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Version 3, Jan 2025
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Overview
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This tool is intended to aid in the identification of stellar spectral lines in an astronomical spectrum by presenting a list of spectral lines within a specified wavelength range along with information aiding in the identification of the element or elements, in the case of a blended line, most likely responsible for the observed spectral feature. Information presented in this identification include the element/ion, its center wavelength, temperature of peak intensity, number abundance, temperature/abundance scaled relative intensity, delta wavelength, and delta temperature.
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1. Temperature of Peak Intensity - The temperature, determined by the Boltzmann and Saha equations, for whch the intensity of the spectral lines is greatest.
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2. Number Abundance - The abundance of the element in the solar photosphere on a lograthmic scale in which the hrdorgen log abundance has a value of 12.
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3. Temperature/Abundance Scaled Relative Intensity - A dimensionless number ranging from 0 to 3635 indicating the strength of the spectral line relative to other spectral lines. This value accounts for the intensity at the specified temperature as determined by the Boltzmann and Saha equations and the abundance of the element in the solra photosphere.
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4. Delta Wavelength - The difference in wavelength of a spectral line and the input center wavelength of the search range. Elements/ions with small delta wavelengths are more likely to be responsible for the observed spectral feature than those with larger delta wavelengths, but this has to be considered along with the the scaled relative intensity.
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5. Delta Temperature - The difference between the input temperature and the temperature of maximum intensity for that element.ion. Element/ions with smaller delta temperatures are more likely to be responsible for the observed spectral feature than those with larger delta temperature, but this has to considered along with the scaled relative intensity.
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Limitations Of This Tool:
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1. This tool is intended to be used to analyze stellar spectra as it uses information modeled on a typical stellar photosphere, and the solar photosphere in particular.
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2. Modeling of number densities used in the Boltzmann/Saha equations is based on the solar photosphere and scaled only for temperature. As such, photospheric pressure differences as exhibited in different spectral classes for a given spectral type are not accounted for here.
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3. Element and their ions used for this analysis are the 20 most abundant elements by number in the solar photosphere. Future versions of this toll will likely include additional elements.
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4. Lines for a particular ionization stage of an element is presented only if a) that ion exists (i.e., there is no H II or He III), b) there are lines within the visible range from that element/ion, or c) the peak Boltzmann/Saha intensity is at a temperature greater than 55,000 K.
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5. Molecular lines/bands are not included within this tool for line identification
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Three Tools Are Provided:
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1. ID By Wavelength - This tool presents the spectral lines within a specified wavelength range and for a star of a specified temperature.
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2. Element Lines - This tool presents the spectral lines for a specified element and ionization stage across the visible spectrum
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3. Elements By Intensity - This tool presents the spectral lines for all elements and ions across the visible spectrum for a specified temperature and minimum intensity
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S. Donnell, Kiowa Creek Observatory
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Peyton, Colorado USA
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donnellsp@gmail.com
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