A study of weak molecular and atomic lines in the photospheric spectrum

Abstract

An attempt is made to detect the lines of Mg2aH and MgZaH in the photospheric spectrum, using calculated isotope shifts. From comparisons with the Mg24H lines of the zX-ZH transition in the (0, 0) band the ratios MgZS/Mg24 --0.12 • 0.04 and Mg26/Mg 24 = 0.12 4-0.02 are derived. These are essentially the same as the terrestrial ratios. The profile of one line of MgI confirms these values.The wavelengths of MgH and C2 lines, when corrected for the gravitational red shift, indicate that macroturbulent (or streaming) velocities die out near log TO =-1.0. Frem the equivalent widths of the MgH lines a rotational temperature of 5132 • K is obtained and compared to predictions from various model atmospheres. The band oscillator strength is found to be 0.024 • 0.002, in serious disagreement with the single laboratory determination.The profiles of MgH, C2, CN and some weak atomic lines are used to derive the variation of the radial component of microturbulence with optical depth, on the assumption of streaming velocities of 2.5-3.0 km/sec. A slow increase with increasing height in the photosphere is found, over the range --1.5 < logz0< 0.2.The center-limb variation of the equivalent widths of MgH and Ca lines for a wholly inhomogeneous model is found to be the same as for a model which is homogeneous above log T0 ----1.0. With such a model as the latter, the center-limb variation of the profiles of the selected molecular and atomic lines is moderately-well reproduced by an anisotropic microturbulent velocity with a tangential component of 3 km/sec which seems to be constant with height over the range considered.

Hybrid Detection Algorithm and Study on the Quantity and Brightness Evolution Characteristics of Photospheric Bright Point Groups

“…GST is equipped with adaptive optics, which can correct atmospheric distortion in real time so that the observed image effect is evident. High-contrast BPs can be observed in the G-band (4300 Å) continuum and the TiO (7058 Å) spectral line (Mallia 1968;Liu et al 2014). We selected the TiO-band observation data from BBSO, with observation dates of 2016 June 22, from 16:25:16 UT to 22:24:41 UT (target: NOAA 12556), and 2020 July 30, from 16:50:09 UT to 22:17:18 UT (target: quiet-Sun bipolar region), which provided continuous high-quality, high-resolution images of regions near the center of the solar disk.…”

“…When observing the photosphere using CH and CN molecular lines and certain spectral lines, the absorption of these lines weakens in regions where a strong magnetic field is concentrated. This allows more photons from the continuous spectrum to escape from the deep photosphere through the flux tube, leading to an increased brightness of the G-band CH line or TiO band, and ultimately forming BPs (Mallia 1968;Kiselman et al 2000;Rutten et al 2001;Schüssler et al 2003). It shows that the activity of BPs is not static, but a dynamic process.…”

Research on the quantity and brightness evolution characteristics of Photospheric Bright Points groups

“…Generally, high-contrast BPs can be observed in the G-band (4300 Å) continuum. In addition to the G-band, the spectral line TiO(7058 Å) is also used to observe BPs (Mallia 1968;Liu et al 2014). TiO (7058 Å) has A longer wavelength than the G-band.…”

“…When the CH and CN molecular lines and some spectral lines are used to observe the photosphere, the absorption of these absorption lines becomes weak where the strong magnetic field is concentrated, and more photons in the continuous spectrum are allowed to escape from the deep photosphere through the flux tube, which makes the Gband CH line or TiO band brighter and forms BPs. It shows that the activity of BPs is not static, but a dynamic process (Mallia 1968;M. et al 2003;Rutten et al 2001;Kiselman et al 2000).…”