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   61021
   Several observations with ASCA and ROSAT have shown that protostars are
   emitting X-rays, sometimes at very high levels (Lx ~ 10^32 - 36 erg s-
   1), either steadily or during flares. However, the detected protostars
   are relatively evolved (Class I), with ages ~ 10^5 yrs. We want to
   investigate whether younger protostars (Class 0), with ages ~ 10^4 yrs,
   are also X-ray emitters. The detection of X-rays from low-mass
   protostars has major implications on early stages of evolution of stars
   and the solar nebula. The main difficulty arises from the high
   extinction (Av > 70 mag) of these objects, but ASCA is well suited to
   overcome this difficulty with the extended energy range. We propose
   deep exposures (50 ks) of two star-forming regions with Class 0
   sources, never observed so far in X-rays.
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