The Interstellar Medium (ISM) The Dust The Gas: a. The Hot
... General properties: Average temperature about 100K and densities about 1–10 atoms/cm3 , typically atomic Hydrogen (HI) and about 1000 dust particles per cubic kilometer! dust about 1% of the mass of the ISM. Composition of ISM: about 90% hydrogen, about 9% helium; about 1% heavier elements ...
... General properties: Average temperature about 100K and densities about 1–10 atoms/cm3 , typically atomic Hydrogen (HI) and about 1000 dust particles per cubic kilometer! dust about 1% of the mass of the ISM. Composition of ISM: about 90% hydrogen, about 9% helium; about 1% heavier elements ...
Neutron Stars
... A star is rotating with = 1 rev/sec. If the core begins wit ha radius equal to the radius of the sun, and collapses to a final radius of 0.01 R, what will its final angular speed become after the collapse? Assume the mass stays a constant. ...
... A star is rotating with = 1 rev/sec. If the core begins wit ha radius equal to the radius of the sun, and collapses to a final radius of 0.01 R, what will its final angular speed become after the collapse? Assume the mass stays a constant. ...
Deducing Temperatures and Luminosities of Stars
... M 2.5 log10 m 10 pc distance 5 log10 m ...
... M 2.5 log10 m 10 pc distance 5 log10 m ...
Astronomy 112: The Physics of Stars Class 3 Notes: Hydrostatic
... shell m = 0 is the one at the center of the star, the one m = M/2 is at the point that contains half the mass of the star, and the shell m = M is the outermost one. Each shell has some particular radius r(m), and we can instead talk about the pressure, temperature, etc. in given mass shell: P (m), T ...
... shell m = 0 is the one at the center of the star, the one m = M/2 is at the point that contains half the mass of the star, and the shell m = M is the outermost one. Each shell has some particular radius r(m), and we can instead talk about the pressure, temperature, etc. in given mass shell: P (m), T ...
EF Eri: Its White Dwarf Primary and L Dwarf Secondary
... magnetic field --> dwarf nova, classical nova, nova-like (IP). These binaries contain an accretion disk. • If the white dwarf has a ~10 to 250MG field --> Polar or AM Herculis type. These contain no accretion disk. ...
... magnetic field --> dwarf nova, classical nova, nova-like (IP). These binaries contain an accretion disk. • If the white dwarf has a ~10 to 250MG field --> Polar or AM Herculis type. These contain no accretion disk. ...
white dwarfs and the age of the universe
... the masses of the hydrogen layer are in the range between 10−8 and 10−4 M⊙ thus indicating that DAs are born with a variety of layer masses. As the DA star cools down, the convective region deepens and, depending on the mass, reaches the helium layer. When this happens, helium is dredged up and the ...
... the masses of the hydrogen layer are in the range between 10−8 and 10−4 M⊙ thus indicating that DAs are born with a variety of layer masses. As the DA star cools down, the convective region deepens and, depending on the mass, reaches the helium layer. When this happens, helium is dredged up and the ...
Active Galaxies and Quasars: the most luminous objects in the
... At the distances estimated from the redshifts of the emission lines, quasars have a luminosity 10 - 10,000x the integrated light of all the stars in the Milky Way. ...
... At the distances estimated from the redshifts of the emission lines, quasars have a luminosity 10 - 10,000x the integrated light of all the stars in the Milky Way. ...
Answers
... speed should have been halved, but was almost the same - 2.58 x 105 m/s vs. 2.47 x 105 m/s. This is the case in every galaxy that has been studied and was completely unexpected by astronomers. There is unseen matter extending way beyond the visible part of the galaxy. Note: The first part of the gra ...
... speed should have been halved, but was almost the same - 2.58 x 105 m/s vs. 2.47 x 105 m/s. This is the case in every galaxy that has been studied and was completely unexpected by astronomers. There is unseen matter extending way beyond the visible part of the galaxy. Note: The first part of the gra ...
Module 6: “The Message of Starlight Assignment 9: Parallax, stellar
... 1. Open the file Nearby_stars_data.xls and make a plot of B-V versus Mv (absolute magnitude) for the stars in the file. To match the plots that astronomers make, please use Mv on the Y axis, with negative numbers increasing up (the magnitude scale is reversed: big numbers are fainter), and B-V on th ...
