Gamma-Ray Bursts
... gamma-ray photons, the most energetic form of light, release as much energy in their short duration as our Sun will in its entire lifetime. Two classes of GRBs have been identified, with a dividing line in the gamma-ray emission duration of about 2 seconds.The shorter events are thought to beassocia ...
... gamma-ray photons, the most energetic form of light, release as much energy in their short duration as our Sun will in its entire lifetime. Two classes of GRBs have been identified, with a dividing line in the gamma-ray emission duration of about 2 seconds.The shorter events are thought to beassocia ...
Astronomy (stars, galaxies and the Universe)
... Groups of stars that form a pattern The revolution of the Earth around the Sun cause different constellations to be seen at different times of the year Stars located above the north and south poles, called circumpolar stars, appear to move in circles above the horizon each night Astronomers use cons ...
... Groups of stars that form a pattern The revolution of the Earth around the Sun cause different constellations to be seen at different times of the year Stars located above the north and south poles, called circumpolar stars, appear to move in circles above the horizon each night Astronomers use cons ...
4. Star Formation
... It is now well established that stars form from gas and dust in the ISM. Young stars and massive stars are preferably found close to/within molecular clouds. This obscuration hence requires observations at infrared, millimetre, or radio wavelength. The problems of star formation: Create a star (radi ...
... It is now well established that stars form from gas and dust in the ISM. Young stars and massive stars are preferably found close to/within molecular clouds. This obscuration hence requires observations at infrared, millimetre, or radio wavelength. The problems of star formation: Create a star (radi ...
Astronomy Activity word document
... 9. Click on “Development” on the right hand column. Just like living organisms, stars have a __________________________. 10. Stars are born from huge clouds of _________________ and _________________. 11. What is a Nebula? _____________________________________________________________________ _______ ...
... 9. Click on “Development” on the right hand column. Just like living organisms, stars have a __________________________. 10. Stars are born from huge clouds of _________________ and _________________. 11. What is a Nebula? _____________________________________________________________________ _______ ...
Integrative Studies 410 Our Place in the Universe
... as far as we can see Cepheids – about 50 million ly • In 1920 Hubble used this technique to measure the distance to Andromeda (about 2 million ly) • Works best for periodic variables ...
... as far as we can see Cepheids – about 50 million ly • In 1920 Hubble used this technique to measure the distance to Andromeda (about 2 million ly) • Works best for periodic variables ...
Stellar Luminosity and Mass Functions * * * * * History and
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
Week 9 notes
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
Supercomputer simulation provides missing link between turbulence, hypernovae and gamma-ray bursts
... California Institute of Technology. “But if a star is spinning this fast, then there is a lot of energy in the rotation. The problem has been how to extract that and dump it into the explosion.” Creating ultra-strong magnetic fields A core-collapse supernova occurs when hydrogen fusion in the core – ...
... California Institute of Technology. “But if a star is spinning this fast, then there is a lot of energy in the rotation. The problem has been how to extract that and dump it into the explosion.” Creating ultra-strong magnetic fields A core-collapse supernova occurs when hydrogen fusion in the core – ...
Layers of the Sun (~ 75% Hydrogen ~ 25% Helium)
... Solar energy is created deep within the core of the Sun. It is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth's air pressure at sea level) is so intense that nuclear reactions take place. This reaction causes four protons or hydrogen nuclei to fuse tog ...
... Solar energy is created deep within the core of the Sun. It is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth's air pressure at sea level) is so intense that nuclear reactions take place. This reaction causes four protons or hydrogen nuclei to fuse tog ...
Mon Oct 28, 2013 MOON AND MARS IN PREDAWN SKY Tonight
... not a particularly bright star – if you didn’t know just where to look for it, you’d probably not even notice it. But it is quite an unusual star – three stars, actually. The name Algol derives from its arabic designation as “the head of the demon,” and is also the basis of the word, “ghoul.” Algol ...
... not a particularly bright star – if you didn’t know just where to look for it, you’d probably not even notice it. But it is quite an unusual star – three stars, actually. The name Algol derives from its arabic designation as “the head of the demon,” and is also the basis of the word, “ghoul.” Algol ...
1_Introduction
... “Far away” = at a distance larger than 206,000 times the diameter of a star. 206,000 × Sun’s diameter = 290 billion kilometers = 11 light-days ...
... “Far away” = at a distance larger than 206,000 times the diameter of a star. 206,000 × Sun’s diameter = 290 billion kilometers = 11 light-days ...
Variables, Star Clusters, and Nebulae (Professor Powerpoint)
... Cepheid variables are type F to type K supergiants yellow in color, pulsating stars, and relatively rare. •Average Temperature = 4000 to 8000 Kelvin •Average Luminosity = 300 to 40,000 Lsun ...
... Cepheid variables are type F to type K supergiants yellow in color, pulsating stars, and relatively rare. •Average Temperature = 4000 to 8000 Kelvin •Average Luminosity = 300 to 40,000 Lsun ...
Stars & Constellations
... the North Star (which always points North). Once navigators had found North, they could observe its height in the sky and hence work out their latitude (how far North / South they are). Now they know how far North they are + the direction they’re traveling ...
... the North Star (which always points North). Once navigators had found North, they could observe its height in the sky and hence work out their latitude (how far North / South they are). Now they know how far North they are + the direction they’re traveling ...
answers
... distant objects ever found. All of the objects are galaxies of stars except for E, which is a single nearby star. Which object is more luminous? A) E B) F C) they are about the same B) The two objects look equally bright, but are very different. The star is much closer and much less luminous. The ga ...
... distant objects ever found. All of the objects are galaxies of stars except for E, which is a single nearby star. Which object is more luminous? A) E B) F C) they are about the same B) The two objects look equally bright, but are very different. The star is much closer and much less luminous. The ga ...
B2 MOCK EXAM LISTENING COMPREHENSION I. Listen to a talk
... population. In effect, new areas of habitat have been opened up. ______________________ The one of 1963 had a notable impact, but surprisingly there is little to suggest that the same happened in the freezing temperatures of 1979 and 1892. _____________________ As well as the UK, similar increases h ...
... population. In effect, new areas of habitat have been opened up. ______________________ The one of 1963 had a notable impact, but surprisingly there is little to suggest that the same happened in the freezing temperatures of 1979 and 1892. _____________________ As well as the UK, similar increases h ...
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.