Solving a supersolar+subsolar eclipsing binary with serendipitous photometry & spectroscopy

Eclipsing binary stars (EBs) are fundamental tools for understanding stellar evolution. Precise masses and radii can be measured for EBs, but these measurements typically require densely sampled light curves and radial velocities that identify the system’s orbital period, velocity amplitude, and the morphology of the eclipse events. Historically, these observations have been time and resource intensive, but large scale photometric and spectroscopic surveys provide new opportunities to detect and characterize EBs with survey data alone. To demonstrate this capability, we calculated physical and orbital properties for 2M17091769+3127589, a 5.87 day binary. Using the ellc package to model the system’s ASAS-SN light curve, we extracted radii and surface brightnesses of the system’s components. Extracting radial velocities for each component from a series of 6 SDSS/APOGEE spectra, we measured the system’s mass ratio before using The Joker to fit the full orbit. Our analysis indicates that 2M17091769+3127589 has a high mass ratio (m1/m2 = 5.68) and a supersolar primary (Mprim ~ 1.25 Msolar) with strong out-of-eclipse variations due to ellipsoidal distortions and/or spot effects. We report our full characterization of this system, and prospects for similar analyses using survey data to measure precise physical and orbital properties for EBs.