Hubble Space Telescope Imaging of the Schwartz

Schwartz 82 (IM Lupi; HBC 605; IRAS 15528-3747) is an M0 T Tauri star located within the Lupus star forming clouds at a distance of ∼190 pc (Wichmann et al. 1998). It is one of four young stellar objects in a small CO(1-0) core near the extreme T Tauri star RU Lupi (Tachihara et al. 1996). Unlike its more famous neighbor, Sz 82 displays only a modest amount of emission-line activity, with an Hα equivalent width which is known to vary from 7.5 21.5 aA (Batalha & Basri 1993). A detailed study of Hα emission in this star by Reipurth et al. (1996) concluded that the Hα feature shows an inverse P Cygni pro£le with evidence for infall. The relatively weak emission lines and lack of optical veiling caused Finkenzeller & Basri (1987) and Martin et al. (1994) to classify this object as a weak-line T Tauri star, although it is more properly catagorized as a borderline classical T Tauri star. The V-band linear polarization of Sz 82 is low, 0.5%± 0.1% at a position angle of 1 (Bastien 1985). The star is an irregular variable (Batalha et al. 1998), and has been observed to ¤are dramatically in the U band (Gahm et al. 1993). Hipparcos observations suggested a companion with a separation of only 0.4 arcsec (Wichmann et al. 1998); however, neither nearIR speckle observations (Ghez et al. 1997) nor the current HST observations con£rm the presence of a close companion. Ages for this system range from 10 yr to 10 yr (Hughes et al. 1994), depending on the pre-main sequence evolutionary track used. Sz 82 is not associated with any known optical or molecular out¤ow, although HH 55 is located nearby.