4 edition of On the origin and evolution of stellar chromospheres, coronae and winds found in the catalog.
On the origin and evolution of stellar chromospheres, coronae and winds
by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC, Springfield, Va
Written in English
|Series||[NASA contractor report] -- 112552., NASA contractor report -- NASA CR-112552.|
|Contributions||United States. National Aeronautics and Space Administration.|
|The Physical Object|
STARS AND STELLAR EVOLUTION Mixing 27 Recent Progress in Understanding the Origin of the Elements Mixing is a major factor in current uncertainties in models of stellar evolution and nucleosynthesis. Convec- tion is the primary mixing process in stellar astrophysics, and it is not well understood beyond the heuristic level of the one-parameter. The science frontier for stars and stellar evolution is as close as the Sun and as distant as exploding stars at redshift It includes understanding processes of exquisite complexity that connect the rotation of stars with their magnetic fields and areas of nearly total ignorance about phenomena that have been imagined but not yet observed, such as accretion-induced collapse.
Solar-like winds have their origins in stellar coronae (see Section ), so one might expect the winds to be correlated with coronal properties such as X-ray emission. Thus, in Figure Figure14 14 the mass loss rates measured from the astrospheric Ly α absorption (per unit surface area) are plotted versus X-ray surface fluxes (Wood et al Cited by: This concise and systematic account of the current state of this new branch of astrophysics presents the theoretical foundations of plasma astrophysics, magneto-hydrodynamics and coronal magnetic structures, taking into account the full range of available observation techniques from Price: $
Definition and empirical structure of the range of stellar chromospheres-coronae across the H-R diagram: cool stars Technical Report Linsky, J L Major advances in our understanding of non-radiative heating and other activity in stars cooler than T sub eff = 10,K has occured in the last few years. Other articles where Stellar evolution is discussed: star: Star formation and evolution: discovered stars that are well evolved or even approaching extinction, or both, as well as occasional stars that must be very young or still in the process of formation. Evolutionary effects on these stars are not negligible, even for a middle-aged star such as the Sun.
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The models will be constructed for stars of different spectral types and different evolutionary status; (5) To explain theoretically the "basal flux", the location of stellar temperature minima and the observed range of chromospheric activity for stars of the same spectral type; and (6) To construct self-consistent, time-dependent stellar wind models based on the momentum deposition by finite Author: Z.
Musielak. This grant was awarded by NASA to The University of Alabama in Huntsville (UAH) to construct state-of-the-art, theoretical, two-component, chromospheric models for single stars of different spectral types and different evolutionary status. On the Origin and Evolution of Stellar Chromospheres, Coronae and Winds Musielak, Z.
Abstract. This Author: Z. Musielak. On the Origin and Evolution of Stellar Chromospheres, Coronae and Winds and the decrease of this activity with stellar age.
In addition, for red giants and supergiants, we also proposed to construct self-consistent, purely theoretical wind models, and used these models to investigate the origin of "dividing lines" in the H-R diagram Author: Z. Musielak. Get this from a library.
On the origin and evolution of stellar chromospheres, coronae and winds: annual report, NASA grant NAG, Astrophysics Theory Program. [Z E Musielak; United States. National Aeronautics and Space Administration.]. This grant was awarded by NASA to The University of Alabama in Huntsville (UAH) to construct state-of-the-art, theoretical, two-component, chromospheric models for single stars of different spectral types and different evolutionary status.
In our proposal, we suggested to use these models to predict the level of the "basal flux", the observed range of variation of chromospheric activity for a. Chromospheres, coronae, and winds similar to those observed on the Sun have been detected in a variety of cool stars.
When the stellar radius becomes ~10 times of the Sun, the steady hot corona with temperature 10 6 K, suddenly disappears. Instead, many hot and warm (10 5 - 10 6 K) bubbles are formed in cool (T winds because of the thermal instability of the radiative cooling function; the red giant wind is not a steady stream but.
