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The corona and upper transition region of ε Eridani
- Source :
- Monthly Notices of the Royal Astronomical Society. 385:1691-1708
- Publication Year :
- 2008
- Publisher :
- Oxford University Press (OUP), 2008.
-
Abstract
- We present analyses of observations of epsilon Eridani (K2 V) made with the Low Energy Transmission Grating Spectrometer on Chandra and the Extreme Ultraviolet Explorer, supplemented by observations made with the Space Telescope Imaging Spectrograph, the Far Ultraviolet Spectroscopic Explorer and the Reflection Grating Spectrometer on XMM-Newton. The observed emission lines are used to find relative element abundances, to place limits on the electron densities and pressures and to determine the mean apparent emission measure distribution. As in the previous paper by Sim & Jordan (2003a), the mean emitting area as a function of the electron temperature is derived by comparisons with a theoretical emission measure distribution found from energy balance arguments. The final model has a coronal temperature of 3.4 x 10^6 K, an electron pressure of 1.3 x 10^16 cm^-3 K at T_e = 2 x 10^5 K and an area filling factor of 0.14 at 3.2 x 10^5 K. We discuss a number of issues concerning the atomic data currently available. Our analyses are based mainly on the latest version of CHIANTI (v5.2). We conclude that the Ne/O relative abundance is 0.30, larger than that recommended from solar studies, and that there is no convincing evidence for enhanced coronal abundances of elements with low first ionization potentials.
- Subjects :
- Physics
Spectrometer
Filling factor
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Electron
Space and Planetary Science
Ionization
Extreme ultraviolet
Astrophysics::Solar and Stellar Astrophysics
Electron temperature
Emission spectrum
Astrophysics::Galaxy Astrophysics
Space Telescope Imaging Spectrograph
Subjects
Details
- ISSN :
- 13652966 and 00358711
- Volume :
- 385
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi...........770bb149254316725f19c0cb7d0da460
- Full Text :
- https://doi.org/10.1111/j.1365-2966.2007.12757.x