HEARTBEAT STARS ARE AN EMERGING CLASS OF ECCENTRIC (E>0.2) SHORT-PERIOD ELLIPSOIDAL VARIABLES THAT UNDERGO STRONG TIDAL INTERACTIONS NEAR ORBITAL PERIASTRON. IN THE KEPLER DATA WE HAVE IDENTIFIED 173 HEARTBEAT STARS %20 OF WHICH PULSATE WITH TIDALLY EXCITED MODES: STELLAR OSCILLATION MODES THAT ARE EXCITED TO OBSERVABLE AMPLITUDES (>10 PPM) BY THE TIDAL FORCING OF THE COMPANION STAR. WE HAVE OBTAINED 6 OR MORE FOLLOW-UP SPECTRA FOR 31 KEPLER HEARTBEAT STARS WITH TIDALLY INDUCED PULSATIONS MOST OF WHICH WE OBTAINED WITH THE KECK TELESCOPE MAUNA KEA AND THE 4-M MAYAL TELESCOPE KITT PEAK NATIONAL OBSERVATORY. USING THE COMBINATION OF KEPLER LIGHT CURVES AND SPECTRA (AND DISTANCES FROM GAIA ASTROMETRY ONCE AVAILABLE) WE WILL PRODUCE BINARY STAR MODELS FOR ALL THE HEARTBEAT STARS IN OUR SAMPLE BY APPLYING A COMBINATION OF PHOEBE A BINARY STAR MODELING CODE; EMCEE AN AFINE INVARIANT VERSION OF MARKOV CHAIN MONTE CARLO METHODS; AND OUR OWN CODES WHICH FIT DOPPLER BOOSTING AND TIDALLY INDUCED PULSATIONS. THESE MODELS WILL PROVIDE ACCURATE FUNDAMENTAL ORBITAL AND PULSATIONAL PARAMETERS WHICH WE WILL THEN USE TO PURSUE THE TWO AIMS OF THIS PROPOSAL. OUR FIRST AIM IS TO DETERMINE ORBITAL CIRCULARIZATION RATES DUE TO TIDALLY INDUCED PULSATIONS. IT IS PREDICTED THAT THE PRESENCE OF TIDALLY EXCITED MODES WILL CAUSE AN INCREASE IN THE RATE OF ORBITAL CIRCULARIZATION. BY ANALYZING THE MODE ENERGIES OF THE TIDALLY EXCITED MODES USING PULSATION MODELS (WITH THE BINARY STAR PARAMETERS AS INPUTS) WE CAN DETERMINE THE CIRCULARIZATION RATES OF ALL THE HEARTBEAT STARS IN OUR SAMPLE. THE RESULTS WILL PROVIDE KEY INFORMATION ON THE LINK BETWEEN TIDALLY INDUCED PULSATIONS AND ORBITAL CIRCULARIZATION APPLICABLE TO BOTH BINARY STARS AND PLANETS. OUR SECOND AIM IS TO UNDERSTAND THE IMPACT OF THREE BODY DYNAMICS IN FORMING TIGHT BINARIES AND SHORT PERIOD PLANETS. APPROXIMATELY 96% OF TIGHT (P<3 D) BINARIES HAVE BEEN OBSERVED TO CONTAIN TERTIARY COMPONENTS. HEARTBEAT STARS ARE UNDERGOING HIGH ECCENTRICITY MIGRATION AND ARE BELIEVED TO BE THE PROGENITORS OF TIGHT BINARIES. WE THUS EXPECT THAT THE MAJORITY OF HEARTBEAT STARS WILL ALSO HAVE TERTIARY COMPONENTS. TO EXPLORE THIS POSSIBILITY WE WILL APPLY A RANGE OF COMPLEMENTARY TECHNIQUES TO SEARCH FOR THIRD BODIES INCLUDING: LOOKING FOR EVIDENCE IN THE SPECTRA USING THREE DIMENSIONAL CROSS CORRELATION; LOOKING FOR LIGHT TRAVEL TIME VARIATIONS BY MEASURING THE ARRIVAL TIME OF THE PERIASTRON VARIATION; AND LOOKING FOR RAPID (RELATIVE TO THE THEORETICAL RATE) AND NON-CONTINUOUS APSIDAL MOTION WHICH IS INDICATIVE OF A THIRD COMPONENT. WE HAVE ALREADY DETECTED THE PRESENCE OF THIRD BODIES IN THE TWO OBJECTS IN OUR SAMPLE WITH ECLIPSES BY CONSIDERING THE ECLIPSE TIMING VARIATIONS (ONE DIRECTLY AND ONE THROUGH THE PRESENCE OF EXTREME APSIDAL MOTION). WE HAVE ALSO APPLIED FOR FURTHER KECK TELESCOPE TIME; IF SUCCESSFUL THE RADIAL VELOCITY TEMPORAL BASELINE WILL BE LONG ENOUGH TO SEARCH FOR RADIAL VELOCITY TRENDS INDICATIVE OF THIRD COMPONENTS. BY COMBINING THE RESULTS OF THESE METHODS WE WILL BE ABLE TO INFER FOR THE FIRST TIME THE OCCURRENCE RATES OF THIRD BODIES IN A POPULATION OF SYSTEMS CURRENTLY UNDERGOING HIGH ECCENTRICITY MIGRATION.