Improvements in the Determination of ISS Ca ii K Parameters
- 128 Downloads
Measurements of the ionized Ca ii K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a ground-based proxy to model the solar ultraviolet flux variation that may influence the Earth’s climate. Full disk images of the Sun in Ca ii K have been available from various observatories for more than 100 years and latter synoptic Sun-as-a-star observations in Ca ii K began in the early 1970s. One of these instruments, the Integrated Sunlight Spectrometer (ISS) has been in operation at Kitt Peak (Arizona) since late 2006. The ISS takes daily observations of solar spectra in nine spectra bands, including the Ca ii K and H lines. We describe recent improvements in data reduction of Ca ii K observations, and present time variations of nine parameters derived from the profile of this spectral line.
KeywordsSolar activity, observations, data analysis Chromosphere, active
- Keil, S.L., Henry, T.W., Fleck, B.: 1998, NSO/AFRL/Sac peak K-line monitoring program. In: Balasubramaniam, K.S., Harvey, J., Rabin, D. (eds.) Synoptic Solar Physics CS-140, 301 – 309. Google Scholar
- Keller, C.U., Harvey, J.W., Giampapa, M.S.: 2003a, SOLIS: an innovative suite of synoptic instruments. In: Keil, S.L., Avakyan, S.V. (eds.) Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 4853, 194 – 204. Google Scholar
- Keller, C.U., Harvey, J.W., The Solis Team: 2003b, The SOLIS vector-spectromagnetograph. In: Trujillo-Bueno, J., Sanchez Almeida, J. (eds.) Astronomical Society of the Pacific Conference Series, 307, 13 – 22. Google Scholar
- Lenz, L.F., Reiners, A., Kürster, M.: 2010, A search for star – planet interactions in chromospheric lines. ArXiv:1012.1720.
- Pierce, A.K., Breckinridge, J.B.: 1974, The Kitt Peak table of photographic solar spectrum wavelengths. KPNO contribution 559. Google Scholar
- Wallace, L., Hinkle, K., Livingston, W.: 2007, An atlas of the spectrum of the Solar photosphere from 13 500 to 33 980 cm −1 (2942 to 7405 Å). Google Scholar