Efficient methanol desorption in shear instability
/ Authors
J. Harju, J. Pineda, A. Vasyunin, P. Caselli, S. Offner, A. Goodman, M. Juvela, Olli Sipilae, A. Faure, R. L. Gal
and 16 more authors
P. Hily-Blant, J. Alves, L. Bizzocchi, A. Burkert, H. Chen, R. Friesen, R. Guesten, P. Myers, A. Punanova, C. Rist, E. Rosolowsky, S. Schlemmer, Y. Shirley, S. Spezzano, C. Vastel, Laurent Wiesenfield
/ Abstract
We present ALMA maps of the starless molecular cloud core Ophiuchus/H-MM1 in the lines of deuterated ammonia (ortho-NH2D), methanol (CH3OH), and sulphur monoxide (SO). While the dense core is outlined by NH2D emission, the CH3OH and SO distributions form a halo surrounding the core. Because methanol is formed on grain surfaces, its emission highlights regions where desorption from grains is particularly efficient. Methanol and sulphur monoxide are most abundant in a narrow zone that follows one side of the core. The region of the brightest emission has a wavy structure that rolls up at one end. This is the signature of Kelvin-Helmholtz instability occurring in sheared flows. We suggest that in this zone, methanol and sulphur are released as a result of grain-grain collisions induced by shear vorticity.
Journal: arXiv: Astrophysics of Galaxies