The TWA 3 Young Triple System: Orbits, Disks, Evolution

We have characterized the spectroscopic orbitof the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbitas well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located at 34 pc in the $\sim$10 Myr old TW Hya association. The wide component separation is 1."55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbitalsolution using high-resolution infrared spectroscopy which angularly resolved the A and B components. We then refined the preliminary orbitby combining the infrared data with a re-analysis of our high-resolution optical spectroscopy. The orbital periodfrom the combined spectroscopic solution is $\sim$35 days, the eccentricity is $\sim$0.63, and the mass ratio is $\sim$0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbitalsolution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planeswith respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least $\sim$30 degrees. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbitsand disk.