Electromagnetic Radiation from the Sun
... 6. Why is information about many stars contained in absorption rather than emission spectra? If there is a cloud of gas at a cooler temperature directly between a denser source producing a continuous spectrum (i.e. a star) and a telescope, the gas will absorb light at specific wavelengths that are ...
... 6. Why is information about many stars contained in absorption rather than emission spectra? If there is a cloud of gas at a cooler temperature directly between a denser source producing a continuous spectrum (i.e. a star) and a telescope, the gas will absorb light at specific wavelengths that are ...
Fingerprints in Starlight: Spectroscopy of Stars Inquiry Questions
... atoms in cool stars only have electrons in the ground state. Very hot stars contain hydrogen that that is either ionized or with electrons excited to higher energy levels. In both cases the stars will have weak Balmer absorption lines. 6. Why is information about many stars contained in absorption ...
... atoms in cool stars only have electrons in the ground state. Very hot stars contain hydrogen that that is either ionized or with electrons excited to higher energy levels. In both cases the stars will have weak Balmer absorption lines. 6. Why is information about many stars contained in absorption ...
The Family of Stars
... that a star would have if it were at a distance of 10 pc. If we know a star’s absolute magnitude, we can infer its distance by comparing absolute and apparent magnitudes. ...
... that a star would have if it were at a distance of 10 pc. If we know a star’s absolute magnitude, we can infer its distance by comparing absolute and apparent magnitudes. ...
Stellar Evolution and the Herzsprung-Russell Diagram
... • Requires no energy source – keeps working as the star cools • Star maintains constant radius (about same as Earth) • Example: Sirius B • Maximum mass 1.4 Msun or collapse! ...
... • Requires no energy source – keeps working as the star cools • Star maintains constant radius (about same as Earth) • Example: Sirius B • Maximum mass 1.4 Msun or collapse! ...
The Life of Stars
... blood, and the carbon in our apple pies were all made in the interior of collapsing stars. We are made of ...
... blood, and the carbon in our apple pies were all made in the interior of collapsing stars. We are made of ...
Support worksheet – Topic 3 Questions
... double the distance from Earth to star Y. Calculate the ratio of luminosities X . LY ...
... double the distance from Earth to star Y. Calculate the ratio of luminosities X . LY ...
Variable Stars: Pulsation, Evolution and applications to Cosmology
... Thus a plot of apparent magnitude against color, say B-V (a Color-Magnitude diagram) is like plotting temperature against luminosity ( An HR diagram). Pleiades and Hyades clusters. Globular clusters: tight collection of many, 10,000-100,000 stars: cant resolve stars in the center. All stars in a GC ...
... Thus a plot of apparent magnitude against color, say B-V (a Color-Magnitude diagram) is like plotting temperature against luminosity ( An HR diagram). Pleiades and Hyades clusters. Globular clusters: tight collection of many, 10,000-100,000 stars: cant resolve stars in the center. All stars in a GC ...
Lecture 13 - Main Sequence Stars
... • We have been focusing on the properties of stars on the main sequence, but the chemical composition of stars change with time as the star burns hydrogen into helium. • This causes the other properties to change with time and we can track these changes via motion of the star in the HR diagram. ...
... • We have been focusing on the properties of stars on the main sequence, but the chemical composition of stars change with time as the star burns hydrogen into helium. • This causes the other properties to change with time and we can track these changes via motion of the star in the HR diagram. ...
The Hertzsprung-Russell Diagram
... The Hertzsprung-Russell Diagram Hertzsprung and Russell had the idea of plotting the luminosity of a star against its spectral type. This works best for a cluster, where you know the stars are all at the same distance. Then apparent brightness vs spectral type is basically the same as luminosity vs ...
... The Hertzsprung-Russell Diagram Hertzsprung and Russell had the idea of plotting the luminosity of a star against its spectral type. This works best for a cluster, where you know the stars are all at the same distance. Then apparent brightness vs spectral type is basically the same as luminosity vs ...
and Concept Self-test (1,2,3,5,6,7,8,9)
... Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth. Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our Sun. After these stars have finished ...
... Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth. Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our Sun. After these stars have finished ...
STARS
... • An enormous explosion when a large star dies. • When all the hydrogen is used up the core collapses • The absence of pressure causes a neutron star or a black hole. • The explosion can be bright enough to see during the day! ...
