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arXiv · 2303.11347

Star-Crossed Lovers DI Tau A and B: Orbit Characterization and Physical Properties Determination

Shih-Yun Tang·Asa G. Stahl·L. Prato·G. H. Schaefer·Christopher M. Johns-Krull·Brian A. Skiff·Charles A. Beichman·Taichi Uyama
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Abstract

The stellar companion to the weak-line T Tauri star DI Tau A was first discovered by the lunar occultation technique in 1989 and was subsequently confirmed by a speckle imaging observation in 1991. It has not been detected since, despite being targeted by five different studies that used a variety of methods and spanned more than 20 years. Here, we report the serendipitous rediscovery of DI Tau B during our Young Exoplanets Spectroscopic Survey (YESS). Using radial velocity data from YESS spanning 17 years, new adaptive optics observations from Keck II, and a variety of other data from the literature, we derive a preliminary orbital solution for the system that effectively explains the detection and (almost all of the) non-detection history of DI Tau B. We estimate the dynamical masses of both components, finding that the large mass difference (q $\sim$0.17) and long orbital period ($\gtrsim$35 years) make DI Tau system a noteworthy and valuable addition to studies of stellar evolution and pre-main-sequence models. With a long orbital period and a small flux ratio (f2/f1) between DI Tau A and B, additional measurements are needed for a better comparison between these observational results and pre-main-sequence models. Finally, we report an average surface magnetic field strength ($\bar B$) for DI Tau A, of $\sim$0.55 kG, which is unusually low in the context of young active stars.

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Shih-Yun Tang, Asa G. Stahl, L. Prato, G. H. Schaefer, Christopher M. Johns-Krull, Brian A. Skiff, Charles A. Beichman, Taichi Uyama. 2023-03-20. Star-Crossed Lovers DI Tau A and B: Orbit Characterization and Physical Properties Determination. https://doi.org/10.3847/1538-4357%2Facc58b

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