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We report on the properties of the low-mass stars that recently formed in thecentral ~ 2.7'x2.7' of 30 Dor including the R136 cluster. Using the photometriccatalogue of De Marchi et al. (2011c), based on observations with the HubbleSpace Telescope (HST), and the most recent extinction law for this field, weidentify 1035 bona-fide pre-main sequence (PMS) stars showing Halpha excessemission at the 4 sigma level with Halpha equivalent width of 20 AA or more. Wefind a wide spread in age spanning the range ~ 0.1-50 Myr. We also find thatthe older PMS objects are placed in front of the R136 cluster and are separatedfrom it by a conspicuous amount of absorbing material, indicating that starformation has proceeded from the periphery into the interior of the region. Wederive physical parameters for all PMS stars, including masses m, ages t, andmass accretion rates M_acc. To identify reliable correlations between theseparameters, which are intertwined, we use a multivariate linear regression fitof the type log M_acc = a log t + b log m + c. The values of a and b for 30 Dorare compatible with those found in NGC 346 and NGC 602. We extend the fit to auniform sample of 1307 PMS stars with 0.5 < m/Msun < 1.5 and t < 16 Myr in sixstar forming regions in the Large and Small Magellanic Clouds and Milky Waywith metallicities in the range 0.1-1.0 Zsun. We find a=-0.59+/-0.02 andb=0.78+/-0.08. The residuals are systematically different between the sixregions and reveal a strong correlation with metallicity Z, of the type c =(-3.69+/-0.02) - (0.30+/-0.04) log Z/Zsun. A possible interpretation of thistrend is that when the metallicity is higher so is the radiation pressure andthis limits the accretion process, both in its rate and duration.

Photometric determination of the mass accretion rates of pre-main sequence stars. V. Recent star formation in the 30 Dor nebula