Sun-as-a-Star Spectral Line Variability in the 300–2390 nm Wavelength Range

Autor: Sergey V. Marchenko, Antje Ludewig, Serena Criscuoli, Khaled Al Moulla, Debi P. Choudhary, Matthew T. DeLand, Greg Kopp, Erwin Loots, Emiel van der Plas, Pepijn Veefkind
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: The Astrophysical Journal, Vol 977, Iss 1, p 33 (2024)
Druh dokumentu: article
ISSN: 1538-4357
19899726
DOI: 10.3847/1538-4357/ad888f
Popis: Combining the near-daily Ozone Monitoring Instrument (OMI) and Tropospheric Monitoring Instrument (TROPOMI) measurements of solar spectra, we construct line indices (line-core to line-flanks ratios) for various transitions (mainly Fe i ) in the 300–2390 nm spectral domain. The indices are supplemented by the wavelength-binned fluxes from OMI and Total and Spectral Solar Irradiance Sensor (TSIS-1). To study the short-term (solar-rotational) patterns, we normalize the indices and fluxes to the minimum-activity epoch, then de-trend them with 81 day running means. Comparisons of the de-trended TSIS-1 and OMI fluxes with the NASA-NOAA-LASP SSI (NNLSSI1) model show excellent agreement, to (0.5–2.2) × 10 ^−4 in the normalized and de-trended data. The data are subjected to a multiregression analysis against quantities representing the facular brightening and the sunspot darkening. The de-trended line indices and average fluxes show different sensitivities to these two solar magnetic-activity manifestations, with the fluxes being far more susceptible to the sunspot component. The de-trended line indices experience a rapid drop of activity levels towards longer wavelengths, albeit with a large rebound in the short-wave infrared (SWIR) domain that is caused by the ubiquitous, temperature-sensitive CO transitions. The wavelength-dependent activity also falls, however much slower, in the de-trended average fluxes. Qualitatively similar behavior is captured by semiempirical models.
Databáze: Directory of Open Access Journals
Externí odkaz: