Practice Exam for 3 rd Astronomy Exam
... hydrogen are known as HII regions and they are the signature of a star forming region – meaning that the presence of an HII region signifies to astronomers that stars are forming there. The reason is HII regions signify a star forming region is that the OB Association, which are composed of the firs ...
... hydrogen are known as HII regions and they are the signature of a star forming region – meaning that the presence of an HII region signifies to astronomers that stars are forming there. The reason is HII regions signify a star forming region is that the OB Association, which are composed of the firs ...
Oct 06, 2001
... C) It is a shell of gas ejected from a star late in its life. D) It is what is left when a white dwarf star explodes as a supernova. 8) What makes a high-mass star's core collapse? A) Energy from its outer layers compresses its core. B) The only thing that can make a star's core collapse is a collis ...
... C) It is a shell of gas ejected from a star late in its life. D) It is what is left when a white dwarf star explodes as a supernova. 8) What makes a high-mass star's core collapse? A) Energy from its outer layers compresses its core. B) The only thing that can make a star's core collapse is a collis ...
Stars, Galaxies, and the Universe Section 1 Section 1
... stars. The sun has a diameter of 1,390,000 km. • Most of the stars you can see in the night sky are medium-sized stars. • Many stars also have about the same mass as the sun, however some stars may be more or less massive. ...
... stars. The sun has a diameter of 1,390,000 km. • Most of the stars you can see in the night sky are medium-sized stars. • Many stars also have about the same mass as the sun, however some stars may be more or less massive. ...
AST 207 7 Homew
... Since color is relateed to temperrature, the temperratures are thee same. nitudes is two o steps 5 magn of 2.5 mag, which is i two factorss of 10 in lumino osity, or 102, or o 100. So if lu uminosity (L)) increasses by a facto or of 100, an nd temperaturre (T) stays constant, c then n using , 100 = ...
... Since color is relateed to temperrature, the temperratures are thee same. nitudes is two o steps 5 magn of 2.5 mag, which is i two factorss of 10 in lumino osity, or 102, or o 100. So if lu uminosity (L)) increasses by a facto or of 100, an nd temperaturre (T) stays constant, c then n using , 100 = ...
ASTR 1101-001 Spring 2008 - Louisiana State University
... (imperial astronomer to the Chinese court) made a startling discovery. Just a few minutes before sunrise, a new and dazzling object ascended above the eastern horizon. This “guest star” was so brilliant that it could easily be seen during broad daylight for the rest of July! This “guest star” was vi ...
... (imperial astronomer to the Chinese court) made a startling discovery. Just a few minutes before sunrise, a new and dazzling object ascended above the eastern horizon. This “guest star” was so brilliant that it could easily be seen during broad daylight for the rest of July! This “guest star” was vi ...
Chapter 12 - Indiana State University
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
Question Paper - SAVE MY EXAMS!
... 10 α-Centauri is one of the nearest stars to our Sun. The surface temperatures of these two stars are about the same. α-Centauri has a 20% greater diameter than the Sun. The ratio of the luminosity of α-Centauri to the luminosity of the Sun is about A 1.2 B 1.4 C 1.7 D 2.1 (Total for Question = 1 ...
... 10 α-Centauri is one of the nearest stars to our Sun. The surface temperatures of these two stars are about the same. α-Centauri has a 20% greater diameter than the Sun. The ratio of the luminosity of α-Centauri to the luminosity of the Sun is about A 1.2 B 1.4 C 1.7 D 2.1 (Total for Question = 1 ...
Whiteq
... mass of the sun. However, it is believed that the progenitor star can be as much as 4 times as massive as the sun, because during the end of their nuclear fuel burning stage most stars eject a large portion of their mass. In the case of low mass stars, this leads to a planetary nebula. A small minor ...
... mass of the sun. However, it is believed that the progenitor star can be as much as 4 times as massive as the sun, because during the end of their nuclear fuel burning stage most stars eject a large portion of their mass. In the case of low mass stars, this leads to a planetary nebula. A small minor ...
The Cosmic Perspective Star Stuff
... d) Stars would continue burning heavier and heavier elements and the universe would have far more lead and uranium. e) Stars would be much less dense, and therefore larger, but otherwise the same. © 2014 Pearson Education, Inc. ...
... d) Stars would continue burning heavier and heavier elements and the universe would have far more lead and uranium. e) Stars would be much less dense, and therefore larger, but otherwise the same. © 2014 Pearson Education, Inc. ...
Astronomy - Scioly.org
... 52. Why can't the lowest-mass stars become giants? a. They never get hot enough for the triple-alpha process. b. Their gravity is too weak to stop them from expanding beyond the giant phase. c. They live so long that none has ever left the main sequence. d. The rate of hydrogen-shell fusion is too s ...
