Molecular Cooling Rates (Neufeld, Lepp and Melnick 1995)
... • How quickly is the outflowing material accelerated? • How does the envelope composition (dust and gas) relate to the photospheric abundances (C-rich or O-rich)? • What roles do photochemistry and shock chemistry play in the circumstellar envelopes of evolved stars? • What is the thermal structure ...
... • How quickly is the outflowing material accelerated? • How does the envelope composition (dust and gas) relate to the photospheric abundances (C-rich or O-rich)? • What roles do photochemistry and shock chemistry play in the circumstellar envelopes of evolved stars? • What is the thermal structure ...
ASTRONOMY 5
... visible light). These appear as “jets” and “lobes” in radio images. Exactly how BHs eject this mixture of gas and magnetic field in narrow jets is not known. 4) The big picture is that big black holes formed at the center of nearly every big galaxy early in its formation as a by-product of galaxy bi ...
... visible light). These appear as “jets” and “lobes” in radio images. Exactly how BHs eject this mixture of gas and magnetic field in narrow jets is not known. 4) The big picture is that big black holes formed at the center of nearly every big galaxy early in its formation as a by-product of galaxy bi ...
The prompt and afterglow emission of GRB991216
... negligible at least in the first phase of the oscillations •The energy and the number of photons increase with time Ruffini, Vitagliano and Xue (2004) Ruffini, Vereshchagin and Xue (2007) ...
... negligible at least in the first phase of the oscillations •The energy and the number of photons increase with time Ruffini, Vitagliano and Xue (2004) Ruffini, Vereshchagin and Xue (2007) ...
The origin of the strongest magnetic fields in dwarfs
... After helium ignition (figure 2) a star shrinks and burns helium relatively quiescently in a convective core. Once the central helium is exhausted too, helium burning moves to a shell which rapidly catches up with the hydrogen burning shell. The star expands again to become an asymptotic giant. If t ...
... After helium ignition (figure 2) a star shrinks and burns helium relatively quiescently in a convective core. Once the central helium is exhausted too, helium burning moves to a shell which rapidly catches up with the hydrogen burning shell. The star expands again to become an asymptotic giant. If t ...
Stellarium01 Starter Part A B Doc - ASTR101
... What constellation is at the Zenith at “Current Time” tonight? ___________________ How many constellations are in the sky at “Current Time” tonight? (count them!) _________ Open the Search window (CTRL-F or F3, or FN-F3 in some) to help you find the following ...
... What constellation is at the Zenith at “Current Time” tonight? ___________________ How many constellations are in the sky at “Current Time” tonight? (count them!) _________ Open the Search window (CTRL-F or F3, or FN-F3 in some) to help you find the following ...
Extrasolar Cosmochemistry
... What are the elemental compositions of extrasolar planets and planetesimals? Are they familiar or exotic? Which, if any, extrasolar planetesimals experience differentiation? Externally polluted white dwarfs provide an opportunity to address these questions. After undergoing extensive evolution, star ...
... What are the elemental compositions of extrasolar planets and planetesimals? Are they familiar or exotic? Which, if any, extrasolar planetesimals experience differentiation? Externally polluted white dwarfs provide an opportunity to address these questions. After undergoing extensive evolution, star ...
Supermassive Black Holes in Inactive Galaxies Encyclopedia of Astronomy & Astrophysics eaa.iop.org
... 600±37 km s–1. This is the highest dispersion measured in any galactic center. The velocity of escape from the nucleus would be much smaller, Vesc ≃ 352 km s–1, if it consisted only of stars. Without extra mass to bind it, the cluster would fling itself apart in ~ 2 × 104 yr. Independent of any velo ...
... 600±37 km s–1. This is the highest dispersion measured in any galactic center. The velocity of escape from the nucleus would be much smaller, Vesc ≃ 352 km s–1, if it consisted only of stars. Without extra mass to bind it, the cluster would fling itself apart in ~ 2 × 104 yr. Independent of any velo ...
Microsoft Word 97
... d) The spectrum of an emission nebula therefore consists of emission lines. e) Emission nebula often look red because the red light of hydrogen is strongest in them. Other types of emission nebulae can photograph as green, because of green light from oxygen ions; other colors are possible as well. f ...
... d) The spectrum of an emission nebula therefore consists of emission lines. e) Emission nebula often look red because the red light of hydrogen is strongest in them. Other types of emission nebulae can photograph as green, because of green light from oxygen ions; other colors are possible as well. f ...
Cosmology with objects from the Hamburg Quasar Surveys
... The direct measurement of the SED is possible only in absorption line systems where a sufficient number of ionization stages can be observed simultaneously. And even in such a favourable case it is always possible that a neighbouring galaxy or AGN is dominant. Therefore in practice the SED and inten ...
... The direct measurement of the SED is possible only in absorption line systems where a sufficient number of ionization stages can be observed simultaneously. And even in such a favourable case it is always possible that a neighbouring galaxy or AGN is dominant. Therefore in practice the SED and inten ...
