The JCMT Gould Belt Survey: radiative heating by OB stars

TL;DR

This study quantifies how OB stars radiatively heat surrounding dust in local star-forming regions, revealing that massive stars significantly influence dust temperatures over parsec scales, affecting star formation environments.

Contribution

It provides the first detailed quantification of radiative heating effects by OB stars on dust temperatures in nearby star-forming regions using JCMT Gould Belt survey data.

Findings

O-type stars cause dust temperatures over 40 K up to 2.4 pc away.

Early B-type stars raise temperatures above 20 K within 0.4 pc.

24% of clumps are heated at least 3 K above the base temperature.

Abstract

Radiative feedback can influence subsequent star formation. We quantify the heating from OB stars in the local star-forming regions in the JCMT Gould Belt survey. Dust temperatures are calculated from 450/850 micron flux ratios from SCUBA-2 observations at the JCMT assuming a fixed dust opacity spectral index $\beta=1.8$. Mean dust temperatures are calculated for each submillimetre clump along with projected distances from the main OB star in the region. Temperature vs. distance is fit with a simple model of dust heating by the OB star radiation plus the interstellar radiation field and dust cooling through optically thin radiation. Classifying the heating sources by spectral type, O-type stars produce the greatest clump average temperature rises and largest heating extent, with temperatures over 40 K and significant heating out to at least 2.4 pc. Early-type B stars (B4 and above) produce temperatures of over 20 K and significant heating over 0.4 pc. Late-type B stars show a marginal heating effect within 0.2 pc. For a given projected distance, there is a significant scatter in clump temperatures that is due to local heating by other luminous stars in the region, projection effects, or shadowing effects. Even in these local, `low-mass' star-forming regions, radiative feedback is having an effect on parsec scales, with 24% of the clumps heated to at least 3 K above the 15 K base temperature expected from heating by only the interstellar radiation field, and a mean dust temperature for heated clumps of 24 K.