Is T Tauri North a 'Classical' T Tauri star?

Abstract

We present high-resolution $H$- and $K$-band spectroscopic observations of the archetypal T Tauri star T Tau North. Synthetic spectral modeling is used to derive the $K$-band temperature, surface gravity, magnetic field strength, and rotational velocity for this star. The $K$-band spectroscopic temperature measured is ${\mathrm{T}}_{\mathrm{K}\text{-band}}=3976\pm 90K$, which is $\sim 1000\mathrm{K}$ cooler than the temperature measured from optical observations. Our $K$-band temperature measurement for T Tau N is confirmed using equivalent width line ratio vs. temperature relations in the $H$-band, from which a ${\mathrm{T}}_{\mathrm{H}\text{-band}}=4085\pm 155K$ is derived. This optical vs. IR temperature difference is interpreted as cool or hot spots, or both, covering a significant part of the surface of T Tau N. The gravity derived for T Tau N $\log g=3.45\pm 0.14$ is lower than the gravity of nearly every other star in a sample of 24 classical T Tauri stars in Taurus. Combining these temperature and gravity results with magnetic stellar evolutionary models, we find the age of T Tau N to be less than 1 Myr old. These results suggest that T Tau N is in an earlier evolutionary stage than most classical T Tauri stars in Taurus, arguing that it is a protostar ejected from the embedded southern binary system shortly after its formation.

18 pages, 9 figures, 3 tables

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Cited by in corpus (1)

• A triple star in disarray -- Multi-epoch observations of T Tauri with VLT-SPHERE and LBT-LUCI