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Iteration Breakdown:

• Astrogrid.Itn04SolarStellarFlareComparison - science workflow for case in Iteration 04
• Astrogrid.Itn06SolarStellarFlareComparison - science workflow for case in Iteration 06
• Astrogrid.Itn08SolarStellarFlareComparison - science workflow for case in Iteration 08

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KeyReferences:

[1] Pallavicini et al, AA. 228, 403-425 1990

[2] Feldman et al, ApJ, 451, L79-L81 1995

[3] Shibata et al, ApJ, 577, 422-432 2002

[4] Dennis et al, "Access to BATSE Solar Flare Data for the Solar Physics Community", NASA, http://umbra.nascom.nasa.gov/batse/batse_archive.html, Viewed 25/09/02

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GoodStyle: Please add comments below. This area should be used for refinement of the above document. If you want to ask questions or start a dialogue with the author, please use (or create) a topic in the Use Cases Forum.
Author: Once the refinements here and comments in the forum die down, perhaps you could rewrite the problem, incorporating the comments and refinements.

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