IL CIELO COME LABORATORIO – 2010/2011 STAR FORMATION
... difference of about 1 Mpc between the closest and the furthest arm of the galaxy. The mean quantity of ionizing photons is 8·1049, that is also the amount of the ionized gas. The number of stars which belong to O5 spectral class, needed to warm all the ionized gas is nearly 12 stars. In the same way ...
... difference of about 1 Mpc between the closest and the furthest arm of the galaxy. The mean quantity of ionizing photons is 8·1049, that is also the amount of the ionized gas. The number of stars which belong to O5 spectral class, needed to warm all the ionized gas is nearly 12 stars. In the same way ...
Stellar Evolution Task
... During the Planetary Nebula phase the star becomes a white dwarf and ejects all its mass into space. What remains is a white dwarf in the centre and a beautiful symetric nebula. It looks like a ring since the mass the star has lost is in a spherical shell around it. ...
... During the Planetary Nebula phase the star becomes a white dwarf and ejects all its mass into space. What remains is a white dwarf in the centre and a beautiful symetric nebula. It looks like a ring since the mass the star has lost is in a spherical shell around it. ...
printer-friendly version of benchmark
... At this point, the Sun will leave the Main Sequence as the outward pressure from the core decreases and gravitational collapse causes the Sun to contract. As the Sun contracts, the temperature at the core will increase, and when a temperature of around 100,000,000 K has been reached, fusion of heli ...
... At this point, the Sun will leave the Main Sequence as the outward pressure from the core decreases and gravitational collapse causes the Sun to contract. As the Sun contracts, the temperature at the core will increase, and when a temperature of around 100,000,000 K has been reached, fusion of heli ...
CAPSTONE-poster
... shell. It can no longer support itself by nuclear fusion reactions in its center. The gravity from the material in the outer part of the star takes its inevitable toll on the structure of the star, and forces the inner parts to condense and heat up. The unstable helium burning shell expands and brea ...
... shell. It can no longer support itself by nuclear fusion reactions in its center. The gravity from the material in the outer part of the star takes its inevitable toll on the structure of the star, and forces the inner parts to condense and heat up. The unstable helium burning shell expands and brea ...
Topic 4 - The University of Sheffield
... would have to be single to account for the dark matter. They might be detected because accretion of gas and dust would cause emission lines as the gas atoms collide with each other. (2) Disruption of Binaries - if there are a large number of BHs they would be expected to gravitationally disrupt Wide ...
... would have to be single to account for the dark matter. They might be detected because accretion of gas and dust would cause emission lines as the gas atoms collide with each other. (2) Disruption of Binaries - if there are a large number of BHs they would be expected to gravitationally disrupt Wide ...
Observed properties of SN
... • Release 1 foe as heat by initial explosion (nuclear or neutrino heating after core collapse) • Convert into kinetic energy: v ' 109 cm s-1 [(Esn/1 foe) (M/M¯)-1]1/2 • Cooling by conversion, expansion means lack of thermal energy for radiation • Hence need for radioactive sources ...
... • Release 1 foe as heat by initial explosion (nuclear or neutrino heating after core collapse) • Convert into kinetic energy: v ' 109 cm s-1 [(Esn/1 foe) (M/M¯)-1]1/2 • Cooling by conversion, expansion means lack of thermal energy for radiation • Hence need for radioactive sources ...
Procedurally Generating an Artificial Galaxy
... actually used. Among them, the linear congruential generator is the most common. In the same way that you can choose how many times to run the seeds through the middle-square algorithm, the linear congruential generator can be configured in different ways with different results, some of which are be ...
... actually used. Among them, the linear congruential generator is the most common. In the same way that you can choose how many times to run the seeds through the middle-square algorithm, the linear congruential generator can be configured in different ways with different results, some of which are be ...
Pictures in the Stars, Legends in the Sky
... Today, astronomers say there are 88 constellations. Each constellation is an area in the sky. Each area has boundaries. You may already know some constellations. The Big Dipper (not a constellation) is part of the constellation Ursa Major, or the Big Bear. The two front stars of the dipper point to ...
