CPW Science Passage
... CPW Science Passage 9th Grade An astronomy class is given the following facts about stellar evolution. 1. A star’s evolution can be divided in two 3 stages: pre-main sequence (pre-MS), main sequence (MS), and post-main sequence (post-MS). 2. Gravity causes part of a cloud of gas and dust to collapse ...
... CPW Science Passage 9th Grade An astronomy class is given the following facts about stellar evolution. 1. A star’s evolution can be divided in two 3 stages: pre-main sequence (pre-MS), main sequence (MS), and post-main sequence (post-MS). 2. Gravity causes part of a cloud of gas and dust to collapse ...
NSDL_WS_1_Astonomy
... The most important factor in how a star evolves and eventually dies is its initial mass. ...
... The most important factor in how a star evolves and eventually dies is its initial mass. ...
Red supergiants and the past of Cygnus OB2
... Methods. Near-infrared star counts in the Cygnus region reveal moderate evidence for a peak in the areal density of bright, reddened stars approximately coincident with Cygnus OB2. A total of 11 sources are found within a circle of 1◦ radius centered on the association, of which 4 are non-supergiant ...
... Methods. Near-infrared star counts in the Cygnus region reveal moderate evidence for a peak in the areal density of bright, reddened stars approximately coincident with Cygnus OB2. A total of 11 sources are found within a circle of 1◦ radius centered on the association, of which 4 are non-supergiant ...
Evolution of stars
... b. stars expand when they become giants. c. stars support their weight by making energy. d. the helium flash occurs in degenerate matter. e. all stars on the main sequence have about the same radius. 64. Due to the dust in the interstellar medium, a star will appear to an observer on Earth to be a. ...
... b. stars expand when they become giants. c. stars support their weight by making energy. d. the helium flash occurs in degenerate matter. e. all stars on the main sequence have about the same radius. 64. Due to the dust in the interstellar medium, a star will appear to an observer on Earth to be a. ...
1. INTRODUCTION - Institut für Theoretische Astrophysik
... either. Interestingly, both approximations are expected to change the thermal structure of the atmospheres in opposite directions : ignoring the ionization energy of hydrogen in the energy equation produces an atmosphere that is deÐnitely too hot, while including this term but omitting the advective ...
... either. Interestingly, both approximations are expected to change the thermal structure of the atmospheres in opposite directions : ignoring the ionization energy of hydrogen in the energy equation produces an atmosphere that is deÐnitely too hot, while including this term but omitting the advective ...
Mn, Cu, and Zn abundances in barium stars and their correlations
... (Sneden et al. 1991). They are thought to be produced through a variety of nucleosynthetic processes, including explosive nucleosynthesis in SN II and SN Ia, the main component of the s-process, thought to occur in the He-burning shells of low to intermediate mass AGB stars, and the weak component o ...
... (Sneden et al. 1991). They are thought to be produced through a variety of nucleosynthetic processes, including explosive nucleosynthesis in SN II and SN Ia, the main component of the s-process, thought to occur in the He-burning shells of low to intermediate mass AGB stars, and the weak component o ...
StellarManual
... An incomplete sentence is presented that indicates the size and surface temperature a certain star has relative to the Sun. Students should determine how the stellar luminosity will compare with the Sun. Initially there is no equation displayed. Answer: Luminosity of a star is proportional to the sq ...
... An incomplete sentence is presented that indicates the size and surface temperature a certain star has relative to the Sun. Students should determine how the stellar luminosity will compare with the Sun. Initially there is no equation displayed. Answer: Luminosity of a star is proportional to the sq ...
Astronomy Astrophysics First detection of the field star overdensity in the Perseus... &
... located in the Perseus spiral arm, with five of them very close to the anticenter. Their model for the spiral arms locates the Perseus arm at 2 kpc at around = 180◦, with the five masers placed at slightly smaller galactocentric radius than the fit. Vallée (2014) published a master catalog of the ...
... located in the Perseus spiral arm, with five of them very close to the anticenter. Their model for the spiral arms locates the Perseus arm at 2 kpc at around = 180◦, with the five masers placed at slightly smaller galactocentric radius than the fit. Vallée (2014) published a master catalog of the ...
Dynamical Mass Measurements of Pre-Main
... radial velocities of the primary stars relative to their secondaries (e.g., Rucinski, 1999). These effects can be minimized by selecting templates that are well matched to the target stars in spectral type, by avoiding orbital phases subject to strong line blending, and by employing techniques desig ...
... radial velocities of the primary stars relative to their secondaries (e.g., Rucinski, 1999). These effects can be minimized by selecting templates that are well matched to the target stars in spectral type, by avoiding orbital phases subject to strong line blending, and by employing techniques desig ...
The cosmic origin of fluorine and sulphur
... Practically only the two lightest elements, hydrogen and helium, were formed during the Big Bang when our Universe was born. All other elements have been formed, and keep being formed, in different processes in different types of stars. is means that all atoms, except hydrogen and helium, that build ...
... Practically only the two lightest elements, hydrogen and helium, were formed during the Big Bang when our Universe was born. All other elements have been formed, and keep being formed, in different processes in different types of stars. is means that all atoms, except hydrogen and helium, that build ...
Astronomy Astrophysics Circumstellar emission in Be/X-ray binaries of the Magellanic
... Aims. We study the optical and near-infrared colour excesses produced by circumstellar emission in a sample of Be/X-ray binaries. Our main goals are exploring whether previously published relations, valid for isolated Be stars, are applicable to Be/X-ray binaries and computing the distance to these ...
... Aims. We study the optical and near-infrared colour excesses produced by circumstellar emission in a sample of Be/X-ray binaries. Our main goals are exploring whether previously published relations, valid for isolated Be stars, are applicable to Be/X-ray binaries and computing the distance to these ...
Abstracts - Physics of Evolved Stars 2015
... During the past decade, an increasing number of observations have shown that, at least at some points, the mass-loss rate of red supergiants (RSG) could be significantly higher than the standard one, usually used in stellar evolution code. In this talk, I will show how an increased mass-loss rate du ...
... During the past decade, an increasing number of observations have shown that, at least at some points, the mass-loss rate of red supergiants (RSG) could be significantly higher than the standard one, usually used in stellar evolution code. In this talk, I will show how an increased mass-loss rate du ...
Star
A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.