T Tauri, the prototype of a class of low-mass pre-main sequence stars,
was observed with the 3.6m Canada-France-Hawaii telescope (CFHT) and
the CP40 photon-counting camera in November 1989. The data have been a
nalysed using techniques of Speckle Interferometry to obtain diffracti
on-limited information on the spatial extent of T Tauri in narrow pass
bands centered on the H alpha line and the nearby red continuum. The o
bject appears unresolved in the continuum passband, while it is resolv
ed in H alpha. The H alpha emission is fitted with a model consisting
of two strongly flattened two-dimensional gaussians. In this model app
roximate to 80% of the flux lies in a component (A) which is only marg
inally resolved, and approximate to 20% lies in a component (B) with a
semi-major axis FWHM of approximate to 0 ''.09. After subtraction of
continuum, 2/3 of the H alpha emission is spatially unresolved and 1/3
is resolved. The position angle(1) of component B is 192 degrees +/-
5 degrees, which approximates the direction of the perpendicular to th
e jet known in the [OI] and [SII] lines; this jet extends 30 '' westwa
rds up to the Herbig-Haro object HH1555. The corresponding linear size
of the H alpha emitting region B is similar to 6 by 15 AU FWHM assumi
ng a distance of T Tauri of d = 140pc. We argue that this emission ari
ses either from the interaction between a weakly collimated wind with
a circumstellar flaring disc, or from the basis of the westward jet wh
ich is seen on a larger scale.