Detailed diagnostics of an X-ray flare in the single giant HR 9024

Abstract

We analyze a 96 ks Chandra/HETGS observation of the single G-type giant HR 9024. The high flux allows us to examine spectral line and continuum diagnostics at high temporal resolution, to derive plasma parameters. A time-dependent 1D hydrodynamic model of a loop with half-length $L=5\times 10^{11}$ cm ($\sim R_{\star }/2$), cross-section radius $r=4.3\times 10^{10}$ cm, with a heat pulse of 15 ks and $2\times 10^{11}$~erg cm${}^{-2}$ s${}^{-1}$ deposited at the loop footpoints, satisfactorily reproduces the observed evolution of temperature and emission measure, derived from the analysis of the strong continuum emission. For the first time we can compare predictions from the hydrodynamic model with single spectral features, other than with global spectral properties. We find that the model closely matches the observed line emission, especially for the hot ($\sim 10^8$ K) plasma emission of the FeXXV complex at $\sim 1.85$Å. The model loop has $L/R_{\star }\sim 1/2$ and aspect ratio $r/L\sim 0.1$ as typically derived for flares observed in active stellar coronae, suggesting that the underlying physics is the same for these very dynamic and extreme phenomena in stellar coronae independently on stellar parameters and evolutionary stage.

26 pages. Accepted for publication on the Astrophysical Journal

References in corpus (10)

• The Chandra High Energy Transmission Grating: Design, Fabrication, Ground Calibration and Five Years in Flight
• Bright X-ray flares in Orion young stars from COUP: evidence for star-disk magnetic fields?
• On the sizes of stellar X-ray coronae
• The Density of Coronal Plasma in Active Stellar Coronae
• Nonthermal Hard X-ray Emission and Iron Kalpha Emission from a Superflare on II Pegasi
• Modeling an X-ray Flare on Proxima Centauri: evidence of two flaring loop components and of two heating mechanisms at work
• Emission measure distribution in loops impulsively heated at the foot-points
• Six Large Coronal X-ray Flares Observed With Chandra
• Some Like it Hot: The X-Ray Emission of The Giant Star YY Mensae
• Evidence of the FIP effect in the coronae of late-type giants

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• Element abundances in X-ray emitting plasmas in stars
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