Stars like our sun form out of the gravitational collapse of the highest density regions of the interstellar medium, the dense cores. Observing the evolutionary sequence from cores to protostars is of fundamental importance to understand the physics of star formation and to disentangle between the different collapse scenarios. In this sense, star formation research can be naively divided in two main branches: the and backward and approach which studies the protostar formation by observing the youngest and protostars and the and forward and approach which studies the starless cores closest to gravitational collapse.
The borderline between these two can be drawn by the observation of an infrared point sources embedded in th e core. Since this work has been usually done using images from the IRAS satellite, the advent of the more sensitive Spitzer space telescope was bound to have a large impact on the identification of embedded protostars.In fact, Spitzer recently identified very low-luminosity sources in some previously thought and starless and cores.
The discovery of these extremely faint sources opened a series of very important questions:
1. Is there any difference in the structure of the cores with Spitzer objects compared to the and real and starless cores? And what are the differences between cores with Spitzer sources and cores with IRAS sources?
2. What is the nature of the Spitzer sources? Are they low luminosity protostars just because of their mass or are they so young that they have not accumulated most of their mass?
3. Can we put together an evolutionary sequence of cores from the chemically young L1521E to the very evolved L1521F, which harbours a Spitzer source?
We propose to answer these questions by studying the physical and chemical conditions of these newly identified and starred and cores through high resolution observations of their gas and dust contents.
Call for proposal
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