Multiplicity Systems as Metrics for Stellar Evolution Theory: Spectroscopic Eclipsing, Eclipsing and Unresolved Binaries

Binary stars serve as the Astrophysical laboratory in the extraction of stellar and orbital parameters and as calibration sites for stellar evolution theory. These systems come in three flavors, Spectroscopic Eclipsing, Eclipsing and Unresolved. Spectroscopic eclipsing binaries with complete orbital and stellar solutions from APOGEE’s overlap with Kepler (J.M.C. Cunningham et al. 2019) and TESS (J.M.C. Cunningham et al. 2022) are presented. Depending on the binary system, different methodologies are equipped, including both the Cross Correlation and Broadening Function methods of Radial Velocity extraction. Age estimates for the binary subsets are used to determine the degree of coevality of the systems (that is, the assumption that binary stars form at the same time). A unique, young eclipsing binary with a tertiary component, HD-54236, is also presented (J.M.C. Cunningham et al. 2020). In this case Gaia proper motion and age estimates established it having likely membership to a newly discovered stellar stream association, Theia-301 which has a common stellar population of six stars with Ab-Dor. When the age estimates of HD-54236 system are applied to AB-Dor-C, it’s controversial luminosity problem is litigated. Binary (and higher order multiplicity) systems may have such far reaching effects on stellar formation in terms of intermolecular cloud fragmentation and initial mass function that incomplete binary fraction estimates prevent true modeling of these foundational processes. The inauguration of a well constrained multiplicity system, complete with stellar and orbital solutions, age estimates and galactic motion vectors results in a more complete understanding of how all stars are born, live, and die. These insights have far-reaching foundational value at all Astrophysical scales from galactic to planetary formation.