ALMA Observations Reveal Wind Structure and Mass Loss in Arches Cluster Massive Stars
Astronomers used the ALMA telescope to observe 23 massive stars in the Arches cluster, measuring their stellar winds and detecting clumped structures within those winds. The observations combined millimeter-wavelength data with archival radio observations to characterize how material flows from these extreme stars. These findings improve understanding of stellar feedback in one of the Milky Way's most massive young clusters.
Researchers presented the first ALMA Band 3 and Band 6 continuum observations of the Arches cluster, detecting millimeter emission from 23 massive stars including Wolf-Rayet stars and O-type supergiants. By combining ALMA measurements with archival Very Large Array radio data spanning 5–22.5 GHz, the team derived broadband spectral indices and investigated radial wind structure through frequency-dependent clumping diagnostics. Wolf-Rayet stars showed spectral indices consistent with thermal free-free emission from dense winds, while several O-type stars exhibited non-thermal synchrotron emission likely from colliding-wind binaries. The derived mass-loss rates ranged from approximately −4.1 to −5.4 solar masses per year, consistent with theoretical expectations for luminous massive stars in the Galactic Centre environment. The analysis revealed significant structured wind clumping at millimeter wavelengths that decreases with radius, supporting models of strong inner-wind inhomogeneities.
What different sources said
- arXiv astro-phCenter
ALMA measurements of mass loss and wind clumping in the massive stars of the Arches cluster
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