SOLAR CYCLE VARIATION IN SUN-AS-A-STAR Ca II 854.2 nm BISECTORS

Journal Article · Mon Aug 01 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/736/2/114· OSTI ID:21578251

Pietarila, A; Livingston, W ^[1]

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1. National Solar Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

The bisector of the strong chromospheric Ca II 854.2 nm line has an inverse-C shape, the cause of which is not yet fully understood. We show that the amplitude of the bisector in Sun-as-a-star observations exhibits a solar cycle variation with smaller amplitudes during highest activity. The line core intensity is lower during solar minima while the part of the bisector most sensitive to the line core shows no systematic change with activity. Our results support the use of Ca II 854.2 nm bisectors in studying the relationship between convection and magnetic fields, not only in the Sun but in other stars as well.

• OSTI ID: 21578251
• Journal Information: Astrophysical Journal, Vol. 736, Issue 2; Other Information: DOI: 10.1088/0004-637X/736/2/114; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CALCIUM
CHROMOSPHERE
CONVECTION
MAGNETIC FIELDS
SOLAR CYCLE
VARIATIONS
ALKALINE EARTH METALS
ATMOSPHERES
ELEMENTS
ENERGY TRANSFER
HEAT TRANSFER
MASS TRANSFER
METALS
SOLAR ATMOSPHERE
STELLAR ATMOSPHERES