Modeling the corona and XUV emission from the Sun and Sun-like stars
Abstract
The evolution of the planetary atmosphere is significantly affected by the XUV emission from the host star. It is, however, impossible to directly measure the XUV spectrum of a given star because XUV photons suffer from significant interstellar extinction. In this presentation, we propose a model to predict the XUV emission from Sun-like stars, by extending the self-consistent solar coronal heating model. The simulations are performed for a range of loop lengths and magnetic filling factors at the stellar surface. With the solar parameters, our model reproduces the observed solar XUV spectrum below the Lyman edge, which validates the capability in predicting the XUV spectra of other Sun-like stars. The model also reproduces the observed nearly-linear relation between the unsigned magnetic flux and X-ray luminosity. From the simulation runs with various loop lengths and filling factors, we have found a scaling relation of logLEUV = 9.93 + 0.67logLX where LEUV and LX are the cgs-unit luminosity in the EUV (100 A < < 912 A) and X-ray (5 A < 100 A) ranges, respectively. By assuming a power-law relation between the Rossby number and magnetic filling factor, the widely known relation between the Rossby number and X-ray luminosity is also reproduced. This study provides the theoretical relation useful in estimating the hidden stellar EUV luminosity from X-ray observations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.P55D1960S