A model for a stellar wind driven by linear acoustic waves. On the Origin and Evolution of Stellar Chromospheres, Coronae and Winds Stellar winds are maintained by energy and momentum. Stellar coronae.
Coronal stars are ubiquitous among the stars in the cool half of the Hertzsprung–Russell diagram. These coronae can be detected using X-ray telescopes. Some stellar coronae, particularly in young stars, are much more luminous than the Sun's. For example, FK Comae Berenices is the prototype for the FK Com class of variable star.
These are giants of spectral types. filling factor Bofo and the stellar rotation period Prof. This relationship has been newly calculated by talking into account, very recent magnetic field measurements by Valenti et al. () and R,/iedi et al. (T), which are thought to be more accurate than earlier observational results.
Final Report NASA Grant NAG Astrophysics Theory Program On the Origin and Evolution of Stellar Chromospheres, Coronae and Winds Z. Musielak.
However, when the Goddard Colloquium on “Stellar Chromospheres”  ended this pre—space epoch of interesting advances in stellar atmospheric physics, the almost generally accepted, but a posteriori conservative opinion was that hot stars (especially 08 stars) could not have chromospheres—coronae because one could not identify any Author: R.
Stalio. Star - Star - Star formation and evolution: Throughout the Milky Way Galaxy (and even near the Sun itself), astronomers have discovered stars that are well evolved or even approaching extinction, or both, as well as occasional stars that must be very young or still in the process of formation.
Evolutionary effects on these stars are not negligible, even for a middle-aged star such as the Sun. Theoretical chromospheric models based on the short period acoustic wave theory are shown to have promise for explaining the heating of the lower chromospheres of quiet chromosphere stars, but are inadequate to explain the heating of transition regions and coronae of.
The gathering was to have both a historical character, appropriate for a bicenten nial, and a technical character, to note and chronicle the new phase of the history of the Observatory, which has prospered in parallel with the development of this fairly recent topic in astronomical research, the physics of stellar and solar coronae.
Planetary nebulae are the classic subject of astrophysics. The physical pro cesses occurring in this highly ionized gaseous medium, the formation of emis sion lines in clearly specified conditions, the continuous emission extending from the far ultraviolet up to infrared and radio frequencies, the generation of exotic forms of radiation predicted by atomic physics, along with methods for.
This book represents the proceedings of a NATO Advanced Study Institute which was held at Bonas from August 25 till Sep tember 5, and was devoted to the study of "Solar Phenomena in Stars and Stellar Systems". It is intended for a broad audi ence.
Students and post-doctoral scientists for. I discuss the scientific reasons why solar astronomers should be interested in other stars and why Solar Physics should be put in the broader context of Stellar Astrophysics.
Selected topics include stellar interiors and helioseismology, dynamo action and activity cycles, stellar surface activity, stellar chromospheres, coronae and winds, and Author: R. Pallavicini. The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.
Overview. The stellar atmosphere is divided into several regions of distinct character: The photosphere, which is the atmosphere's lowest and coolest layer, is normally its only visible part.
Light escaping from the surface of the star stems from this region. simulated stellar winds. In §5 we extensively discuss our results in light of observations of stellar winds (§) and chromospheres (§). In particular, we directly compare the simulated winds with the observations by Wood et al.(; ) in § In §, we discuss the results in terms of the faint young Sun paradox.
Start studying Chapter 20 Stellar Evolution. Learn vocabulary, terms, and more with flashcards, games, and other study tools.Stellar Model Chromospheres and Spectroscopic Diagnostics.
The related topics of stellar coronae and winds and their theoretical bases are beyond the scope of this review. Figure 8: A schematic illustration of the evolution of the stellar birthrate for different Hubble types.
The left panel shows the evolution of the relative SFR with.All stars are believed to possess expanding outer atmospheres known as stellar winds. Continual mass loss has a significant impact on stellar evolution, on the chemical evolution of galaxies (including the mass and energy budgets of the interstellar medium), and even on the long-term evolution .