Abstract.
The relative role played by the magnetic field and the turbulence in
cloud formation and evolution and in different stages of star
formation is a matter of serious study. By using linear polarization
measurements in optical wavelengths of stars that are located behind
the clouds, one can map the plane-of-sky component of magnetic
field. Here we present the preliminary results of the linear
polarimetry of background stars projected on three clouds, namely,
IRAM 04191+1522 (R band), L1521F (V band) and L1014 (R band).
These clouds, previously classified as starless, are found to
harbour very low luminosity objects (VeLLOs, L ≤ 0.1 L⊙)
detected during observations with Spitzer Space telescope (SST). A
protostar located on the stellar/substellar boundary
(M=0.08M⊙) would have an accretion luminosity of
L∼
1.6L⊙, assuming a spherical mass accretion predicted by the
standard model onto a protostellar object of typical radius R∼ 3
R⊙. VeLLOs, with luminosities more than an order of
magnitude lower than this, are difficult to understand in the
context of standard model of star formation.
Key words:ISM: magnetic fields -- polarization -- star: formation