MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 17 The infrared observations have also shown the presence of stellar populations that are not easily explained by our current understanding of star formation in a black hole environment. Such high angular resolution observations have led to several questions such as what is the origin of the nuclear massive young star clusters and why is there a dearth of old red giants around the central supermassive black hole? 2.6 The InterstellarMediumand Star Formation Star (or stellar system) formation and the interstellar medium are intricately related. The interplay between the two is central to fundamental issues of evolution of the Universe at one end and formation of planetary systems at the other, thus influencing virtually every theoretical and observational sub-field. While stellar astrophysics has entered a new era of exploration, a comprehensive picture of the star formation processes and the diverse conditions in the ISM is still elusive. The formation mechanisms of the two ends of the mass regime (the high-mass stars and the self- gravitating sub-stellar mass objects) remain poorly understood both theoretically and observationally. In a broader sense, the presence of dense molecular phase in the ISM is an important ingredient for star formation. On the other hand, the physical state of different phases of the ISM, including the dense molecular phase, is governed by the past and ongoing stellar activities. It is interesting to note that the metal enrichment of the ISMdepends on the integrated star formation history of the host galaxy. Thus, detailed studies of star formation and the physical conditions prevailing in different phases of the ISM are complementary to one another. There are a number of outstanding questions in this field that motivate researchers around the globe. A few are mentioned here. What is the detailed astro-chemistry, the origin of cosmic rays and their influence on the physical conditions in the ISM? Stars are born within molecular clouds, a process that begins almost as soon as the natal molecular gas has itself formed. This fundamental process of formation of the molecular clouds, which is the rate-determining step for star formation itself is yet to be observed. What are the mechanisms that lead to the formation of Giant Molecular Clouds (GMCs)? What is the contribution/interplay of turbulence, magnetic field and gravity in the formation of protostars? The effect of magnetic field on the star formation rate and the stellar initial mass function (IMF) is still an open question.Among the other pertinent questions in the field of star formation that are yet to be fully answered are, the role of jets/outflows in the star formation process, and the viable launching mechanisms of these. Once the cloud starts collapsing, due to the conservation of the angular momentum, they form accretion discs which have now been observationally confirmed to form as early as the protostar phase. Questions remain on exactly how the angular momentum transport occurs, which lets the infalling gas relinquish its angular momentum to accrete on to the protostar. What are the roles played by the outflows, magnetic fields and various turbulences in the accretion disc? What is the detailed structure of the innermost regions of the disc? Is the accretion episodic for all young stars (like FUors and EXors), or only for a few perturbed systems? The key to understanding this active phase of the protoplanetary disc is via understanding and modelling the complex light curves from YSOs. With the data from modern multi-epoch photometric and spectroscopic time domain astronomy surveys, it will be possible to understand the complex physics of accretion in young stellar objects. What are the processes involved in filtering the chemistry- drivingUV radiation incident on the disc that alter the composition of forming planetary systems? Understanding the various feedback manifestations and mechanisms of high-mass stars is an upcoming field. The strong UV radiation field of the high-mass stars affect the ISM both physically, chemically and mechanically. Easily MEGA SCIENCE VISION-2035