... Today, astronomers say there are 88 constellations. Each constellation is an area in the sky. Each area has boundaries. You may already know some constellations. The Big Dipper (not a constellation) is part of the constellation Ursa Major, or the Big Bear. The two front stars of the dipper point to ...
On the possibility of a helium white dwarf donor in the presumed
... Abstract. 2S 0918–549 is a low-mass X-ray binary (LMXB) with a low optical to X-ray flux ratio. Probably it is an ultracompact binary with an orbital period shorter than 60 min. Such binaries cannot harbor hydrogen rich donor stars. As with other (sometimes confirmed) ultracompact LMXBs, 2S 0918–549 ...
... Abstract. 2S 0918–549 is a low-mass X-ray binary (LMXB) with a low optical to X-ray flux ratio. Probably it is an ultracompact binary with an orbital period shorter than 60 min. Such binaries cannot harbor hydrogen rich donor stars. As with other (sometimes confirmed) ultracompact LMXBs, 2S 0918–549 ...
Chapter 16, Exercises 51–52, 54
... We are told that the total mass is twice the mass of the Sun. The mass of the Sun is 2 · 1030 kg, so the total mass in this system is 4 · 1030 kg. The period is 10 days, which we need to convert to seconds: 8.64 · 105 seconds. We can therefore find the orbital separation by plugging in the numbers. ...
... We are told that the total mass is twice the mass of the Sun. The mass of the Sun is 2 · 1030 kg, so the total mass in this system is 4 · 1030 kg. The period is 10 days, which we need to convert to seconds: 8.64 · 105 seconds. We can therefore find the orbital separation by plugging in the numbers. ...
Observational properties of stars
... 2. We can use this relation combined with the Eddington relation to derive a relationship between stellar luminosity, , and mass, that has the form L M 3 which is close to the relationship often used for Main Sequence stars! 3. As the star evolves and changes, this will also change the influenc ...
... 2. We can use this relation combined with the Eddington relation to derive a relationship between stellar luminosity, , and mass, that has the form L M 3 which is close to the relationship often used for Main Sequence stars! 3. As the star evolves and changes, this will also change the influenc ...
Astro 3303 - Cornell Astronomy
... Distant galaxies • The galaxy ON-108036 • It has a redshift of 7.2. • That redshift corresponds to a “look back time” of 12.9 Gyr, or an epoch of only 749 Myr after the ...
... Distant galaxies • The galaxy ON-108036 • It has a redshift of 7.2. • That redshift corresponds to a “look back time” of 12.9 Gyr, or an epoch of only 749 Myr after the ...
GRADE 12A: Physics 7
... • The Milky Way is a spiral galaxy, and the Sun lies about two-thirds of the way out from the centre. • The nearest major galaxy to the Milky Way is the Andromeda galaxy (Andromeda nebula), which is also a spiral. • Even the nearest galaxy lies at a distance of a few million light-years. Light reach ...
... • The Milky Way is a spiral galaxy, and the Sun lies about two-thirds of the way out from the centre. • The nearest major galaxy to the Milky Way is the Andromeda galaxy (Andromeda nebula), which is also a spiral. • Even the nearest galaxy lies at a distance of a few million light-years. Light reach ...
Spagna
... including 3 large dark clouds (Cha I, Cha II and Cha III) and several small isolated clouds with 100
... including 3 large dark clouds (Cha I, Cha II and Cha III) and several small isolated clouds with 100
Beyond the iron group: heavy metals in hot subdwarfs
... by Michaud et al. (1985) and Bergeron et al. (1988) have found, however, that diffusion alone cannot account for the large silicon underabundances, and that a competing particle transport mechanism, i.e. a weak stellar wind, must be present. The discovery of strong Ge, Sn and Pb resonance lines can ...
... by Michaud et al. (1985) and Bergeron et al. (1988) have found, however, that diffusion alone cannot account for the large silicon underabundances, and that a competing particle transport mechanism, i.e. a weak stellar wind, must be present. The discovery of strong Ge, Sn and Pb resonance lines can ...
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.