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Showing 1-3 of about 3 results.
Zooming in on Individual Star Formation: Low- and High-Mass StarsRosen, Anna L.Offner, Stella S. R.Sadavoy, Sarah I.Bhandare, AsmitaVázquez-Semadeni, EnriqueGinsburg, AdamDOI: info:10.1007/s11214-020-00688-5v. 21662
Rosen, Anna L., Offner, Stella S. R., Sadavoy, Sarah I., Bhandare, Asmita, Vázquez-Semadeni, Enrique, and Ginsburg, Adam. 2020. "Zooming in on Individual Star Formation: Low- and High-Mass Stars." Space Science Reviews 216:62.
ID: 157686
Type: article
Authors: Rosen, Anna L.; Offner, Stella S. R.; Sadavoy, Sarah I.; Bhandare, Asmita; Vázquez-Semadeni, Enrique; Ginsburg, Adam
Abstract: Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds (∼10 s pc) down to the size scales of dense prestellar cores (∼0.1 pc) that are the birth sites of stars. Several physical processes like turbulence, magnetic fields and stellar feedback, such as radiation pressure and outflows, are more or less important for different stellar masses and size scales. During the last decade a variety of technological and computing advances have transformed our understanding of star formation through the use of multi-wavelength observations, large scale observational surveys, and multi-physics multi-dimensional numerical simulations. Additionally, the use of synthetic observations of simulations have provided a useful tool to interpret observational data and evaluate the importance of various physical processes on different scales in star formation. Here, we review these recent advancements in both high- (M ≳8 M) and low-mass star formation.
Formation and Evolution of Disks Around Young Stellar ObjectsZhao, BoTomida, KengoHennebelle, PatrickTobin, John J.Maury, AnaëlleHirota, TomoyaSánchez-Monge, ÁlvaroKuiper, RolfRosen, Anna L.Bhandare, AsmitaPadovani, MarcoLee, Yueh-NingDOI: info:10.1007/s11214-020-00664-zv. 21643
Zhao, Bo, Tomida, Kengo, Hennebelle, Patrick, Tobin, John J., Maury, Anaëlle, Hirota, Tomoya, Sánchez-Monge, Álvaro, Kuiper, Rolf, Rosen, Anna L., Bhandare, Asmita, Padovani, Marco, and Lee, Yueh-Ning. 2020. "Formation and Evolution of Disks Around Young Stellar Objects." Space Science Reviews 216:43.
ID: 157687
Type: article
Authors: Zhao, Bo; Tomida, Kengo; Hennebelle, Patrick; Tobin, John J.; Maury, Anaëlle; Hirota, Tomoya; Sánchez-Monge, Álvaro; Kuiper, Rolf; Rosen, Anna L.; Bhandare, Asmita; Padovani, Marco; Lee, Yueh-Ning
Abstract: Recent observations have suggested that circumstellar disks may commonly form around young stellar objects. Although the formation of circumstellar disks can be a natural result of the conservation of angular momentum in the parent cloud, theoretical studies instead show disk formation to be difficult from dense molecular cores magnetized to a realistic level, owing to efficient magnetic braking that transports a large fraction of the angular momentum away from the circumstellar region. We review recent progress in the formation and early evolution of disks around young stellar objects of both low-mass and high-mass, with an emphasis on mechanisms that may bridge the gap between observation and theory, including non-ideal MHD effects and asymmetric perturbations in the collapsing core (e.g., magnetic field misalignment and turbulence). We also address the associated processes of outflow launching and the formation of multiple systems, and discuss possible implications in properties of protoplanetary disks.
Massive-star Formation via the Collapse of Subvirial and Virialized Turbulent Massive CoresRosen, Anna L.Li, Pak ShingZhang, QizhouBurkhart, BlakesleyDOI: info:10.3847/1538-4357/ab54c6v. 887108
Rosen, Anna L., Li, Pak Shing, Zhang, Qizhou, and Burkhart, Blakesley. 2019. "Massive-star Formation via the Collapse of Subvirial and Virialized Turbulent Massive Cores." The Astrophysical Journal 887:108.
ID: 154533
Type: article
Authors: Rosen, Anna L.; Li, Pak Shing; Zhang, Qizhou; Burkhart, Blakesley
Abstract: Similar to their low-mass counterparts, massive stars likely form via the collapse of prestellar molecular cores. Recent observations suggest that most massive cores are subvirial (i.e., not supported by turbulence) and therefore are likely unstable to gravitational collapse. Here we perform radiation-hydrodynamic simulations to follow the collapse of turbulent massive prestellar cores with subvirial and virialized initial conditions to explore how their dynamic state affects the formation of massive stars and core fragmentation into companion stars. We find that subvirial cores undergo rapid monolithic collapse, resulting in higher accretion rates at early times as compared to the collapse of virialized cores that have the same physical properties. In contrast, we find that virialized cores undergo a slower, gradual collapse and significant turbulent fragmentation at early times, resulting in numerous companion stars. In the absence of strong magnetic fields and protostellar outflows, we find that the faster growth rate of massive stars that are born out of subvirial cores leads to an increase in the radiative heating of the core, thereby further suppressing fragmentation at early times when turbulent fragmentation occurs for virialized cores. Regardless of initial condition, we find that the massive accretion disks that form around massive stars dominant the accretion flow onto the star at late times and eventually become gravitationally unstable and fragment to form companion stars at late times.