Metallicity maps
... but ram-pressure stripping is very important), they yield different metal distributions and have different time scales ram-pressure in the outskirts of clusters is sufficient to strip gas and form new stars inhomogeneous metallicity distribution, enriched material is not mixed immediately with I ...
... but ram-pressure stripping is very important), they yield different metal distributions and have different time scales ram-pressure in the outskirts of clusters is sufficient to strip gas and form new stars inhomogeneous metallicity distribution, enriched material is not mixed immediately with I ...
gravitational wave Universe - UO Physics
... Fizzlers: Rapidly Rotating Core Collapse Core Collapse in rapidly rotating massive stars may not lead to Type II Supernovas. As core collapses, Ω increases to conserve J. If initial J large enough, centrifugal force halts collapse before ρnuc, nuclear density is reached aborting the supernova. Core ...
... Fizzlers: Rapidly Rotating Core Collapse Core Collapse in rapidly rotating massive stars may not lead to Type II Supernovas. As core collapses, Ω increases to conserve J. If initial J large enough, centrifugal force halts collapse before ρnuc, nuclear density is reached aborting the supernova. Core ...
Jeremy Heyl et al. (PDF document)
... for stellar evolution and gravitational dynamics, and the nearby rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution an ...
... for stellar evolution and gravitational dynamics, and the nearby rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution an ...
The HARPS search for southern extra-solar planets-XI. Super
... This Letter reports on the detection of two super-Earth planets in the Gl 581 system, which is already known to harbour a hot Neptune. One of the planets has a mass of 5 M⊕ and resides at the “warm” edge of the habitable zone of the star. It is thus the known exoplanet that most resembles our own Ea ...
... This Letter reports on the detection of two super-Earth planets in the Gl 581 system, which is already known to harbour a hot Neptune. One of the planets has a mass of 5 M⊕ and resides at the “warm” edge of the habitable zone of the star. It is thus the known exoplanet that most resembles our own Ea ...
Starburst Galaxies Under the Microscope: High
... Since the supernova rate is dominated by stars with a mass of about 8 M (the most numerous stars still producing supernovae), which have a lifetime of about 3 10 7 years, the BrG and [Fe II] emission trace phases of the starbursts that are temporally separated by this amount of time. In principle, ...
... Since the supernova rate is dominated by stars with a mass of about 8 M (the most numerous stars still producing supernovae), which have a lifetime of about 3 10 7 years, the BrG and [Fe II] emission trace phases of the starbursts that are temporally separated by this amount of time. In principle, ...
Abstract - UChicago High Energy Physics
... composition [2, 9, 12–16]. The neutrino flavor composition above the neutrino trapping surface depends not only on thermodynamics in the trapped regions, but also the oscillation of neutrinos as they leave the disk. The high neutrino density coupled with high matter density provide an environment wh ...
... composition [2, 9, 12–16]. The neutrino flavor composition above the neutrino trapping surface depends not only on thermodynamics in the trapped regions, but also the oscillation of neutrinos as they leave the disk. The high neutrino density coupled with high matter density provide an environment wh ...
Maximum Mass Restraint of Neutron Stars
... the core it begins accumulating until it reaches approximately 1.44 solar masses. At this point degeneracy pressures can no longer support the core and the process of star collapse begins. Core collapse is a rather violent process and is caused by the production of gamma rays within the core. Throug ...
... the core it begins accumulating until it reaches approximately 1.44 solar masses. At this point degeneracy pressures can no longer support the core and the process of star collapse begins. Core collapse is a rather violent process and is caused by the production of gamma rays within the core. Throug ...
Astrophysics Lab “A”
... and elaboration of the 2-week astrophysics lab Winds from Hot Stars: Diagnostics and WindMomentum Luminosity Relation (WLR). • before the first lab’s afternoon: Read carefully Sects. 1 – 6 of this manual. The content of Sect. 5 should be understood at least with respect to the basic processes. In ad ...
... and elaboration of the 2-week astrophysics lab Winds from Hot Stars: Diagnostics and WindMomentum Luminosity Relation (WLR). • before the first lab’s afternoon: Read carefully Sects. 1 – 6 of this manual. The content of Sect. 5 should be understood at least with respect to the basic processes. In ad ...
AN ATTEMPT To prove the MOTION OF THE EARTH FROM
... For supposing all the fixt Stars as so many Suns, and each of them to have a Sphere of activity or expansion proportionate to their solidity and activity, and a bigger and brighter bodied Star to have a proportionate bigger space or expansion belonging to it, we should from the knowledge of their Di ...
... For supposing all the fixt Stars as so many Suns, and each of them to have a Sphere of activity or expansion proportionate to their solidity and activity, and a bigger and brighter bodied Star to have a proportionate bigger space or expansion belonging to it, we should from the knowledge of their Di ...
Can TMT Image Habitable Planets ?
... Expected overlap with development team of 2nd generation, more capable ExAO system. Re-use experience/technologies and possibly hardware to reduce schedule/cost/risk of 2nd generation instrument. ...
... Expected overlap with development team of 2nd generation, more capable ExAO system. Re-use experience/technologies and possibly hardware to reduce schedule/cost/risk of 2nd generation instrument. ...
Astrophysics with the Computer: Propagation of Ionization Fronts in
... A hot star is born in an interstellar gas cloud. At first all the gas (hydrogen and helium) is neutral and therefore oprically thick to the ultraviolet (λ < 91 nm) radiation of the star. Where the radiation hits the gas, a layer will be ionised and hence become optically thin. Thus the stellar photo ...
... A hot star is born in an interstellar gas cloud. At first all the gas (hydrogen and helium) is neutral and therefore oprically thick to the ultraviolet (λ < 91 nm) radiation of the star. Where the radiation hits the gas, a layer will be ionised and hence become optically thin. Thus the stellar photo ...
ASTRONOMY 113 Laboratory Lab 5: Spectral Classification of the
... few hundreds of stars ("open clusters") to a few million stars ("globular star clusters"). All of the stars in these clusters are bound to each other by gravity. Star clusters are also valuable laboratories for the study of stars, because within any given cluster all of the stars have the same age, ...
... few hundreds of stars ("open clusters") to a few million stars ("globular star clusters"). All of the stars in these clusters are bound to each other by gravity. Star clusters are also valuable laboratories for the study of stars, because within any given cluster all of the stars have the same age, ...
Magnetic fields generated by r-modes in accreting quark stars
... CV T = Ėaccretion + Ėviscosity − Ėneutrino . ...
... CV T = Ėaccretion + Ėviscosity − Ėneutrino . ...
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.