R CrA very low-mass objects JHK magnitudes

Fifteen Class I and 207 Class II candidates with NIR excess were selected from a [J-H]/[H-K] color-color diagram. Six low-mass stars, five brown dwarfs, and 196 planetary-mass object candidates were identified from the J-band luminosity of Class II candidates with the age assumption of 1 Myr using the evolutionary models. The derived initial mass function (IMF) does not appear to decrease in the brown dwarf and planetary-mass regime, even when taking into account the background star and galactic contamination.

From comparison between the spatial distributions of Class I and II candidates and dust column densities derived from the Herschel observation, we found that all the low-mass star and brown dwarf candidates are located in the region where the dust column densities are higher than 2.5x10^21^cm^-2^, while planetary-mass object candidates are independent of their local dust densities. Our results suggest that the formations of low-mass stars and very low-mass objects may be dependent on the local cloud properties.