Plateau de Bure interferometer observations of the disk and outflow of HH 30

¹ IRAM, 300 rue de la Piscine, 38400 Saint Martin d'Hères, France e-mail: [pety;gueth]@iram.fr
² LERMA, UMR 8112, CNRS, Observatoire de Paris, 61 Av. de l'Observatoire, 75014 Paris, France
³ L3AB, UMR 5804, Observatoire de Bordeaux, 2 rue de l'Observatoire, 33270 Floirac, France e-mail: [Stephane.Guilloteau;Anne.Dutrey]@obs.u-bordeaux1.fr

Received: 13 June 2006
Accepted: 26 July 2006

Abstract

Context.HH 30 is a well-known Pre-Main-Sequence star in Taurus. HST observations have revealed a flared, edge-on disk driving a highly-collimated optical jet, making this object a case study for the disk-jet-outflow paradigm.

Aims.We searched for a molecular outflow, and attempted to better constrain the star and disk parameters.

Methods.We obtained high angular resolution () observations of the dust continuum at 2.7 and 1.3 mm, and of the , and ,  emissions around HH 30. A standard disk model is used to fit the uv-plane visibilities and derive the disk properties, and the stellar mass. An ad hoc outflow model is used to reproduce the main properties of the emission.

Results.The rotation vector of the disk points toward the North-Eastern jet. The disk rotation is Keplerian: using a distance of 140 pc, we deduce a mass of 0.45 M_sun for the central star. The disk outer radius is 420 AU. A highly asymmetric outflow originates from the inner parts of the disk. Only its North-Eastern lobe was detected: it presents to first order a conical morphology with a  half opening angle and a constant (12 km s^-1) radial velocity field. Outflow rotation was searched for but not found. The upper limit of the outflow rotation velocity is 1 km s^-1 at 200 AU of the jet axis.

Conclusions.HH 30 is a low mass TTauri of spectral type around M1 and age 1 to 4 Myr, surrounded by a medium size Keplerian disk, of mass around 4  10^-3 M_sun. It beautifully illustrates the jet-disk-outflow interaction, being so far the only star to display a jet and outflow connected to a well defined Keplerian disk, but reveals a surprisingly asymmetric (one-sided) outflow despite a relatively symmetric jet. Furthermore, these observations do not enable to assign the origin of the molecular outflow to entrainment by the optical jet or to a disk wind. In the latter hypothesis, the lack of rotation would imply an origin in the inner 15 AU of the disk.