The center-to-limb wavelength shift of a number of Fraunhofer lines

Lopresto, James C.; Pierce, A. Keith

doi:10.1007/bf00154033

Cited by 5 publications

(1 citation statement)

References 17 publications

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“…According to several studies (e.g. Lopresto & Pierce, 1985) the lines forming high at the atmosphere (near the temperature minimum, as our Ba ii line) have a very little convective blue shift. The above cited work does not provide information about the Ba ii 4554 Å line, however for lines formed at similar heights (Fe i 3767 Å, Na i 5896 Å, K i 7699 Å), the remaining blueshift is around 60 m s −1 .…”

Section: Calculation Of Velocity and Intensity Variations From Ba IIsupporting

confidence: 59%

Properties of convective motions in facular regions

Костик

Khomenko

2012

A&A

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Aims. We study the properties of solar granulation in a facular region from the photosphere up to the lower chromosphere. Our aim is to investigate the dependence of granular structure on magnetic field strength. Methods. We used observations obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife) using two different instruments: the Triple Etalon SOlar Spectrometer (TESOS) to measure velocity and intensity variations along the photosphere in the Ba ii 4554 Å line; and, simultaneously, the Tenerife Infrared Polarimeter (TIP-II) to the measure Stokes parameters and the magnetic field strength at the lower photosphere in the Fe i 1.56 μm lines. Results. We find that the convective velocities of granules in the facular area decrease with magnetic field while the convective velocities of intergranular lanes increase with the field strength. Similar to the quiet areas, there is a contrast and velocity sign reversal taking place in the middle photosphere. The reversal heights depend on the magnetic field strength and are, on average, about 100 km higher than in the quiet regions. The correlation between convective velocity and intensity decreases with magnetic field at the bottom photosphere, but increases in the upper photosphere. The contrast of intergranular lanes observed close to the disk center is almost independent of the magnetic field strength. Conclusions. The strong magnetic field of the facular area seems to stabilize the convection and to promote more effective energy transfer in the upper layers of the solar atmosphere, since the convective elements reach greater heights.

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Section: Calculation Of Velocity and Intensity Variations From Ba IIsupporting

confidence: 59%

Properties of convective motions in facular regions

Костик

Khomenko

2012

A&A

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The observed limb effect in Fraunhofer lines, I

Pierce

1991

Sol Phys

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The absolute limb effect is presented for FeI lines 23767 and 23969; for five Til lines ofmultiplet 42 near 24535 and one Till line at 24534; two lines of MgI, 24571 and 25172; two lines of Ba~i at 25854 and 26497. The scattered light of the McMath solar telescope is illustrated by several figures but not applied to the limb-effect observations. It is suggested that the supergravity shift at the limb is the result of scattering of the atoms in anisotropic velocity field.

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