Project G
Following the Trail of Streamers feeding Baby Stars
Teresa Valdivia-Mena (ESO), Anna Miotello (ESO)
During the protostellar stage, baby stars accumulate mass by accreting from their surrounding disks. At the same time, planets may be already forming around the protostar, consuming material from the disk. We have long thought that stars and planets get their mass exclusively from their natal cores, but recent observations of asymmetric channels of gas called “streamers” have challenged the classical paradigm. Streamers can connect the protostellar disks with larger mass reservoirs outside the original cores, and thus replenish the material consumed by the protostar. This infall of material can potentially change the chemical properties of the disk where the streamer lands right at the time when planets are forming and possibly influence their final outcome.
The aim of this project is to disentangle the different kinematic structures around a baby star, to understand the connection between a protostellar disk and its environment. After selecting a source from a sample of new ALMA observations, the student will determine the kinematic properties of the gas: they will disentangle the different components of the protostar-disk system (disk, outflows, streamers, and envelope) using a combination of different molecular tracers (H2CO, C18O, SO, etc). The student will learn how to analyze the different physical structures around embedded protostars using data-cubes of molecular emission. They will use popular tools for ALMA data visualization and analysis (such as CASA), combined with python codes to understand the kinematic nature of the observed molecular emission. If time allows, the student will use different models available from literature to get the parameters of streamers (such as TIPSY) and disks (e.g. eddy). This way, the student can obtain the mass infall rate from streamer to disk, which can be further compared with the accretion rate toward the protostar known from the literature to quantify the effect of this additional infall mechanism in protostellar development.