Distribution of Serpens South protostars revealed with ALMA

ARCE, HÉCTOR G.; DUNHAM, MICHAEL M.; PLUNKETT, ADELE L.; BUSQUET, GEMMA; MANUEL FERNANDEZ LOPEZ; MARDONES, DIEGO

Congreso; American Astronomical Society, AAS Meeting #233; 2019

Clusters are common sites of star formation, and their members display varying degrees of mass segregation. The cause may be primordial or dynamical, or a combination both. If mass segregation were to be observed in a very young protostellar cluster, then the primordial case can be assumed more likely for that region. We investigated the masses and spatial distributions of pre-stellar and protostellar candidates in the young, low-mass star forming region Serpens South, where active star formation is known to occur along a predominant filamentary structure. In Plunkett et al. (2018) we presented ALMA observations of 1 mm (Band 6) continuum in a 3 x 2 arcmin region at the center of Serpens South. Our angular resolution of 1 arcsec is equivalent to 400 au, corresponding to scales of envelopes and/or disks of protostellar sources. We detected 52 sources with 1 mm continuum, and we measured disk/envelope masses of 0.002-0.9 solar masses. For the deeply embedded (youngest) sources with no IR counterparts, we find evidence of mass segregation and clustering according to: the minimum spanning tree method, distribution of projected separations between unique sources, and concentration of higher-mass sources near to the dense gas at the cluster center. We conclude that the mass segregation of the mm sources is likely primordial rather than dynamical given the young age of this cluster, compared with segregation time. In this poster we also present an overview of statistical methods currently being used in the literature in order to quantify clustering, which previously had been used for stellar clusters and now can be used along with recent high-resolution/sensitivity mm-wave observations for the earlier cases of protostellar clusters.