and mass loss
... • Collapse accelerated by two instabilities: 1. e-captures on Fe-group increase n-rich composition, decrease of ne & Pe, reduce MCh; 2. Photodisintegration increase number a-particles leading to total disintegration; ...
... • Collapse accelerated by two instabilities: 1. e-captures on Fe-group increase n-rich composition, decrease of ne & Pe, reduce MCh; 2. Photodisintegration increase number a-particles leading to total disintegration; ...
Stellar Metamorphosis: The Nearest Star
... Abstract: In stellar metamorphosis humanities’ closest star is the Earth itself. Explanation is provided. In the so-called “established sciences” the closest star to the Earth is the Sun, and the closest star to Earth besides the Sun is Proxima Centauri. This is not complete. According to stellar me ...
... Abstract: In stellar metamorphosis humanities’ closest star is the Earth itself. Explanation is provided. In the so-called “established sciences” the closest star to the Earth is the Sun, and the closest star to Earth besides the Sun is Proxima Centauri. This is not complete. According to stellar me ...
Ch16: The Milky Way
... and velocity) tells us mass within Sun’s orbit: 1.0 x 1011 MSun The total amount of light suggests ~ few x 109 Msun Dark matter! ...
... and velocity) tells us mass within Sun’s orbit: 1.0 x 1011 MSun The total amount of light suggests ~ few x 109 Msun Dark matter! ...
Lecture17
... Last Time: Stars Spectrum of a star tells us much about it. Used to classify stars by type: OBAFKM (from hottest to coldest). All stars have spectra lines or “gaps” in their continuous spectrum, just like the sun, but the lines differ, and depend on how hot the star is. Recently cool stellar types ...
... Last Time: Stars Spectrum of a star tells us much about it. Used to classify stars by type: OBAFKM (from hottest to coldest). All stars have spectra lines or “gaps” in their continuous spectrum, just like the sun, but the lines differ, and depend on how hot the star is. Recently cool stellar types ...
Lecture 6: Properties of Stars The Constellations The Constellations
... o Top right has bright cool stars – Red ...
... o Top right has bright cool stars – Red ...
Stars: Their Life and Afterlife
... mechanism for powering the Sun. After a few thousand years of gravitational contraction, a solar-mass protostar’s surface will reach temperatures of 2000 – 3000 K. Since it is still much larger than the final star, its surface can radiate an immense amount of energy, and the protostar’s luminosity c ...
... mechanism for powering the Sun. After a few thousand years of gravitational contraction, a solar-mass protostar’s surface will reach temperatures of 2000 – 3000 K. Since it is still much larger than the final star, its surface can radiate an immense amount of energy, and the protostar’s luminosity c ...
White dwarfs & supernovae — Oct 19 white dwarfs?
... degrees SE of Thien-kuan. After more than a year it gradually became invisible.−p578. ...
... degrees SE of Thien-kuan. After more than a year it gradually became invisible.−p578. ...
DTU_9e_ch13
... becomes a giant when hydrogen shell fusion begins. It becomes a horizontal-branch star when core helium fusion begins. It enters the asymptotic giant branch and becomes a supergiant when helium shell fusion starts. Stellar winds during the thermal pulse phase eject mass from the star’s outer layers. ...
... becomes a giant when hydrogen shell fusion begins. It becomes a horizontal-branch star when core helium fusion begins. It enters the asymptotic giant branch and becomes a supergiant when helium shell fusion starts. Stellar winds during the thermal pulse phase eject mass from the star’s outer layers. ...
the spectrum of a partially ionized jet sodium ionization in t
... We present the results of a study of the sodium ionization and excitation in the winds of low-luminosity, pre-main-sequence stars. Line profiles for the Nal doublet at 5990,5986 Aare discussed and compared with the observations for those T Tauri stars with P-Cygni profiles. We find that the observed ...
... We present the results of a study of the sodium ionization and excitation in the winds of low-luminosity, pre-main-sequence stars. Line profiles for the Nal doublet at 5990,5986 Aare discussed and compared with the observations for those T Tauri stars with P-Cygni profiles. We find that the observed ...
PHYS3380_102615_bw
... We have observed disks around other stars. These could be new planetary systems in formation. ...
... We have observed disks around other stars. These could be new planetary systems in formation. ...
H-R Diagrams
... 1 The temperature increases from RL. Why? The high temps correspond to small wavelengths, so wavelength increases LR along the x-axis. ...
... 1 The temperature increases from RL. Why? The high temps correspond to small wavelengths, so wavelength increases LR along the x-axis. ...
FRIENDS OF THE PLANETARIUM NEWSLETTER April2002
... hottest. Stars are the same; with the hot 30,000 degree stars being a bluish white in colour and the cold stars like Betelgeuse being red. Our yellow sun lies in between with a surface temperature of around 6000 degrees. Despite its size of at least 160 million suns, its mass is only equivalent to s ...
... hottest. Stars are the same; with the hot 30,000 degree stars being a bluish white in colour and the cold stars like Betelgeuse being red. Our yellow sun lies in between with a surface temperature of around 6000 degrees. Despite its size of at least 160 million suns, its mass is only equivalent to s ...
Topics for this week
... from their lowest energy levels to the next higher level. So cool star have sodium absorption lines. But it isn’t hard to ionize a sodium atom. In hotter stars the sodium atoms are ionized and absorb different energy photons. ...
... from their lowest energy levels to the next higher level. So cool star have sodium absorption lines. But it isn’t hard to ionize a sodium atom. In hotter stars the sodium atoms are ionized and absorb different energy photons. ...
1. - TeacherWeb
... • Some supernovas form neutron stars and black holes. – If the core that remains after a supernova has a mass of 1.4 to 3 solar masses, the remnant can become a neutron star. – If the leftover core has a mass that is greater than three solar masses, it will collapse to form a black hole. • black hol ...
... • Some supernovas form neutron stars and black holes. – If the core that remains after a supernova has a mass of 1.4 to 3 solar masses, the remnant can become a neutron star. – If the leftover core has a mass that is greater than three solar masses, it will collapse to form a black hole. • black hol ...
Sun
... looks like a large ball of light 2. Medium sized star made of hydrogen & helium 3. Source of most energy on Earth 4. Responsible for wind/weather on Earth ...
... looks like a large ball of light 2. Medium sized star made of hydrogen & helium 3. Source of most energy on Earth 4. Responsible for wind/weather on Earth ...
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.