Introduction to Galaxies and Cosmology Exercises 2
... At what rate Ṁ would a supermassive black hole have to swallow mass to produce the luminosity L = 1040 W = 2.5 · 1013 L⊙ . Convert your answer to solar masses per year. 8. A quasar has a total luminosity of 1012 L⊙ . a) If 10% of the restmass can be converted to energy, at what rate does it accrete ...
... At what rate Ṁ would a supermassive black hole have to swallow mass to produce the luminosity L = 1040 W = 2.5 · 1013 L⊙ . Convert your answer to solar masses per year. 8. A quasar has a total luminosity of 1012 L⊙ . a) If 10% of the restmass can be converted to energy, at what rate does it accrete ...
distant stars nearby star parallax angle The principle of geometrical
... star, or simply because it’s unusually close by? What about Betelgeuse in Orion? If we didn’t know the distances to these stars, we wouldn’t know that Betelgeuse is a red giant star, with a much greater intrinsic brightness than Vega (and much larger diameter). Nor would we know that many stars visi ...
... star, or simply because it’s unusually close by? What about Betelgeuse in Orion? If we didn’t know the distances to these stars, we wouldn’t know that Betelgeuse is a red giant star, with a much greater intrinsic brightness than Vega (and much larger diameter). Nor would we know that many stars visi ...
SPECTRAL ANALYSIS OF A NEWLY DISCOVERED HgMn STAR
... temperatures range between 10500-15000 K and their photospheres exhibit overabundance of some elements: Sc, Cr,, Mn, Ga, Sr, Y, Zr, Ba, Ce, and Hg [3]. They may also have extreme overabundances of heavy elements such as W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, or Bi [4]. ...
... temperatures range between 10500-15000 K and their photospheres exhibit overabundance of some elements: Sc, Cr,, Mn, Ga, Sr, Y, Zr, Ba, Ce, and Hg [3]. They may also have extreme overabundances of heavy elements such as W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, or Bi [4]. ...
Name
... Hipparchus grouped stars according to their brightness or magnitude. He called the twenty brightest stars first magnitude stars. Stars half that bright were second magnitude. Third magnitude stars were half as bright as second magnitude stars, and so on. Modern astronomers have changed Hipparchus’s ...
... Hipparchus grouped stars according to their brightness or magnitude. He called the twenty brightest stars first magnitude stars. Stars half that bright were second magnitude. Third magnitude stars were half as bright as second magnitude stars, and so on. Modern astronomers have changed Hipparchus’s ...
32Brightness
... source, where discrete colors are absorbed by atoms – From emission and absorption lines, get composition of objects and also their temperature ...
... source, where discrete colors are absorbed by atoms – From emission and absorption lines, get composition of objects and also their temperature ...
Slide 1
... more stars in a region only 30 light years across, which suggests that all the stars were born in a single episode of star formation. Based on optical properties such as brightness and color some of the normal stars in the cluster are known to have masses of about 40 suns. ...
... more stars in a region only 30 light years across, which suggests that all the stars were born in a single episode of star formation. Based on optical properties such as brightness and color some of the normal stars in the cluster are known to have masses of about 40 suns. ...
Document
... Astrophysicists have found this relationship to hold, for example, between the atomic weight of a chemical element and its abundance in the solar system: by and large, the heavier the element, the scarcer it is. Thus, for every trillion atoms of hydrogen (atomic weight 1) there are 100 million atoms ...
... Astrophysicists have found this relationship to hold, for example, between the atomic weight of a chemical element and its abundance in the solar system: by and large, the heavier the element, the scarcer it is. Thus, for every trillion atoms of hydrogen (atomic weight 1) there are 100 million atoms ...
Origin of close binary systems
... - example: the multiplicities of the Orion Trapezium stars and the companion star frequency of high-mass vs. low-mass stars - SPH simulations: hierarchical star cluster formation and the merging of subclusters as a model for the origin of Trapezia - origin due to formation or early dynamical N-body ...
... - example: the multiplicities of the Orion Trapezium stars and the companion star frequency of high-mass vs. low-mass stars - SPH simulations: hierarchical star cluster formation and the merging of subclusters as a model for the origin of Trapezia - origin due to formation or early dynamical N-body ...
Stars
... Galaxies moving away from us would have their light waves stretched out and the spectrum would shift to the red end. Galaxies moving toward us would have their light waves compressed and the spectrum would shift to the blue end. ...
... Galaxies moving away from us would have their light waves stretched out and the spectrum would shift to the red end. Galaxies moving toward us would have their light waves compressed and the spectrum would shift to the blue end. ...
Wien`s Law and Temperature
... the surface temperature of each of these stars. Be careful, real stars don’t have the perfect curves that were shown on the blackbody simulation. Fill in the table below for the temperature estimate for each star. If the peak wavelength is not on the spectra graph for the star, state whether it is o ...
... the surface temperature of each of these stars. Be careful, real stars don’t have the perfect curves that were shown on the blackbody simulation. Fill in the table below for the temperature estimate for each star. If the peak wavelength is not on the spectra graph for the star, state whether it is o ...
ESA-ESO Working Group on the Galaxy
... •Low surface brightness -> need to go as far down on RGB •Need to follow stream across large area on the sky -> Wide-field, accurate RV, faint magnitudes, multiplex ~ 100 ...
... •Low surface brightness -> need to go as far down on RGB •Need to follow stream across large area on the sky -> Wide-field, accurate RV, faint magnitudes, multiplex ~ 100 ...
universe - Northwest ISD Moodle
... surrounding space. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. It is this remnant, or stellar “dust” which has the potential to form new stars and even planets. ...
... surrounding space. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. It is this remnant, or stellar “dust” which has the potential to form new stars and even planets. ...
Spectral-Type Trends: Absorption
... Shown above on the left are the x-ray spectra of six O stars (and one B star) from the Chandra archive, arranged in order of decreasing surface temperature and mass-loss rate. As is evident from the data, the more luminous stars have stronger emission at short wavelengths. One possible explanation f ...
... Shown above on the left are the x-ray spectra of six O stars (and one B star) from the Chandra archive, arranged in order of decreasing surface temperature and mass-loss rate. As is evident from the data, the more luminous stars have stronger emission at short wavelengths. One possible explanation f ...
Accretion Disk
... timescale. The result will be common envelope evolution, in which • The energy released from the orbit will be greater than the binding energy of the envelope. The envelope will be ejected in all directions (but preferentially in the plane of the orbit). • The system’s semi-major axis will shrink ...
... timescale. The result will be common envelope evolution, in which • The energy released from the orbit will be greater than the binding energy of the envelope. The envelope will be ejected in all directions (but preferentially in the plane of the orbit). • The system’s semi-major axis will shrink ...
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.