Sun-as-a-star Analyses of Various Solar Active Events Using H$\alpha$ Spectral Images Taken by SMART/SDDI

Abstract

Sun-as-a-star analyses, in which observational data is spatially integrated, are useful for interpreting stellar data. For future applications to stellar observations, we performed Sun-as-a-star analyses of H$\alpha$ spectra for various active events on the Sun, not only for flares and filament eruptions/surges on the solar disk, but also for eruptions of off limb prominences using H$\alpha$ spectral images taken by the Solar Magnetic Activity Research Telescope / Solar Dynamics Doppler Imager (SMART/SDDI) at Hida Observatory, Kyoto University. All the analyzed events show emission relative to the pre-event state and the changes in their H$\alpha$ equivalent widths are all on the orders of 10${}^{-4}$ Å. Sun-as-a-star H$\alpha$ spectra exhibit different features depending on the causes of the emission: (i) Flares show emission at the H$\alpha$ line center, together with red asymmetry and line broadening, as reported in a previous study. (ii) Filament eruptions with and without flares show emission near the H$\alpha$ line center, accompanied by blue-/red-shifted absorption. Notably, disappearance of dark filaments leads to the apparent enhancement of the H$\alpha$ line center emission. (iii) Eruptions of off limb prominences show blue-/red-shifted emission. These spectral features enable us to identify the active phenomena on Sun-like stars. We have also found that even the filament eruptions showing red-shifted absorptions in Sun-as-a-star H$\alpha$ spectra lead to coronal mass ejections (CMEs). This result suggests that even if the falling components of stellar filament eruptions are detected as red-shifted absorptions in H$\alpha$ spectra, such stellar filament eruptions may also develop into CMEs.

23 pages, 19 figures. Accepted for publication in The Astrophysical Journal

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Cited by in corpus (15)

• APO & SMARTS flare star campaign observations I. Blue wing asymmetries in chromospheric lines during mid M dwarf flares from simultaneous spectroscopic and photometric observation data
• Detection of a high-velocity prominence eruption leading to a CME associated with a superflare on the RS CVn-type star V1355 Orionis
• Stellar Coronal Mass Ejections
• A comparative study of two X2.2 and X9.3 solar flares observed with HARPS-N: Reconciling Sun-as-a-star spectroscopy and high-spatial resolution solar observations in the context of the solar-stellar connection
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• Reconstructing the XUV Spectra of Active Sun-like Stars Using Solar Scaling Relations with Magnetic Flux
• Spectral variations within solar flare ribbons
• Unified Relationship between Cold Plasma Ejections and Flare Energies Ranging from Solar Microflares to Giant Stellar Flares
• Synthesizing Sun-as-a-star flare spectra from high-resolution solar observations
• Spectroscopic observations of flares and superflares on AU Mic
• Do Young Suns Produce Frequent, Massive CMEs? Results from Five-year Dedicated Optical Observations of EK Draconis and V889 Hercules
• Discovery of multi-temperature coronal mass ejection signatures from a young solar analogue
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic III: Quiescent and Flaring Properties of the X-ray Spectra and Chromospheric lines
• Simulating stellar coronal rain and slingshot prominences
• Comparison of chromospheric diagnostics in a 3D model atmosphere: H$\alpha$ linewidth and mm continua