Optical Spectra of Stars

SEGUE Stellar Parameter Pipeline (SSPP)


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, Smolinski et al. 2011, and Rockosi et al. 2022).

Our tutorials include how to get started using SEGUE data and a more in-depth description of how to access SEGUE data with CASJobs.

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)