Dynamical Mass Measurements of Pre-Main
... radial velocities of the primary stars relative to their secondaries (e.g., Rucinski, 1999). These effects can be minimized by selecting templates that are well matched to the target stars in spectral type, by avoiding orbital phases subject to strong line blending, and by employing techniques desig ...
... radial velocities of the primary stars relative to their secondaries (e.g., Rucinski, 1999). These effects can be minimized by selecting templates that are well matched to the target stars in spectral type, by avoiding orbital phases subject to strong line blending, and by employing techniques desig ...
Tasks - ESA Science
... Astronomy is an accessible and visual science, making it ideal for educational purposes. Over the last few years the NASA/ESA Hubble Space Telescope and the ESO telescopes at the La Silla and Paranal Observatories in Chile have presented ever deeper and more spectacular views of the Universe. Howeve ...
... Astronomy is an accessible and visual science, making it ideal for educational purposes. Over the last few years the NASA/ESA Hubble Space Telescope and the ESO telescopes at the La Silla and Paranal Observatories in Chile have presented ever deeper and more spectacular views of the Universe. Howeve ...
Kein Folientitel - tls
... Two stars are in long period orbits around each other. A planet is in a shorter period orbit around one star. If the orbit of the planet is inclined, the outer planet can „pump up“ the eccentricity of the planet. Planets can go from circular to eccentric orbits. This was first investigated by Kozai ...
... Two stars are in long period orbits around each other. A planet is in a shorter period orbit around one star. If the orbit of the planet is inclined, the outer planet can „pump up“ the eccentricity of the planet. Planets can go from circular to eccentric orbits. This was first investigated by Kozai ...
Neutron Stars
... of general relativity. This work demonstrated, among other interesting ideas, that neutron stars could not be of arbitrarily large mass: general relativity introduces the concept of a neutron star maximum mass. Interestingly, the magnitude of the neutron star maximum mass is of the same order as the ...
... of general relativity. This work demonstrated, among other interesting ideas, that neutron stars could not be of arbitrarily large mass: general relativity introduces the concept of a neutron star maximum mass. Interestingly, the magnitude of the neutron star maximum mass is of the same order as the ...
Star Formation and Feedback II: The IMF and the SFR
... integrated properties for the SMC. Integrating our extinctioncorrected Hα map, we obtain a global star formation rate SFRSMC ∼ 0.037 M" yr−1 . The extinction correction accounts for ∼10% of the global SFR. About 30% of the integrated Hα emission arises from extended low surface brightness regions, w ...
... integrated properties for the SMC. Integrating our extinctioncorrected Hα map, we obtain a global star formation rate SFRSMC ∼ 0.037 M" yr−1 . The extinction correction accounts for ∼10% of the global SFR. About 30% of the integrated Hα emission arises from extended low surface brightness regions, w ...
Dr.Sinha - Indico
... star with the realisation that changes in the internal structure as the star spins down, will be reflected in the moment of inertia and hence the deceleration. In this letter we are not considering the “recycling” scenario of binary system. During the spin down of a (say) millisecond neutron star, t ...
... star with the realisation that changes in the internal structure as the star spins down, will be reflected in the moment of inertia and hence the deceleration. In this letter we are not considering the “recycling” scenario of binary system. During the spin down of a (say) millisecond neutron star, t ...
Physics in the Balance - Max-Planck
... short range. In very large nuclei, the weaker but longer-range electromagnetic force thus gains the upper hand and causes them to decay. This can be prevented by a stabilizing effect from quantum mechanics. It also plays an important role in the shell of electrons around the atoms. Electrons, proton ...
... short range. In very large nuclei, the weaker but longer-range electromagnetic force thus gains the upper hand and causes them to decay. This can be prevented by a stabilizing effect from quantum mechanics. It also plays an important role in the shell of electrons around the atoms. Electrons, proton ...
![arXiv:1007.5481v1 [astro-ph.EP] 30 Jul 2010](http://s1.studyres.com/store/data/016640559_1-8bc20118c4d48efd5cfe1f2b10a85bec-300x300.png)
Spiral shock triggering of star formation
... •Local dissipation of turbulence •Star formation • SF involves ~10% of mass ...
... •Local dissipation of turbulence •Star formation • SF involves ~10% of mass ...
Star counts in the Galaxy-Simulating from very deep to very shallow
... interpolated in between. This separation was interpreted as a coarse separation into “young” and “old” populations. Red giants instead were assigned 250 pc. Gilmore & Reid (1983) adopt similar approximations for main sequence stars. Méndez & van Altena (1996, 1998) do the same, and moreover assume a ...
... interpolated in between. This separation was interpreted as a coarse separation into “young” and “old” populations. Red giants instead were assigned 250 pc. Gilmore & Reid (1983) adopt similar approximations for main sequence stars. Méndez & van Altena (1996, 1998) do the same, and moreover assume a ...
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.