Ca II H & K Spectra From The National Solar Observatory
Abstract
When the Sun is observed as a star (i.e., spatially integrated full disk) the cores of the chronospheric H and K resonance lines of singly ionized calcium show the greatest cycle variability (up to 40% peak-to-peak) accessible from the ground. Synoptic archives are available at monthly intervals from 1974 (Kitt Peak) and for K only at almost a daily cadence from 1984 (Sacramento Peak). We discuss these time series and compare them with, for example, sunspot numbers and magnetic fields. Less frequent are center disk observations in which the activity cycle is found to be absent, implying the quiet basal atmosphere is constant and not, say, heated by cycle magnetic activity. New, near daily, spatially integrated full disk solar data from the SOLIS Integrated Sunlight Spectrometer (ISS)agree well with the older work. We now propose to produce calibrated (Houtgast 1970; Solar Phys 15, 273, high points: 387.5, 395.3, and 402.0 nm), low dispersion full disk spectra that may be directly compared with that from solar-type stars.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2008
- Bibcode:
- 2008AGUSMSP53B..04L
- Keywords:
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- 7500 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7507 Chromosphere;
- 7536 Solar activity cycle (2162);
- 7537 Solar and stellar variability (1650);
- 7594 Instruments and techniques