Multiple components in the molecular outflow of the red supergiant NML Cyg

ABSTRACT Despite their large impact on stellar and galactic evolution, the properties of outflows from red supergiants are not well characterized. We used Onsala 20m telescope to perform a spectral survey at 3 4 mm (68–116 GHz) supergiant NML Cyg, alongside yellow hypergiant IRC + 10420. Our observations Cyg were combined with complementary archival data enable search for signatures morphological complexity in circumstellar environment, using emission lines 15 molecular species. The recovered parameters imply presence three distinct, coherent, persistent components, comprised blue-shifted red-shifted addition an underlying outflow centred systemic velocity. Furthermore, reproduce 12CO 3D radiative transfer models required spherical superposed conical outflows, one towards away observer, plane sky. These components higher density than by up order magnitude. hence propose that Cyg’s environment consists small number high-density large-scale coherent embedded wind. This would make mass-loss history similar VY CMa, distinct ? Cep, where contains many randomly distributed smaller clumps. A possible correlation between properties, structures, content is critical understanding evolution massive stars environmental impact.