... 52. Why can't the lowest-mass stars become giants? a. They never get hot enough for the triple-alpha process. b. Their gravity is too weak to stop them from expanding beyond the giant phase. c. They live so long that none has ever left the main sequence. d. The rate of hydrogen-shell fusion is too s ...
center of mass
... 7. The absolute magnitude of any star is equal to its apparent magnitude at a distance of 10 parsecs. Use this definition, how light intensity changes with distance, and how the stellar magnitude system is set up to determine the following. If a star's apparent visual magnitude is less than its abso ...
... 7. The absolute magnitude of any star is equal to its apparent magnitude at a distance of 10 parsecs. Use this definition, how light intensity changes with distance, and how the stellar magnitude system is set up to determine the following. If a star's apparent visual magnitude is less than its abso ...
Chapter 09
... 7. The absolute magnitude of any star is equal to its apparent magnitude at a distance of 10 parsecs. Use this definition, how light intensity changes with distance, and how the stellar magnitude system is set up to determine the following. If a star's apparent visual magnitude is less than its abso ...
... 7. The absolute magnitude of any star is equal to its apparent magnitude at a distance of 10 parsecs. Use this definition, how light intensity changes with distance, and how the stellar magnitude system is set up to determine the following. If a star's apparent visual magnitude is less than its abso ...
Chapter 6 Stars
... are the remains of high-mass stars. They are even smaller and denser than white dwarfs. A neutron star may contain as much as three times the mass of the sun but be only about 25 kilometers in diameter, the size of a city! In 1967, Jocelyn Bell, a British astronomy student, detected an object in spa ...
... are the remains of high-mass stars. They are even smaller and denser than white dwarfs. A neutron star may contain as much as three times the mass of the sun but be only about 25 kilometers in diameter, the size of a city! In 1967, Jocelyn Bell, a British astronomy student, detected an object in spa ...
June 2017
... Fig. 1: The variation of intensity of emitted radiation with wavelength It can be seen that the intensity (a measure of the number of photons per unit area per second) is not uniform across the range but peaks at a specific wavelength value (λmax) which depends on the temperature of the object. Towa ...
... Fig. 1: The variation of intensity of emitted radiation with wavelength It can be seen that the intensity (a measure of the number of photons per unit area per second) is not uniform across the range but peaks at a specific wavelength value (λmax) which depends on the temperature of the object. Towa ...
Stellar Populations of Galaxies- 2 Lectures H
... the M-S for a long time On the M-S hydrogen burning' nuclear fusion in the core generates energy, the pressure is balanced by gravityhydrostatic equilibrium. Stars spend ~80% of their lifetime on the M-S fusing hydrogen into helium. The position in the HR diagram changes with time, e.g. the Sun will ...
... the M-S for a long time On the M-S hydrogen burning' nuclear fusion in the core generates energy, the pressure is balanced by gravityhydrostatic equilibrium. Stars spend ~80% of their lifetime on the M-S fusing hydrogen into helium. The position in the HR diagram changes with time, e.g. the Sun will ...
Stars change over their life cycles.
... The collapsed core of a supergiant star may form an extremely dense body called a neutron star. Neutron stars measure only about 20 kilometers (12 mi) in diameter, but their masses are one to three times that of the Sun. Neutron stars emit little visible light. However, they strongly emit other form ...
... The collapsed core of a supergiant star may form an extremely dense body called a neutron star. Neutron stars measure only about 20 kilometers (12 mi) in diameter, but their masses are one to three times that of the Sun. Neutron stars emit little visible light. However, they strongly emit other form ...
Level 2 Science (90764) 2011 Assessment Schedule
... the hydrogen nuclei to fuse and release energy and luminance like the Sun (electromagnetic radiation). On the other hand a brown dwarf has insufficient mass to start fusion process of hydrogen nuclei. Brown dwarfs are small in comparison to the sun and (emit only infra-red radiation). No luminosity. ...
... the hydrogen nuclei to fuse and release energy and luminance like the Sun (electromagnetic radiation). On the other hand a brown dwarf has insufficient mass to start fusion process of hydrogen nuclei. Brown dwarfs are small in comparison to the sun and (emit only infra-red radiation). No luminosity. ...
Ia 超新星的
... high enough to induce any substantial nuclear reactions. This isolated dead star can exist almost indefinitely, slowly cooling down to black dwarf as it radiates its energy into space. No supernova explosion will ensue. A very different fate awaits a WD that accretes mass from a close binary compani ...
... high enough to induce any substantial nuclear reactions. This isolated dead star can exist almost indefinitely, slowly cooling down to black dwarf as it radiates its energy into space. No supernova explosion will ensue. A very different fate awaits a WD that accretes mass from a close binary compani ...
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.