The Second APOKASC Catalog: The Empirical Approach

Marc H. Pinsonneault, Yvonne P. Elsworth, Jamie Tayar, Aldo Serenelli, Dennis Stello, Joel Zinn, Savita Mathur, Rafael A. Garcia, Jennifer A. Johnson, Saskia Hekker, Daniel Huber, Thomas Kallinger, Szabolcs Mészáros, Benoit Mosser, Keivan Stassun, Léo Girardi, Thaise S. Rodrigues, Victor Silva Aguirre, Deokkeun An, Sarbani BasuWilliam J. Chaplin, Enrico Corsaro, Katia Cunha, D. A. Garcia-Hernández, Jon Holtzman, Henrik Jönsson, Matthew Shetrone, Verne V. Smith, Jennifer S. Sobeck, Guy S. Stringfellow, Olga Zamora, Timothy C. Beers, J. G. Fernández-Trincado, Peter M. Frinchaboy, Fred R. Hearty, Christian Nitschelm

Research output: Contribution to journalArticlepeer-review

191 Scopus citations


We present a catalog of stellar properties for a large sample of 6676 evolved stars with Apache Point Observatory Galactic Evolution Experiment spectroscopic parameters and Kepler asteroseismic data analyzed using five independent techniques. Our data include evolutionary state, surface gravity, mean density, mass, radius, age, and the spectroscopic and asteroseismic measurements used to derive them. We employ a new empirical approach for combining asteroseismic measurements from different methods, calibrating the inferred stellar parameters, and estimating uncertainties. With high statistical significance, we find that asteroseismic parameters inferred from the different pipelines have systematic offsets that are not removed by accounting for differences in their solar reference values. We include theoretically motivated corrections to the large frequency spacing (Δν) scaling relation, and we calibrate the zero-point of the frequency of the maximum power (ν max) relation to be consistent with masses and radii for members of star clusters. For most targets, the parameters returned by different pipelines are in much better agreement than would be expected from the pipeline-predicted random errors, but 22% of them had at least one method not return a result and a much larger measurement dispersion. This supports the usage of multiple analysis techniques for asteroseismic stellar population studies. The measured dispersion in mass estimates for fundamental calibrators is consistent with our error model, which yields median random and systematic mass uncertainties for RGB stars of order 4%. Median random and systematic mass uncertainties are at the 9% and 8% level, respectively, for red clump stars.

Original languageEnglish (US)
Article number32
JournalAstrophysical Journal, Supplement Series
Issue number2
StatePublished - Sep 2018

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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