Research Interests

My research interests lie in the chemical and dynamical processes in protoplanetary disks, specifically the so-called \textit{transition} disks. The rapid advance in technology in the past few decades has allowed us to study these objects in great detail in several wavelength regimes. The full evolutionary picture between early prestellar cores to late planetary systems is not complete. In this context, understanding the chemical and dynamical processes that occur in protoplanetary disks provides a bridge between the two of them. Near-infrared and (sub)millimeter facilities have supplied us with several different molecular signatures that are key to distinguish the main Nitrogen-, Oxygen- and Carbon-bearing species that lead to the diverse molecular complexity found in planetary systems such as our own. The fundamental questions that motivate me are: How can we link the molecular diversity found in comets and in our solar system, in particular pre-organic components, to the early stages of planet formation? and what are the chemical and physical processes involved in the formation of the main tracers of Nitrogen-, Oxygen- and Carbon-bearing species in the different stages of planet formation?

In my first PhD project I analysed the first NH$_3$ gas-phase detection in the planet forming disk TW Hya \citep{Salinas2016}. Using {\bf LIME}, a 3D radiative transfer code, and existing water models from the literature, we proposed that if the bulk of the gaseous material is released from NH$_3$ and water intermixed ices then the emission is likely arising from the mid-plane following the mm-size grains. Since these observations came from the HIFI instrument on board the single-dish {\bf Herschel Telescope} we had no spatial information. To confirm or rule out this hypothesis we got an {\bf ALMA cycle 4 proposal accepted} ({\bf PI}, priority rank A) to observe the deuterated form of ammonia NH$_2$D in Band 8 and constrain its spatial location. Besides being the first gas-phase ammonia detection in protoplanetary disks, this result sheds some light into the unprobed nitrogen ice reservoir within them.

I am currently working on a set of three molecules detected with ALMA in Band 6 as part of a Cycle 2 proposal ({\bf Co-I}, priority rank A) N$_2$D$^+$, DCN and DCO$^+$. This molecules provide a good (but not full) picture of the different pathways on which deuterium is introduced to the chemistry. Our early fitting results confirm N$_2$D$^+$ to be tracing the CO snowline as previously reported and DCN tracing the high temperature deuteration channel. Our DCO$^+$ emission is specially intriguing. It seems to be following two regimes as described by \citet{Favre2015}. However, our early simple modelling suggests that DCO$^+$ is coming from the midplane also following the mm-size grains up to 290 au, the same way as hypothesised with NH$_3$. Its release mechanism is something to be discussed further. It might be linked to the hidden ice reservoir of deuterium-bearing species or CO. This paper should be submitted next month.

My past work has entailed both: a solid understanding of the underlying physical and chemical processes and proficiency at handling single-dish and interferometric data. For this purpose I have attended two schools focused on diverse processes and analysis techniques of {\bf Protoplanetary disks}. I have also attended the {\bf ERIS Interferometry school} in Garching which gave me the tools to recognise and diagnose potential problems when calibrating and imaging interferometric data. I have extensive experience with the the {\bf Common Astronomy Software Applications (CASA)} package and its applications. I have secured two Leids Kerkhoven-Bosscha Fonds (LKBF) grants to attend schools and conferences to show my work and establish professional collaborations within the community. I have also co-supervised two master projects, involving continuum modelling of ALMA millimeter emission of TW Hya, and collaborated together with Paola Pinilla and Mihkel Kama at my home institute to produce an MCMC fitting code. Within my research group I have given updates of my work through the astrochemical seminars and I attend regularly to the bi-weekly meetings of Star Formation and Protoplanetary Disks.

New interferometric facilities have revealed the radio universe in an unprecedented high spatial resolution. In particular, observations of the mm-size grains in protoplanetary disks around young stars have shown multiple sub-structures that were up to this point hidden. Such are the cases of the well known disks TW Hya, HL Tau and several others\citep{Andrews2016,ALMAPartnership2015,Zhang2016}. Similar structures are also detected in scattered light. The relationship between the milimiter emission, scattered light and gas structure (probed by CO isotopes) is not trival and so far most of the modelling efforts have been focused on reproducing these features separately.

In the future, coupled models of dust grain and gas evolution will help to understand the various morphologies across different tracers of protoplanetary disks. Simple molecules have already been seen in ring-like structures spawning at the same length scales, such as DCO$^+$ \citep[][and Salinas et al. 2016 in prep]{Oberg2015,Teague2015,Qi2015}. ALMA will allow observations of molecules tracing different physical conditions at high spatial resolution and sensitivity revealing detailed substructure and their link to the underlying physical structure of the disk.

I would also like to continue exploring the different regimes from where deuterated species arise to get a full picture of the mechanisms that get deuterium into the chemistry. Moreover, an important question on this matter is the initial condition of the deuterated species for further process in the protoplanetary disks. How much deuteration from the ISM survives the shocks and processes from early stages? How does deuteration changes across the acrettion shock?. Analysis of archival data or new ALMA proposals on early and late stages of star formation of key deuterated species such as DCO$^+$ or HDCO would help reconstruct the history of deuterium throughout the evolution of young stellar objects.