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SEGUE Stellar Parameter Pipeline (SSPP)
Introduction
SDSS/SEGUE stellar spectra are processed through the SEGUE Stellar Parameter Pipeline (SSPP), and three primary stellar parameters, effective temperature (Teff), surface gravity (log g), and metallicity ([Fe/H]) are reported for most stars in the temperature range 4000 - 10,000 K and with spectral S/N ratios exceeding 10/1. In that process, the line indices of various atomic and molecular lines are also measured. The detailed descriptions of the SSPP can be found in a series of papers (Lee et al. 2008a, Lee et al. 2008b, and Allende Prieto et al. 2008). The changes and improvements made on the SSPP since the DR7 are described in Smolinski et al. (2011). The following links highlight some important features, improvements, changes of the SSPP since the DR8.
Details
- List of Changes and Improvements Since DR8
- Temperature Estimate from InFred Flux Method (IRFM)
- Re-calibration of SSPP Parameters
- Line Index Measurements in SSPP
- Individual Methods Used in SSPP
- Flags in SSPP
- Decision Tree on Temperature, Gravity, and Metallicities
- SSPP Output Plots
- Comparisons of SSPP Parameters with High-resolution Analysis
- Comparisons of SSPP Parameters with Clusters
- Internal Consistency of Each Parameter in SSPP
- Caveats for SSPP Parameters
- Accessing SSPP Parameters
[α/Fe] Measurements
There is measurement of [α/Fe] ratio by the SSPP, and there is value added catalog for this in the DR9. A detailed description of the alpha measurement can be found in Lee et al. (2011).
Extinction Calculations
SSPP reports extinction values in the SDSS's ugriz filter system. The pipeline calculates these values by converting from standard extinction E(B-V) values (Schlegel, Finkbeiner, & Davis 1998), using the following conversions:
Extinction_u = 5.155*E(B-V)
Extinction_g = 3.793*E(B-V)
Extinction_r = 2.751*E(B-V)
Extinction_i = 2.086*E(B-V)
Extinction_z = 1.479*E(B-V)