Estimate the Kelvin-Helmholtz timescale for a 5 solar mass star on
... figure 13.7, and accommodate a drop in radius by a factor of 100 as the temperature rises from about 107 K to about 108 K between hydrogen exhaustion and helium core ignition, using a blackbody approximation for constant core luminosity). If these values are substituted into the above calculation, t ...
... figure 13.7, and accommodate a drop in radius by a factor of 100 as the temperature rises from about 107 K to about 108 K between hydrogen exhaustion and helium core ignition, using a blackbody approximation for constant core luminosity). If these values are substituted into the above calculation, t ...
Star in a Box Worksheet - Beginning
... complete, you can click on “Data Table” (upper right) to see the final values for each stage in the lifecycle. 1. Describe how the Sun changes over its lifetime. 2. When will the Sun be at its brightest? 3. When will the Sun be at its hottest? 4. In which stage of its life does the Sun spend the lon ...
... complete, you can click on “Data Table” (upper right) to see the final values for each stage in the lifecycle. 1. Describe how the Sun changes over its lifetime. 2. When will the Sun be at its brightest? 3. When will the Sun be at its hottest? 4. In which stage of its life does the Sun spend the lon ...
The correct answers are written in bold, italic and underlined. The
... Isolated stars do not gain mass. Fusion reactions convert lighter elements into heavier elements, but each heavier nucleus has less mass than the sum of the lighter nuclei that combined to form it. The difference in mass has been converted into energy, which ultimately is radiated from the star, so ...
... Isolated stars do not gain mass. Fusion reactions convert lighter elements into heavier elements, but each heavier nucleus has less mass than the sum of the lighter nuclei that combined to form it. The difference in mass has been converted into energy, which ultimately is radiated from the star, so ...
H-R Diagram - Faculty Website Listing
... and fire up Stellarium from Astronomy Apps. 3. The Spectral Type and Absolute Magnitude of the star can be searched in Stellarium using the Hipparcos Catalog Number. Using the given Hipparcos catalog numbers in Table 1 below, search and select each star in the list below by opening the search window ...
... and fire up Stellarium from Astronomy Apps. 3. The Spectral Type and Absolute Magnitude of the star can be searched in Stellarium using the Hipparcos Catalog Number. Using the given Hipparcos catalog numbers in Table 1 below, search and select each star in the list below by opening the search window ...
ASTR 200 : Lecture 15 Ensemble Properties of Stars
... Gas Cloud → Main Sequence → ??? • So, a large cloud (1000s to ~million solar masses) gets cold enough that many cores collapse into stars, giving a cluster • Each star clears gas disk away, but the cluster as a whole also blows out all the remaining interstellar gas, shutting down star formation • ...
... Gas Cloud → Main Sequence → ??? • So, a large cloud (1000s to ~million solar masses) gets cold enough that many cores collapse into stars, giving a cluster • Each star clears gas disk away, but the cluster as a whole also blows out all the remaining interstellar gas, shutting down star formation • ...
The Electromagnetic Spectrum
... you. • The train has a lower pitch when moving away from you. • This Doppler Effect is caused by compression or stretching of sound waves. • The same phenomenon occurs with light, only the ...
... you. • The train has a lower pitch when moving away from you. • This Doppler Effect is caused by compression or stretching of sound waves. • The same phenomenon occurs with light, only the ...
Background Information - Eu-Hou
... In order to plot a HR diagram, the temperature and luminosity of the stars need to be known. The simplest indication of a star’s temperature is its colour. A star’s colour is simply a measure of the amount of light from the star in one filter compared to another. The most common colour system is B-V ...
... In order to plot a HR diagram, the temperature and luminosity of the stars need to be known. The simplest indication of a star’s temperature is its colour. A star’s colour is simply a measure of the amount of light from the star in one filter compared to another. The most common colour system is B-V ...
The Birth of Stars
... of the Galaxy Clouds within the interstellar medium are called nebulae Dark nebulae are so dense that they are opaque – They appear as dark blots against a background of distant stars ...
... of the Galaxy Clouds within the interstellar medium are called nebulae Dark nebulae are so dense that they are opaque – They appear as dark blots against a background of distant stars ...
The Birth of Stars Guiding Questions • Because stars shine by
... 1. Why do astronomers think that stars evolve (bad use of term – this is about the birth, life and death of stars and that is NOT evolution)? 2. What kind of matter exists in the spaces between the stars? 3. In what kind of nebulae do new stars form? 4. What steps are involved in forming a star like ...
... 1. Why do astronomers think that stars evolve (bad use of term – this is about the birth, life and death of stars and that is NOT evolution)? 2. What kind of matter exists in the spaces between the stars? 3. In what kind of nebulae do new stars form? 4. What steps are involved in forming a star like ...
Type II supernova
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, and no more than 40–50 times, the mass of the Sun (M☉) for this type of explosion. It is distinguished from other types of supernovae by the presence of hydrogen in its spectrum. Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies.Stars generate energy by the nuclear fusion of elements. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing increasingly shorter stellar life spans. The degeneracy pressure of electrons and the energy generated by these fusion reactions are sufficient to counter the force of gravity and prevent the star from collapsing, maintaining stellar equilibrium. The star fuses increasingly higher mass elements, starting with hydrogen and then helium, progressing up through the periodic table until a core of iron and nickel is produced. Fusion of iron or nickel produces no net energy output, so no further fusion can take place, leaving the nickel-iron core inert. Due to the lack of energy output allowing outward pressure, equilibrium is broken.When the mass of the inert core exceeds the Chandrasekhar limit of about 1.4 M☉, electron degeneracy alone is no longer sufficient to counter gravity and maintain stellar equilibrium. A cataclysmic implosion takes place within seconds, in which the outer core reaches an inward velocity of up to 23% of the speed of light and the inner core reaches temperatures of up to 100 billion kelvin. Neutrons and neutrinos are formed via reversed beta-decay, releasing about 1046 joules (100 foes) in a ten-second burst. The collapse is halted by neutron degeneracy, causing the implosion to rebound and bounce outward. The energy of this expanding shock wave is sufficient to accelerate the surrounding stellar material to escape velocity, forming a supernova explosion, while the shock wave and extremely high temperature and pressure briefly allow for theproduction of elements heavier than iron. Depending on initial size of the star, the remnants of the core form a neutron star or a black hole. Because of the underlying mechanism, the resulting nova is also described as a core-collapse supernova.There exist several categories of Type II supernova explosions, which are categorized based on the resulting light curve—a graph of luminosity versus time—following the explosion. Type II-L supernovae show a steady (linear) decline of the light curve following the explosion, whereas Type II-P display a period of slower decline (a plateau) in their light curve followed by a normal decay. Type Ib and Ic supernovae are a type of core-collapse supernova for a massive star that has shed its outer envelope of hydrogen and (for Type Ic) helium. As a result, they appear to be lacking in these elements.