The solar lithium abundance

A detailed observational study of the solar photospheric lithium feature has been carried out with emphasis on center-limb observations, continuum location, possible effects of telluric lines, effects of blending by atomic and molecular lines, and decomposition of the solar spectrum around λ6707 Å.     

The solar niobium abundance

The solar Nb abundance is derived from five Nb i and ten Nb ii lines in the photospheric spectrum. Equivalent widths are obtained from measurements on spectra recorded at Kitt Peak National Observatory. Synthetic spectrum calculations gave abundances of 2.23 and 2.08 from neutral and ionized lines respectively in the logarithmic A _H = 12.00 scale. This gives an average abundance value of A _Nb = 2.13 ± 0.10.     

The solar hafnium abundance

The solar Hf abundance is determined using nine Hf ii lines in the photospheric spectrum. The transition probabilities were obtained from lifetime measurements performed by the beam-foil technique. The abundance derived from synthetic spectrum calculations is A(Hf) = 0.88 ± 0.08 in the logarithmic A(H) = 12.00 scale.     

The solar manganese abundance

A preliminary solar Mn abundance of logN(Mn) = 5.41 (logN(H) = 12.00) is derived on the basis of fitting theoretical line profiles which include hyperfine structure (HFS) broadening to the profiles of the 5394.7, 5432.6, and 5537.8 lines of Mn observed at the center of the solar disk with the double-pass spectrograph of the McMath solar telescope at Kitt Peak. Both the Mn abundance and the collisional damping constant were varied during the fitting procedure in order to minimize the rms deviation between the observed and computed profiles.Visiting Astronomer, 1970, Kitt Peak National Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract to the National Science Foundation.     

The solar abundance of tungsten

Recent measurements of Wi oscillator strengths (Obbarius and Kock, 1982) lead to a solar photospheric abundance of tungsten, log _W = 1.06 ± 0.15 on the scale log _H = 12. The solar W/Si abundance ratio, 0.32 W atoms/10⁶ Si, coincides with that found in carbonaceous chrondrites. Implications for solar-system r-processes abundances are pointed out.     

The solar abundance of titanium

A solar titanium abundance has been derived from measurements of eight selected very weak lines.     

The solar abundance of gold

From 13 scans obtained with a double-band pass spectrograph at the Snow telescope at Mount Wilson, interpreted by the method of spectral synthesis, the abundance of gold turns out to be log [N(Au)/N(H)] + 12 = 0.70, assuming loggf = – 0.57.     

The solar abundance of thulium

The solar spectrum contains one relatively unblended line λ 3131.258 Tm ii which yields a thulium abundance of log N(Tm)/N(H) + 12 = {Tm} = 0.80 ± 0.10, with the Corliss and Bozman f-value. A recent beam-foil experiment suggests that the thulium abundance may be reduced to {Tm} = 0.30.     

The solar abundance of germanium

The solar abundance of germanium, deduced from two relatively unblended Ge i lines, λ3039.06 and λ3269.50 is found to be log N(Ge) = 3.50 ± 0.05 on the scale log N(H) = 12.00 in good agreement with Cameron's recent solar system abundance logN(Ge) = 3.56 (on assumption log N(Si) = 7.50).     

The solar photospheric abundance of zirconium

Zirconium (Zr), together with strontium and yttrium, is an important element in the understanding of the Galactic nucleosynthesis. In fact, the triad Sr‐Y‐Zr constitutes the first peak of s‐process elements. Despite its general relevance not many studies of the solar abundance of Zr were conducted. We derive the zirconium abundance in the solar photosphere with the same CO⁵BOLD hydrodynamical model of the solar atmosphere that we previously used to investigate the abundances of C‐N‐O. We review the zirconium lines available in the observed solar spectra and select a sample of lines to determine the zirconium abundance, considering lines of neutral and singly ionised zirconium. We apply different line profile fitting strategies for a reliable analysis of Zr lines that are blended by lines of other elements. The abundance obtained from lines of neutral zirconium is very uncertain because these lines are commonly blended and weak in the solar spectrum. However, we believe that some lines of ionised zirconium are reliable abundance indicators. Restricting the set to Zr II lines, from the CO⁵BOLD 3D model atmosphere we derive A (Zr) = 2.62 ± 0.06, where the quoted error is the RMS line‐to‐line scatter (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The solar photospheric abundance of iron

A new value of the solar photospheric abundance of iron, independent of line-shape parameters, is derived. Our analysis is based on a study of 40 weak infrared lines (0.85<λ<2.5 μ) for which theoretical oscillator strengths (calculated with configuration interactions taken into account) have recently been computed by Kurucz (1974). The abundance obtained, A _Fe = 7.57±0.11 (in the usual scale where log N _H = 12.00) is in agreement with the ‘high’ solar values recently reported in the literature and with the meteoritic abundance.     

The solar abundance of thorium and lead

Two new Th ii lines have been identified in the spectrum of the solar photosphere. The abundance derived from these lines together with the previously known Th ii line at 4019 Å, is log _Th = 0.85 ± 0.20 in the log _H = 12.00 scale. Analysis of three Pb i lines in the photospheric spectrum resulted in an abundance of log _pb = 1.90 ± 0.10. The solar Th/Pb ratio is: _Th/ _Pb = 0.09 _-0.005 ^0.09 .     

The potassium abundance in the solar photosphere

High precision center-limb spectrograms of the K i resonance doublet line at λ 7699 Å were used to study the line formation and to determine the abundance of potassium in the solar atmosphere. The LTE assumption is not valid for these lines. Synthetic profiles computed in NLTE reproduce very well the observed center-limb line behaviour and yield log? _K = 5.14±0.10 for the solar abundance of potassium (on the scale of log? _H = 12 for Hydrogen).     

The abundance of cadmium in the solar atmosphere

The solar spectrum at 3261 Å has been studied using the spectrograph at the Oslo Solar Observatory. From analysis of this wavelength region and recent results at 5085 Å, a solar cadmium abundance log N _Cd = 1.86 ± 0.15 is obtained.     

Helium abundance in the solar wind

Observations of hydrogen and helium ions in the solar wind have been carried out by the Goddard Space Flight Center - University of Maryland plasma instrument on Explorer 34. These ions are completely separated by means of electrostatic and magnetic fields. The average value of the ratio of number densities is 0.051 ± .02, derived from over 3000 h of measurement. Variations about this value from about 0.01 up to greater than 0.15 occur, and there are more high values than can be explained by random variation. A tentative association with some geomagnetic storms is suggested. The above value of abundance, assuming that plasma emitted in the ecliptic plane is a fair sample of the output of the sun, combined with other recent work by other methods indicate that the solar abundance may be about half the previously quoted estimates of approximately 0.1.     

The solar abundance of nickel from photospheric [Niii] lines

The detailed study of the possible presence of four [Niii] lines in solar absorption leads to an abundanceA _ni = logN _ni = 6.30±0.30 (in the usual scale where logN _H = 12.00), in agreement with the coronal and meteoritic values.On leave from Institut d'Astrophysique, Université de Liège.