Chemistry is an extremely powerful tool to estimate the duration of the prestellar phase; it can provide key tools to distinguish between a slow or a fast path towards the formation of stars. The most promising tracers of the quiescent phase are the light, depletion-resistant H_{2}{D}^{+} and D_{2}{H}^{+}. Our observational effort has led to the first detections of both ortho- and para-H_{2}{D}^{+} in massive clumps using APEX, ALMA and SOFIA. We confirm that the anticorrelation among the abundance of o-H_{2}{D}^{+} and N_{2}{D}^{+}, a species that can be relatively easily observed, is real and that their relative abundance strongly decreases with evolution in the very first stages of the star formation process. The behaviour of these species can be explained with simple considerations on the chemical formation paths, depletion of heavy elements, and evaporation from the dust grain mantles, and can be used as a powerful evolutionary indicator. Our unique 3D MHD simulations, coupled with chemistry, take us one step further than a simple relative timeline, allowing to follow abundance variations with time. Combining these pieces of the puzzle with the first measurement of the ortho-to-para ratio of H_{2}{D}^{+} in a massive clump, we will have the opportunity to investigate the duration of the quiescent phase in different mass regimes....
Giannetti, A., Bovino, S., Caselli, P., Leurini, S., Schleicher, D.R.G., Körtgen, B., et al. (2019). A timeline for massive star-forming regions via deuterium chemistry.
A timeline for massive star-forming regions via deuterium chemistry
Sabatini, G.
2019
Abstract
Chemistry is an extremely powerful tool to estimate the duration of the prestellar phase; it can provide key tools to distinguish between a slow or a fast path towards the formation of stars. The most promising tracers of the quiescent phase are the light, depletion-resistant H_{2}{D}^{+} and D_{2}{H}^{+}. Our observational effort has led to the first detections of both ortho- and para-H_{2}{D}^{+} in massive clumps using APEX, ALMA and SOFIA. We confirm that the anticorrelation among the abundance of o-H_{2}{D}^{+} and N_{2}{D}^{+}, a species that can be relatively easily observed, is real and that their relative abundance strongly decreases with evolution in the very first stages of the star formation process. The behaviour of these species can be explained with simple considerations on the chemical formation paths, depletion of heavy elements, and evaporation from the dust grain mantles, and can be used as a powerful evolutionary indicator. Our unique 3D MHD simulations, coupled with chemistry, take us one step further than a simple relative timeline, allowing to follow abundance variations with time. Combining these pieces of the puzzle with the first measurement of the ortho-to-para ratio of H_{2}{D}^{+} in a massive clump, we will have the opportunity to investigate the duration of the quiescent phase in different mass regimes....I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
