Stellar Evolution
... Sequence. As you look at more massive stars, convection is found only in layers near the surface. By the time you get to stars that have masses similar to that of the Sun, the mass fraction that is involved in convection is a very small part of the star at the surface (as is shown in the graph). As ...
... Sequence. As you look at more massive stars, convection is found only in layers near the surface. By the time you get to stars that have masses similar to that of the Sun, the mass fraction that is involved in convection is a very small part of the star at the surface (as is shown in the graph). As ...
Multiple sources or late injection of short-lived r
... early solar system (ESS) conclusively showed that these nuclides cannot simply be derived from galactic chemical evolution (GCE) if synthesized in a unique stellar environment. It was thus suggested that two different types of stars were responsible for the production of light and heavy r-nuclides. H ...
... early solar system (ESS) conclusively showed that these nuclides cannot simply be derived from galactic chemical evolution (GCE) if synthesized in a unique stellar environment. It was thus suggested that two different types of stars were responsible for the production of light and heavy r-nuclides. H ...
Interstellar Medium (ISM) Interstellar Extinction Star Formation
... where gravitational attraction causes a clump of material to condense into a protostar • As a protostar grows by the gravitational accretion of gases, KelvinHelmholtz contraction causes it to heat and begin glowing ...
... where gravitational attraction causes a clump of material to condense into a protostar • As a protostar grows by the gravitational accretion of gases, KelvinHelmholtz contraction causes it to heat and begin glowing ...
Introduction to Astrophysics, Lecture 13
... makes up only about one tenth of the material in the galaxy. While there is no doubt more material in the form of cold gas waiting to be made into stars, it is not believed that that will explain the difference. Instead, it is believed that most of the material in the galaxy is a new form of matter, ...
... makes up only about one tenth of the material in the galaxy. While there is no doubt more material in the form of cold gas waiting to be made into stars, it is not believed that that will explain the difference. Instead, it is believed that most of the material in the galaxy is a new form of matter, ...
Atypical thermonuclear supernovae from tidally crushed white dwarfs
... Several snapshots taken from our numerical simulations of a 0.2 M white dwarf approaching a 103 M black hole on a parabolic orbit with pericenter distance well within the tidal radius (rmin = rT /12) are shown in Figure 1. While falling inwards towards the hole, the star develops a quadrupole dist ...
... Several snapshots taken from our numerical simulations of a 0.2 M white dwarf approaching a 103 M black hole on a parabolic orbit with pericenter distance well within the tidal radius (rmin = rT /12) are shown in Figure 1. While falling inwards towards the hole, the star develops a quadrupole dist ...
Studying the Metallicities of Dwarf Galaxies Myles McKay (SCSU)
... • Most numerous extragalactic population in the local universe • Maybe the building blocks of more massive galaxies • Dwarf galaxies may be analogs to gas-rich galaxies at high redshift. • Insufficient star formation(some) GALEX ...
... • Most numerous extragalactic population in the local universe • Maybe the building blocks of more massive galaxies • Dwarf galaxies may be analogs to gas-rich galaxies at high redshift. • Insufficient star formation(some) GALEX ...
the first three thresholds - McGraw
... of the planets, the fact that each year their orbits seem briefly to go into reverse. Copernicus showed that if Earth were orbiting the sun, along with all the other planets, this is exactly what you would expect to see. Furthermore, a German astronomer, Johannes Kepler (1571–1630), demonstrated tha ...
... of the planets, the fact that each year their orbits seem briefly to go into reverse. Copernicus showed that if Earth were orbiting the sun, along with all the other planets, this is exactly what you would expect to see. Furthermore, a German astronomer, Johannes Kepler (1571–1630), demonstrated tha ...
Carbon Enhanced Stars in the Sloan Digital Sky Survey ( SDSS )
... Now we are ready for the science From the SDSS spectra 1. [C/Fe] versus [Fe/H] 2. [alpha/Fe] versus [Fe/H] 3. s-process and C abundance 4. relative frequency of s-process rich and no n- enrichment How they are distributed in metallicity ...
... Now we are ready for the science From the SDSS spectra 1. [C/Fe] versus [Fe/H] 2. [alpha/Fe] versus [Fe/H] 3. s-process and C abundance 4. relative frequency of s-process rich and no n- enrichment How they are distributed in metallicity ...
STScI 2005
... • Stars with M>150 M can only be observed in clusters with total stellar mass >104 M. • This requirement limits the potential sample of stellar clusters that can constrain the upper mass limit to only a few in the Galaxy. ...
... • Stars with M>150 M can only be observed in clusters with total stellar mass >104 M. • This requirement limits the potential sample of stellar clusters that can constrain the upper mass limit to only a few in the Galaxy. ...
Lithium production by thermohaline mixing in low
... undergo hot bottom burning (HBB, where the base of the convective envelope lies in the top of the hydrogen-burning shell). Such stars would be rich in nitrogen, not carbon. These observations suggest that something is missing from the AGB models and an extra mixing mechanism must be at work. Lithium ...
... undergo hot bottom burning (HBB, where the base of the convective envelope lies in the top of the hydrogen-burning shell). Such stars would be rich in nitrogen, not carbon. These observations suggest that something is missing from the AGB models and an extra mixing mechanism must be at work. Lithium ...
