Suppression of Hydrogen Emission in an X-class White-light Solar Flare
- Astrophysics Research Centre, Queen’s University Belfast, Northern Ireland (United Kingdom)
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, 2000 Colorado Avenue, Boulder, CO 80305 (United States)
- Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic)
We present unique NUV observations of a well-observed X-class flare from NOAA 12087 obtained at the Ondřejov Observatory. The flare shows a strong white-light continuum but no detectable emission in the higher Balmer and Lyman lines. Reuven Ramaty High-Energy Solar Spectroscopic Imager and Fermi observations indicate an extremely hard X-ray spectrum and γ -ray emission. We use the RADYN radiative hydrodynamic code to perform two types of simulations: one where an energy of 3 × 10{sup 11} erg cm{sup −2} s{sup −1} is deposited by an electron beam with a spectral index of ≈3, and a second where the same energy is applied directly to the photosphere. The combination of observations and simulations allows us to conclude that the white-light emission and the suppression or complete lack of hydrogen emission lines is best explained by a model where the dominant energy deposition layer is located in the lower layers of the solar atmosphere, rather than the chromosphere.
- OSTI ID:
- 22661330
- Journal Information:
- Astrophysical Journal, Vol. 837, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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