Year: 2025
Type: article
Abstract: Mass loss is a key physical process in the evolution of massive stars, the impact of which propagates into galactic evolution, population synthesis models, the interpretation of high-redshift galaxies, and explosive events such as supernovae. However, there are currently substantial uncertainties in the low-metallicity, low-luminosity thin wind regime where classical diagnostics (Hα and ultraviolet, UV, P Cygni profiles) yield wind momenta that are 1 to 2 orders of magnitude below prescriptions implemented by default in most evolutionary models. Here, we present spectra of the mass-loss diagnostic line Brα in 15 OB-type stars in the Small Magellanic Cloud obtained using the Near Infrared Spectrograph on the James Webb Space Telescope. The line profile morphology, recovered by virtue of the outstanding signal-to-noise ratio of the data and the avoidance of regions with nebular emission, is consistent with predictions based on previous mass-loss rate estimates from optical and UV spectroscopy. Moreover, an initial spectroscopic analysis of sources covering the thin wind regime confirms the low mass-loss rates, indicates a change of slope in the wind-momentum–luminosity relation in this regime with respect to high-luminosity objects, and strengthens the abovementioned discrepancies with commonly used wind-momentum prescriptions.
Institutions: Consejo Superior de Investigaciones Científicas, Centro de Astrobiología, Space Telescope Science Institute, Ludwig-Maximilians-Universität München, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Centre National de la Recherche Scientifique, Aix-Marseille Université, European Space Agency, University of Cincinnati, University of Pittsburgh, Universidad Autónoma de Madrid, KU Leuven
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Awards: G103270039, G1261033591, G1401168639, G1513912400, G2309174360, G2458569321, G256731684, G2660406951, G2818099032, G2858269097, G2914759765, G3298894584, G3326551379, G3480869486, G3518538256, G4140491619, G4212894969, G4679605298, G483893733, G5080475149, G5300652233, G5635532810, G6033112984, G6092473693, G613115604, G638709848, G6744423155, G7084143925, G7254781640, G7395345766, G7434936867, G7805626310, G8575141037, G8667377315, G871455044, G8920660035
OpenAlex ID: W4413812838