Astronomical Cardiology: A Search For Heartbeat Stars Using <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mtext mathvariant="italic">Gaia</a:mtext> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mtext mathvariant="italic">TESS</c:mtext> </c:math>

Heartbeat stars are a subclass of binary stars with short periods, high eccentricities, and phase-folded light curves that resemble an electrocardiogram. We start from the 𝐺𝑎𝑖𝑎 catalogs of spectroscopic binaries and use 𝑇𝐸𝑆𝑆 photometry to identify 112 new heartbeat star systems. We fit their phase-folded light curves with an analytic model to measure their orbital periods, eccentricities, inclinations, and arguments of periastron. We then compare these orbital parameters to the 𝐺𝑎𝑖𝑎 spectroscopic orbital solution. Our periods and eccentricities are consistent with the 𝐺𝑎𝑖𝑎 solutions for 85 % of the single-line spectroscopic binaries but only 20 % of the double-line spectroscopic binaries. For the two double-line spectroscopic binary heartbeat stars with consistent orbits, we combine the 𝑇𝐸𝑆𝑆 phase-folded light curve and the 𝐺𝑎𝑖𝑎 velocity semi-amplitudes to measure the stellar masses and radii with 𝙿𝙷𝙾𝙴𝙱𝙴. In a statistical analysis of the HB population, we find that non-giant heartbeat stars have evolved off the main sequence and that their fractional abundance rises rapidly with effective temperature.