ppt - A century of cosmology
... candidate faint Ly emitters at z~8-10 with SFR <1 M yr-1 - a population which may contribute significantly to reionization. • Exhaustive spectroscopic and imaging follow-up supports hypothesis that many of lensed Lya emitters are at z~10 but additional follow-up still required. Final confirmation ...
... candidate faint Ly emitters at z~8-10 with SFR <1 M yr-1 - a population which may contribute significantly to reionization. • Exhaustive spectroscopic and imaging follow-up supports hypothesis that many of lensed Lya emitters are at z~10 but additional follow-up still required. Final confirmation ...
Search for giant planets in M67 III: excess of Hot Jupiters in dense
... Hot Jupiters (HJs) are defined as giant planets (M p > 0.3MJup ) in short period orbits (P < 10 days). They show an occurance rate of ∼1.2% around Sun-like field stars (Wright et al. 2012; Mayor et al. 2011). These close-in giant planets are highly unlikely to have formed in situ and it is believed ...
... Hot Jupiters (HJs) are defined as giant planets (M p > 0.3MJup ) in short period orbits (P < 10 days). They show an occurance rate of ∼1.2% around Sun-like field stars (Wright et al. 2012; Mayor et al. 2011). These close-in giant planets are highly unlikely to have formed in situ and it is believed ...
Metal-poor Stars
... [Fe/H] < −4.0 are extremely C-rich. The fraction of C-rich stars may also increase with increasing distance from the Galactic plane (Frebel et al. 2006b). Many C-rich stars also show an enhancement in neutron-capture elements. These elements are produced in the interiors of intermediate-mass asympto ...
... [Fe/H] < −4.0 are extremely C-rich. The fraction of C-rich stars may also increase with increasing distance from the Galactic plane (Frebel et al. 2006b). Many C-rich stars also show an enhancement in neutron-capture elements. These elements are produced in the interiors of intermediate-mass asympto ...
INTERSTELLAR MedLab
... Dark – high densities of dust and gas that redden or extinct the light from the stars located behind the cloud. These are also where molecules are likely to be found. During the course of this laboratory exercise, you will study the interstellar medium – where stars are formed and into which the ste ...
... Dark – high densities of dust and gas that redden or extinct the light from the stars located behind the cloud. These are also where molecules are likely to be found. During the course of this laboratory exercise, you will study the interstellar medium – where stars are formed and into which the ste ...
The following slide show is a compilation of slides from... have been produced by different members of the fusion and...
... The following slide show is a compilation of slides from many previous similar slide shows that have been produced by different members of the fusion and plasma physics education community. We realize that some of the information contained herein must be updated. Please send comments, complaints, an ...
... The following slide show is a compilation of slides from many previous similar slide shows that have been produced by different members of the fusion and plasma physics education community. We realize that some of the information contained herein must be updated. Please send comments, complaints, an ...
CPW Science Passage
... CPW Science Passage 9th Grade An astronomy class is given the following facts about stellar evolution. 1. A star’s evolution can be divided in two 3 stages: pre-main sequence (pre-MS), main sequence (MS), and post-main sequence (post-MS). 2. Gravity causes part of a cloud of gas and dust to collapse ...
... CPW Science Passage 9th Grade An astronomy class is given the following facts about stellar evolution. 1. A star’s evolution can be divided in two 3 stages: pre-main sequence (pre-MS), main sequence (MS), and post-main sequence (post-MS). 2. Gravity causes part of a cloud of gas and dust to collapse ...
Formation of millisecond pulsars with CO white dwarf companions–I
... 2 M A S S T R A N S F E R I N X - R AY B I N A R I E S Consider a close interacting binary system which consists of a nondegenerate donor star and a compact object, in our case a neutron star. If the orbital separation is small enough, the (evolved) nondegenerate star fills its inner common equipote ...
... 2 M A S S T R A N S F E R I N X - R AY B I N A R I E S Consider a close interacting binary system which consists of a nondegenerate donor star and a compact object, in our case a neutron star. If the orbital separation is small enough, the (evolved) nondegenerate star fills its inner common equipote ...
