The National Academies Press

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Pages 325-341

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From page 325... ... Current observations with 8–10 m telescopes are sensitive to only the most massive planets, but extrapolations to ~30 m class facilities and reasonable improvements in instrumental capabilities can help find and characterize many more examples. In the longer term, the goal is to detect forming planets across a broad range of masses and orbital distances, transforming our understanding of planet formation and early planetary system evolution. Read the entire page →
From page 326... ... org/10.1051/0004-6361/201935253. Image: Adapted from Skemer et al., 2014, Proceedings of SPIE 9148, Adaptive Optics Systems IV, 91480L, https://doi.org/10.1117/12.2057277. Read the entire page →
From page 327... ... In common with other fields, computational progress in ISM, star formation, and planet formation problems requires ongoing improvements in the size and efficiency of large, multiscale numerical simulations that include MHD and self-gravity. The largest simulations -- for example, of the launching of galactic winds owing to star-formation feedback into the ISM (F-Q1) Read the entire page →
From page 328... ... in molecular clouds? F-Q2b: What is the origin and prevalence of high-density structures in molecular clouds, and what role do they play in star formation? Read the entire page →
From page 329... ... HPC feedback, CGM/ISM, cosmic rays (F-Q1) ; development simulations of cloud to core scales with chemistry, nonideal MHD and radiation (F-Q2, F-Q3) Read the entire page →
From page 330... ... Stars also span an immense range in mass and size. The least massive stars are barely distinguishable from giant planets and have lifetimes that exceed the age of the universe. Read the entire page →
From page 331... ... We start with the Sun. The goal of modern solar physics research is to understand the entire Sun, from the core to the heliopause, in order to provide a holistic description of variations in its magnetic fields and the associated eruptive phenomena that can affect life on Earth. Read the entire page →
From page 332... ... Binary interaction has been shown to be a common and critical ingredient in the evolution of massive stars. Surveys show that interacting binaries are ubiquitous among these stars, accounting for at least 70 percent of the population, and that mass exchange can substantially modify their evolutionary trajectories. Read the entire page →
From page 333... ... We have also learned that about 10 percent of massive stars possess strong surface magnetic fields (~0.3–20 kG) and high rotation rates (>200 km/s at the equator) Read the entire page →
From page 334... ... Over the next decade, HR diagrams of the Milky Way from Gaia and of the local universe with the James Webb Space Telescope (JWST) , combined with theoretical explorations, will revolutionize our understanding of stars and stellar populations. Read the entire page →
From page 335... ... . Microlensing mass measurements with the Nancy Grace Roman Space Telescope (formerly the Wide-Field Infrared Survey Telescope [WFIRST] Read the entire page →
From page 336... ... Most stars orbit other stars. Those in very widely separated systems are crucial probes of star formation processes and coeval laboratories for stellar structure and evolution studies, and constrain the properties of the Milky Way's dark matter. Read the entire page →
From page 337... ... Information on systems with more than two stars is also lacking, despite their potential importance in Type Ia production and star-planet dynamics. With current and upcoming survey capabilities, we are poised to map multiplicity in exciting new ways, using astrometry from Gaia, gravitational waves from LIGO and LISA, and synoptic photometry from the Zwicky Transient Facility (ZTF) Read the entire page →
From page 338... ... Helioseismic data also reveal extra mixing below the solar convection zone, a feature not present in standard 1D models. Asymmetric processes affect the later evolutionary stages as well. Read the entire page →
From page 339... ... The Sun and other stars affect their environments in numerous ways, from the interaction of stellar winds, flares, coronal mass ejections (CMEs) and other forms of mass loss with surrounding disks, planetary bodies, stellar companions, and the interstellar medium, to the creation of planetary nebulae and supernova remnants and the end stages of stars. Read the entire page →
From page 340... ... Stellar mass loss through steady, episodic, or transient processes also influences the star's environment. The radiation-driven winds of massive stars interact with the circumstellar environment, creating nebulae filled with gas and dust. Read the entire page →
From page 341... ... This capacity will be accomplished through advancements and investment in instrumentation and facilities, improvements and standardization of spectroscopic reduction and analysis techniques, archival storage and broad community access to data products, development of novel approaches to explore the highly multidimensional data sets that will emerge from these efforts, and support for laboratory astrophysics, including theory and experiment. Astronomy became astrophysics with the first spectrum. Read the entire page →

From page 325...

... Current observations with 8–10 m telescopes are sensitive to only the most massive planets, but extrapolations to ~30 m class facilities and reasonable improvements in instrumental capabilities can help find and characterize many more examples. In the longer term, the goal is to detect forming planets across a broad range of masses and orbital distances, transforming our understanding of planet formation and early planetary system evolution.