Annachiara Picco - Academia.edu (original) (raw)
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Papers by Annachiara Picco
arXiv (Cornell University), Sep 10, 2023
An in-depth analysis of the stellar matter resistance to energy transport, the opacity, in the co... more An in-depth analysis of the stellar matter resistance to energy transport, the opacity, in the context of massive stars with high Zero Age Main Sequence (ZAMS) mass is performed. The opacity of astrophysical plasmas stands up as key in Stellar Evolution Codes (SECs) input physics, as it is know to dramatically affect model predictions of structural as well as evolutionary properties of stellar objects; by virtue of this paramount role, stellar plasma’s opaqueness is examined both as a stand-alone micro- physical process and as the possible origin of consistent evolutionary effects. The implementation, in the PAdova TRieste Evolutionary Code (PARSEC), of a refined sub-routine for relativistic electron scattering, with arbitrary degree of degeneracy, is followed by a thorough discussion of its consequent evolutionary impacts, within a varied stellar models grid. Furthermore, the author argues about the importance of thermal conductivity in the most advanced evolutionary stages, thus p...
In this work we analysed some essential physics of a protoplanetary disk, then the most important... more In this work we analysed some essential physics of a protoplanetary disk, then the most important models of dust dynamics are browsed, to conclude with a study of coagulative processes starting from the now classic Smoluchowski equation (1916), while following some more recent theoretical patterns and keeping an eye on order of magnitude estimates where possible. i * * * Chapter 1 Protoplanetary Disks A protoplanetary disk is the result of the collapse of a molecular cloud of gas and dust due to gravity. Under the action of the competing forces associated with gravity, gas pressure, magnetic support and rotation, the contracting nebula begins to spin faster because of angular momentum conservation, as it starts to flatten, under the effect of stronger centrifugal forces, into a spinning disk with a bulge at the center. The instabilities in the collapsing and rotating cloud cause localized gravitational collapses, and the bulge becomes the central star.
arXiv (Cornell University), Sep 10, 2023
An in-depth analysis of the stellar matter resistance to energy transport, the opacity, in the co... more An in-depth analysis of the stellar matter resistance to energy transport, the opacity, in the context of massive stars with high Zero Age Main Sequence (ZAMS) mass is performed. The opacity of astrophysical plasmas stands up as key in Stellar Evolution Codes (SECs) input physics, as it is know to dramatically affect model predictions of structural as well as evolutionary properties of stellar objects; by virtue of this paramount role, stellar plasma’s opaqueness is examined both as a stand-alone micro- physical process and as the possible origin of consistent evolutionary effects. The implementation, in the PAdova TRieste Evolutionary Code (PARSEC), of a refined sub-routine for relativistic electron scattering, with arbitrary degree of degeneracy, is followed by a thorough discussion of its consequent evolutionary impacts, within a varied stellar models grid. Furthermore, the author argues about the importance of thermal conductivity in the most advanced evolutionary stages, thus p...
In this work we analysed some essential physics of a protoplanetary disk, then the most important... more In this work we analysed some essential physics of a protoplanetary disk, then the most important models of dust dynamics are browsed, to conclude with a study of coagulative processes starting from the now classic Smoluchowski equation (1916), while following some more recent theoretical patterns and keeping an eye on order of magnitude estimates where possible. i * * * Chapter 1 Protoplanetary Disks A protoplanetary disk is the result of the collapse of a molecular cloud of gas and dust due to gravity. Under the action of the competing forces associated with gravity, gas pressure, magnetic support and rotation, the contracting nebula begins to spin faster because of angular momentum conservation, as it starts to flatten, under the effect of stronger centrifugal forces, into a spinning disk with a bulge at the center. The instabilities in the collapsing and rotating cloud cause localized gravitational collapses, and the bulge becomes the central star.