HD 34700 is a T Tauri multiple system

Abstract

We have imaged the young double-lined spectroscopic binary HD 34700 in the near-infrared and find evidence for two faint, visual, stellar components at 5″.2 and 9″2 distance. High-resolution echelle spectroscopy of both stars shows strong LiI 6708 Å absorption and Hα emission. The spectral types of the companions are estimated from the spectra and photometry as M1-M2 and M2-M3. Their radial velocities are similar to the center-of-mass velocity of the central SB2; hence all four stars are most probably physically bound and constitute a young quadruple stellar system with an inner short-period binary. We provide a list of pre-main sequence spectroscopic binaries with additional components of which HD 34700 is yet another example. The available statistics strengthen the suspicion that dynamical effects in multiple systems play a key role in the formation of very close binaries early in their evolution. © ESO 2005.