SP_ACE computes stellar parameters (gravity, temperature) and element
abundances from optical stellar spectra (`sample spectrum`_). It employs
1D stellar atmosphere models in Local Thermodynamic Equilibrium (LTE).
The present service does not offer all the options available for SP_Ace
as documented in `the tutorial`_. All options are available if running
SP_Ace locally (cf. `download page`_).
This service exposes an updated version containing some bug fixes with
respect to the one described in the paper.
.. _the tutorial: http://dc.zah.uni-heidelberg.de/sp_ace/q/dist/static/tutorial.pdf
.. _download page: http://dc.zah.uni-heidelberg.de/sp_ace/q/dist/static
.. _sample spectrum: http://dc.zah.uni-heidelberg.de/sp_ace/q/c/static/fast_spectrum.txtSP_ACE spectral analysis toolOKAn upload of the form 'spectrum,URL'; the input for this parameter is then taken from URL, which may be param:name for pulling the content from the inline upload name. Purpose of the upload: ASCII file with two columns: wavelength (in Angstrom) and continuum normalized flux. The spectrum must be radial velocity corrected (wavelengths in rest frame). The spectral resolution power should be between 2000 and 20000. SP_Ace handles spectra in the stellar parameters intervals Teff=[3600,7400]K, logg=[0.2,5.0], [M/H]=[-2.4,0.4]dex.Starting value for estimation of FWHM of the instrument line profile.Give up to five wavelength intervals you want to analyze, starting from the lowest. Intervals not covered by the library will be ignored. The default setting is the range of wavelenghts currently processed by the software.Force solver to assume this temperature. Leave empty to let SP_Ace estimate this parameter.Force solver to assume this gravity. Leave empty to let SP_Ace estimate this parameter.Force solver to assume this signal to noise ratio on every pixel. Suggestion: Leave empty to let SP_Ace to estimate this parameter pixel-by-pixel.Provide an estimation of the object's radial velocity in case the spectrum is not RV-corrected.Make SP_Ace estimate errors (this increases runtime significantly).If selected, the output will only contain two abundances: 'alphas' and 'metals', which are the estimation of the abundances of alpha-process elements and non-alpha-process elements as if they were one element. Hint: This option is mostly useful with low-resolution (R ~ 2000) spectra. See the tutorial for more details.Process the spectrum with the normalization provided by the user? This option switches off the internal re-normalization done by SP_Ace. Suggestion: Do not set unless you are absolutely sure that your normalization is right.This parameter determines the flexibility of the curve used to fit the continuum during the re-normalization of the spectrum. The higher the number the more rigid the curve is (see discussion in the tutorial and in Sec.7.4 of the paper). Suggestion: leave the default value unless you know very well what you are doing.Switch on the loop that iteratively derives stellar parameters (Teff, log g, [M/H]) and chemical abundances. Suggestion: do not set (see Sec. 8.5.1 of the paper). If your spectrum has low resolution (R ~ 2000), see discussion in the tutorial.File format requested for output.Maximum number of records returned. Pass 0 to retrieve service parameters.Exhaustiveness of column selection. VERB=1 only returns the most important columns, VERB=2 selects the columns deemed useful to the average user, VERB=3 returns a table with all available columns.Element symbolElement abundance, logarithm of particle number relative to 1e12 H particles.Lower limit of 68% confidence interval of element abundanceUpper limit of 68% confidence interval of element abundanceNumber of lines evaluated for this element.Effective Temperature of the best-fit modelled spectrum.Lower limit of 68% confidence interval of Effective TemperatureUpper limit of 68% confidence interval of Effective TemperatureLog of gravity of the best-fit modelled spectrum.Lower limit of 68% confidence interval of Log of gravityUpper limit of 68% confidence interval of Log of gravityMetallicity of the best-fit modelled spectrum.Lower limit of 68% confidence interval of MetallicityUpper limit of 68% confidence interval of Metallicity0 if solution converged, otherwise an error flag (see note or table 1 in the tutorial).Empirical adjustment for RV (obtained by optimizing line overlap).A posteriori full width half maximum of the instrument profile.Estimated signal to noise ratio of incoming spectrum.χ² between incoming and modelled spectrum.