... • An enormous explosion when a large star dies. • When all the hydrogen is used up the core collapses • The absence of pressure causes a neutron star or a black hole. • The explosion can be bright enough to see during the day! ...
Chapter19
... The most massive main sequence stars are about 20 times as hot, 600 times as massive, 150 times as large, and a billion times as luminous as the least massive main sequence stars. Less massive stars become degenerate and stop heating up before hydrogen fusion can begin. During the next 5 billion yea ...
... The most massive main sequence stars are about 20 times as hot, 600 times as massive, 150 times as large, and a billion times as luminous as the least massive main sequence stars. Less massive stars become degenerate and stop heating up before hydrogen fusion can begin. During the next 5 billion yea ...
Star Lifecycle
... A star is a really hot ball of gas, with hydrogen fusing into helium at its core. Stars produce light energy, heat energy, and electromagnetic waves. Stars spend the majority of their lives fusing hydrogen, and when the hydrogen fuel is gone, stars fuse helium into carbon. The more massive s ...
... A star is a really hot ball of gas, with hydrogen fusing into helium at its core. Stars produce light energy, heat energy, and electromagnetic waves. Stars spend the majority of their lives fusing hydrogen, and when the hydrogen fuel is gone, stars fuse helium into carbon. The more massive s ...
Star Life Cycle
... When a star has burned between 10% and 20% of its hydrogen, its core will to run out of fuel. At this stage, the star is entering the end of its life. The diameter of the star can increase by a factor of 200, while its cooling is translated into a reddening of its radiation : the star is becoming wh ...
... When a star has burned between 10% and 20% of its hydrogen, its core will to run out of fuel. At this stage, the star is entering the end of its life. The diameter of the star can increase by a factor of 200, while its cooling is translated into a reddening of its radiation : the star is becoming wh ...
star
... temperature, color, and absolute brightness of a sample of stars. They are used to estimate the sizes of stars and their distances, and infer how stars change over time. If two stars a ...
... temperature, color, and absolute brightness of a sample of stars. They are used to estimate the sizes of stars and their distances, and infer how stars change over time. If two stars a ...
Document
... Mizar, 88 light years distant, is the middle star in the handle of the Big Dipper. It was the first binary star system to be imaged with a telescope. Spectroscopic observations show periodic Doppler shifts in the spectra of Mizar A and B, indicating that they are each binary stars. But they were too ...
... Mizar, 88 light years distant, is the middle star in the handle of the Big Dipper. It was the first binary star system to be imaged with a telescope. Spectroscopic observations show periodic Doppler shifts in the spectra of Mizar A and B, indicating that they are each binary stars. But they were too ...
Stars
... Mizar, 88 light years distant, is the middle star in the handle of the Big Dipper. It was the first binary star system to be imaged with a telescope. Spectroscopic observations show periodic Doppler shifts in the spectra of Mizar A and B, indicating that they are each binary stars. But they were too ...
... Mizar, 88 light years distant, is the middle star in the handle of the Big Dipper. It was the first binary star system to be imaged with a telescope. Spectroscopic observations show periodic Doppler shifts in the spectra of Mizar A and B, indicating that they are each binary stars. But they were too ...
The Universe
... A star’s stable phase ends when most of its hydrogen has been consumed by fusion. The reduction in fusion causes the core to cool. This lowers the pressure causing the star to collapse upon itself under its own gravity. As the outer layers contract, they heat up. This triggers the fusion of the rema ...
... A star’s stable phase ends when most of its hydrogen has been consumed by fusion. The reduction in fusion causes the core to cool. This lowers the pressure causing the star to collapse upon itself under its own gravity. As the outer layers contract, they heat up. This triggers the fusion of the rema ...
Life Cycle of a Star
... • A contracting cloud of gas and dust • Pressure and heat start nuclear fusion ...
... • A contracting cloud of gas and dust • Pressure and heat start nuclear fusion ...
Our Star - the Sun
... • Most brown dwarfs are in even cooler spectral classes called L and T • Unlike true stars, brown dwarfs are too small to ...
... • Most brown dwarfs are in even cooler spectral classes called L and T • Unlike true stars, brown dwarfs are too small to ...
Star
A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.