Spatial statistics in star-forming regions: is star formation driven by column density alone?

ABSTRACT Star formation is known to occur more readily where raw materials are available. This often expressed by a ‘Kennicutt–Schmidt’ relation the surface density of young stellar objects (YSOs) proportional column some power, ?. The aim this work was determine if alone sufficient explain locations Class 0/I YSOs within Serpens South, Core, Ophiuchus, NGC 1333, and IC348, or there clumping avoidance that would point additional influences on star formation. Using O-ring test as summary statistic, 95 per cent confidence envelopes were produced for different values ? from probability models made using Herschel maps. tested against four distribution models: best estimate region, = 0 above minimum threshold, zero elsewhere, 1, power law represents five regions collective, 2.05 ± 0.20. Results showed model consistent with majority and, those regions, spatial at given being random. South 1333 rejected small scales ${\sim}0.15\, \mathrm{pc}$ which implies small-scale interactions may be necessary improve model. On 0.15 pc, positions in all can well described alone.