HR: 16:35h
AN: SH14B-03    [Abstracts]
TI: Thermally peeling the Corona
AU: * Kashyap, V L
EM: vkashyap@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, United States
AB: The outer atmospheres of most low-mass stars, including the Sun, are composed of very hot plasma (1-50 MK) which is organized in spatially and thermally complex structures. A proper determination of these structures is necessary to decide the energetics of coronae, to establish their compositions, and to distinguish between different physical processes that may operate on them. The challenge of solar and stellar astrophysicists is thus to determine the temperature structure reliably, i.e., to establish how much of the observed intensity arises at what temperature. The data here are comprised of spectral lines from highly ionized species of elements such as Fe, Ne, O, etc. By measuring the intensities in specific lines, and calculating their emissivities from known atomic data, we can infer the shape of the underlying emission measure distribution. However, straightforward inversion solutions are subject to high-frequency instability, and we must carry out forward-fits to carry out the inference. We describe some of the challenges posed by this problem and discuss different methods of solutions, primarily based on a Markov-Chain Monte Carlo method.
DE: 0520 Data analysis: algorithms and implementation
DE: 3255 Spectral analysis (3205, 3280)
DE: 7509 Corona
DE: 7554 X-rays, gamma rays, and neutrinos
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting