title: Complex Chemistry Embracing Low-Mass Protostars Exposed

authors: Drozdovskaya M. N., Walsh C., Visser R., Harsono D., van Dishoeck E. F.

abstract: Complex organic molecules are trusty companions of young low-mass protostars. Traditionally such species have been observed in hot cores and corinos. More recently off-source locations with impingent outflows have also been shown to be bright in emission from complex organics [e.g., 1, 4, 5]. Furthermore, these compounds potentially contaminate protoplanetary and proto-cometary materials with organics. In this talk, physicochemical models are presented, including wavelength-dependent radiative transfer and an extensive gas-grain chemical network. In the first part, the effect of dynamic infall from the prestellar core towards the protoplanetary disk are discussed. The focus lies on methanol – a primary provider of radicals for further complex organic molecule synthesis. The budget and history of this precursor for two different protoplanetary disks, one growing primarily via viscous spreading and another dominated by infalling matter, are presented. The resul!
 ts show that the infall path influences the abundance of methanol entering each type of disc, ranging from complete loss of methanol to an enhancement by a factor of >1 relative to the prestellar phase [2]. In the second part, outflow cavity walls and the larger-scale envelope are considered in the framework of a static physical model. Species illuminating the cavity walls in a time-dependent fashion are identified. In addition, a complex organic ice-rich region encompassing the young low-mass protostar appears in the simulations. A partitioning of complex organics into early and late species follows naturally from this work [3].

[1] Arce H. G., Santiago-Garcia J., Jorgensen J. K., Tafalla M., Bachiller R., 2008, ApJ, 681, L21
[2] Drozdovskaya M. N., Walsh C., Visser R., Harsono D., van Dishoeck E. F., 2014, MNRAS, 445, 913
[3] Drozdovskaya M. N., Walsh C., Visser R., Harsono D., van Dishoeck E. F., 2015, in prep.
[4] Oberg K. I., Bottinelli S., Jorgensen J. K., van Dishoeck E. F., 2010, ApJ, 716, 825
[5] Oberg K. I., van der Marel N., Kristensen L. E., van Dishoeck E. F., 2011, ApJ, 740, 14