Astronomy 112: The Physics of Stars Class 8 Notes: Nuclear
... The transition from hydrogen to helium-4 takes us to the first big peak in the binding energy per nucleon curve, and moves us from a reaction where the Coulomb barrier to the first step is 1 (Zi = Zj = 1) to one where it is 4 (Zi = Zj = 2). In fact, we’ll see in a moment that it is even worse than t ...
... The transition from hydrogen to helium-4 takes us to the first big peak in the binding energy per nucleon curve, and moves us from a reaction where the Coulomb barrier to the first step is 1 (Zi = Zj = 1) to one where it is 4 (Zi = Zj = 2). In fact, we’ll see in a moment that it is even worse than t ...
Gilmore - Astrometry and Astrophysics in the Gaia sky
... rare stellar types and rapid evolutionary phases in large numbers parallax calibration of all distance indicators e.g. Cepheids and RR Lyrae to LMC/SMC ...
... rare stellar types and rapid evolutionary phases in large numbers parallax calibration of all distance indicators e.g. Cepheids and RR Lyrae to LMC/SMC ...
Characteristics of Our Galaxy
... variables (useful for judging distances), pre-main sequence stars, T-Tauri stars, Herbigharo objects, and even some A stars can be found in the arms. These stars are very metal rich and have highly circular orbits, although they comprise likely less than one percent of Milky Way stars. Young thin d ...
... variables (useful for judging distances), pre-main sequence stars, T-Tauri stars, Herbigharo objects, and even some A stars can be found in the arms. These stars are very metal rich and have highly circular orbits, although they comprise likely less than one percent of Milky Way stars. Young thin d ...
The AcroCoRoT objectives (10 min) - IAG-Usp
... AcRoCorot objectives : be ready when data come to use them efficiently hence organisation of meetings such as the present one to motivate - teams with similar interest to continue to meet and talk (collaboration, exchange of brain thinkings and tools) ...
... AcRoCorot objectives : be ready when data come to use them efficiently hence organisation of meetings such as the present one to motivate - teams with similar interest to continue to meet and talk (collaboration, exchange of brain thinkings and tools) ...
Document
... We used to think massive cluster formation to be a thing of the past (the Globular Clusters). First, we began to see evidence of very massive clusters (proto-globular clusters) forming in other galaxies ...
... We used to think massive cluster formation to be a thing of the past (the Globular Clusters). First, we began to see evidence of very massive clusters (proto-globular clusters) forming in other galaxies ...
How astero-seismology can help to infer properties of - IAG-Usp
... circulation, differential rotation and turbulence: J(t) caused by surface losses by stellar winds (B, thermal) or surface gain by interaction with surrounding : J(t) These processes cause chemical transport which in turn affects the structure and evolution of the star ...
... circulation, differential rotation and turbulence: J(t) caused by surface losses by stellar winds (B, thermal) or surface gain by interaction with surrounding : J(t) These processes cause chemical transport which in turn affects the structure and evolution of the star ...
Two distinct sequences of blue straggler stars in the globular cluster
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
Document
... The strong lines in the Chandra spectrum of z Puppis can be fit by reasonable combinations of wind parameters. These fits indicate that the X-ray emitting plasma surrounding this star is embedded in the accelerating and absorbing wind. ...
... The strong lines in the Chandra spectrum of z Puppis can be fit by reasonable combinations of wind parameters. These fits indicate that the X-ray emitting plasma surrounding this star is embedded in the accelerating and absorbing wind. ...
Models for GRBs and diverse transients
... the other pole), is not especially small, just its power. A jet of any power will eventually break out, provided it is artificially maintained long enough, but unless it does there is no GRB. At both 37 and 81 s in figure 3, there is no material with G greater than approximately 2 except what is insid ...
... the other pole), is not especially small, just its power. A jet of any power will eventually break out, provided it is artificially maintained long enough, but unless it does there is no GRB. At both 37 and 81 s in figure 3, there is no material with G greater than approximately 2 except what is insid ...
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.