Stellar Physics - support material
... 330,000 times that of the Earth. Other stars range in size from roughly 0.08M Sun to 150M Sun . The most numerous stars are the smallest, with only a (relatively) few high mass stars in existence. No stars with masses outside this range have been found. Why should this be? Stars with a mass greater ...
... 330,000 times that of the Earth. Other stars range in size from roughly 0.08M Sun to 150M Sun . The most numerous stars are the smallest, with only a (relatively) few high mass stars in existence. No stars with masses outside this range have been found. Why should this be? Stars with a mass greater ...
4.1 Introduction 4.2 Visual Binaries
... the angle of inclination i. This can be deduced by careful observation of the centre of mass which, as shown in Figure 4.3, will not coincide with the the focus of the projected ellipse. The geometry of the true ellipse may be determined by comparing the observed stellar positions with mathematical ...
... the angle of inclination i. This can be deduced by careful observation of the centre of mass which, as shown in Figure 4.3, will not coincide with the the focus of the projected ellipse. The geometry of the true ellipse may be determined by comparing the observed stellar positions with mathematical ...
2017 Maryland Regional
... 42. __ The minimum-energy arrangement of the neutronized nuclei in the star must result in some neutrons being found outside of the nuclei__ 43. __ Classical novae are a result of fusion and detonation of hydrogen on the surface of the accretor, whereas dwarf novae are thought to be caused by instab ...
... 42. __ The minimum-energy arrangement of the neutronized nuclei in the star must result in some neutrons being found outside of the nuclei__ 43. __ Classical novae are a result of fusion and detonation of hydrogen on the surface of the accretor, whereas dwarf novae are thought to be caused by instab ...
AH Additional notes on stellar physics
... 330,000 times that of the Earth. Other stars range in size from roughly 0.08M Sun to 150M Sun . The most numerous stars are the smallest, with only a (relatively) few high mass stars in existence . No stars with masses outside this range have been found. Why should this be? Stars with a mass greater ...
... 330,000 times that of the Earth. Other stars range in size from roughly 0.08M Sun to 150M Sun . The most numerous stars are the smallest, with only a (relatively) few high mass stars in existence . No stars with masses outside this range have been found. Why should this be? Stars with a mass greater ...
In Pictures: Journey to the Stars
... In the Milky Way Galaxy alone, there are hundreds of billions of stars. And there are many more in the universe. But did you know that a long, long time ago, there were no stars at all? Gravity is the force of attraction between all objects in the © AMNH Universe. Objects with more mass have greater ...
... In the Milky Way Galaxy alone, there are hundreds of billions of stars. And there are many more in the universe. But did you know that a long, long time ago, there were no stars at all? Gravity is the force of attraction between all objects in the © AMNH Universe. Objects with more mass have greater ...
The first carbon-enhanced metal-poor star found in the Sculptor
... The origin of carbon-enhanced metal-poor (CEMP) stars and their possible connection with the chemical elements produced by the first stellar generation is still highly debated. In contrast to the Galactic halo, not many CEMP stars have been found in the dwarf spheroidal galaxies around the Milky Way ...
... The origin of carbon-enhanced metal-poor (CEMP) stars and their possible connection with the chemical elements produced by the first stellar generation is still highly debated. In contrast to the Galactic halo, not many CEMP stars have been found in the dwarf spheroidal galaxies around the Milky Way ...
Energy in The Universe - Physics Department, Princeton University
... are the oldest. They condensed out of the primeval galaxy while it was still in a state of free fall, before it encountered the spin hangup. After the spin hangup the galaxy settled down into a disk, and the ordinary stars were formed in orbits within the disk, where they have re mained ever since. ...
... are the oldest. They condensed out of the primeval galaxy while it was still in a state of free fall, before it encountered the spin hangup. After the spin hangup the galaxy settled down into a disk, and the ordinary stars were formed in orbits within the disk, where they have re mained ever since. ...
Vibrational instability of Population III very massive mainsequence
... For the zero-metallicity stars, the only possible way of starting hydrogen burning is the pp-chain no matter how massive the star is. Hence, the temperature near the stellar centre is much higher than in the case of metal-rich stars. During the pre-main-sequence stage, gravitational contraction rele ...
... For the zero-metallicity stars, the only possible way of starting hydrogen burning is the pp-chain no matter how massive the star is. Hence, the temperature near the stellar centre is much higher than in the case of metal-rich stars. During the pre-main-sequence stage, gravitational contraction rele ...
Chapter 7
... will discuss (b) in Chapter 5. In the present chapter we will discuss the thermal processes that happened in the early Universe and how they created the initial abundances of the elements in our Universe. ...
... will discuss (b) in Chapter 5. In the present chapter we will discuss the thermal processes that happened in the early Universe and how they created the initial abundances of the elements in our Universe. ...
Cosmology – The Origin and Evolution of the Universe
... everything around us was part of the Big Bang, and it all carries clues… ...
... everything around us was part of the Big Bang, and it all carries clues… ...
Physics 3 - Bangor University
... The mechanisms and processes involved when earthquakes occur are extremely complex. However some of the characteristics of earthquakes can be explained: ...
... The mechanisms and processes involved when earthquakes occur are extremely complex. However some of the characteristics of earthquakes can be explained: ...
black hole - Purdue Physics
... The amount of energy released is so great, that most of the elements heavier than Fe are instantly created ...
... The amount of energy released is so great, that most of the elements heavier than Fe are instantly created ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.