... 1. Open the file Nearby_stars_data.xls and make a plot of B-V versus Mv (absolute magnitude) for the stars in the file. To match the plots that astronomers make, please use Mv on the Y axis, with negative numbers increasing up (the magnitude scale is reversed: big numbers are fainter), and B-V on th ...
1 Introduction - University of Amsterdam
... spinning massive stars at solar metallicity. The lower panel shows the main-sequence phase, which represents about 90% of the lifetime of the star. The upper panel represents the post main-sequence phases, ignoring the very brief phase after core helium burning. A star of given initial mass moves up ...
... spinning massive stars at solar metallicity. The lower panel shows the main-sequence phase, which represents about 90% of the lifetime of the star. The upper panel represents the post main-sequence phases, ignoring the very brief phase after core helium burning. A star of given initial mass moves up ...
MHD_of_Accretion_Disks
... R Y S Y S T E M Our Sun is unusual in that it is alone - most stars occur in multiple or binary systems. In a binary system, the higher mass star will evolve faster and will eventually become a compact object - either a white dwarf star, a neutron star, or black hole. When the lower mass star later ...
... R Y S Y S T E M Our Sun is unusual in that it is alone - most stars occur in multiple or binary systems. In a binary system, the higher mass star will evolve faster and will eventually become a compact object - either a white dwarf star, a neutron star, or black hole. When the lower mass star later ...
P-process nucleosynthesis in detonating white dwarfs in the light of
... shock wave is formed which rapidly transforms into a detonation due to the fast and energetic nuclear combustion developed at the rear edge of the shock wave. Soon a ChapmannJouguet self-sustained detonation emerged (see for instance Fig. 4 of GSBW). During its journey the substrate of the detonatio ...
... shock wave is formed which rapidly transforms into a detonation due to the fast and energetic nuclear combustion developed at the rear edge of the shock wave. Soon a ChapmannJouguet self-sustained detonation emerged (see for instance Fig. 4 of GSBW). During its journey the substrate of the detonatio ...
Measuring the Properties of Stars - Sierra College Astronomy Home
... Knowledge of the size of one of the star’s ellipses, along with knowledge of the period of its motion, permits calculation of the total mass of the two stars. To determine how the system’s total mass is distributed between the two stars, one need only consider the ratio of the two stars’ distances t ...
... Knowledge of the size of one of the star’s ellipses, along with knowledge of the period of its motion, permits calculation of the total mass of the two stars. To determine how the system’s total mass is distributed between the two stars, one need only consider the ratio of the two stars’ distances t ...
Heyvaerts
... md = mu + me = ms • If quark masses = 0 solution is strange matter no leptons and md = mu = ms In this case Fermi momenta equal, density equal and strange matter neutral without leptons. • Speculation that such matter, once formed, is more stable than ordinary nucleonic matter, even at low pressure ...
... md = mu + me = ms • If quark masses = 0 solution is strange matter no leptons and md = mu = ms In this case Fermi momenta equal, density equal and strange matter neutral without leptons. • Speculation that such matter, once formed, is more stable than ordinary nucleonic matter, even at low pressure ...
VOC 3J-2
... Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. ...
... Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. ...
A Stars
... • Stars are made of hot, dense gas – Continuous spectrum from the lowest visible layers (“photosphere”). – Approximates a blackbody spectrum. ...
... • Stars are made of hot, dense gas – Continuous spectrum from the lowest visible layers (“photosphere”). – Approximates a blackbody spectrum. ...
Stellar Census
... The distribution of the near stars is very different from that of the bright stars The majority of the near stars are cool and faint K- and Mtype stars Only one star in the entire near-star sample is a giant The rest of the nearstar sample are main-sequence stars 22 March 2005 ...
... The distribution of the near stars is very different from that of the bright stars The majority of the near stars are cool and faint K- and Mtype stars Only one star in the entire near-star sample is a giant The rest of the nearstar sample are main-sequence stars 22 March 2005 ...
wdm_shanghai_Mayinzhe
... baryon content, smearing out some DM along with them • But simulations have difficulties in reproducing all properties with single feedback mechanism (e.g. BoylanKolchin+2012; Garrison-Kimmel et al. 2013; Teyssier et ...
... baryon content, smearing out some DM along with them • But simulations have difficulties in reproducing all properties with single feedback mechanism (e.g. BoylanKolchin+2012; Garrison-Kimmel et al. 2013; Teyssier et ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.