Parity violating measurements of neutron densities
... • NS cool by nu emission from interior. Additional hadrons allow further beta decay and faster cooling. • Beta decay of neutrons (direct URCA process) will be Pauli blocked unless proton fraction Yp is large. • A large sym E makes NS core more symmetric and increases Yp. • If Rn(208Pb) is large, dir ...
... • NS cool by nu emission from interior. Additional hadrons allow further beta decay and faster cooling. • Beta decay of neutrons (direct URCA process) will be Pauli blocked unless proton fraction Yp is large. • A large sym E makes NS core more symmetric and increases Yp. • If Rn(208Pb) is large, dir ...
The evolution of Red Supergiants to supernova in the LMC cluster
... from 2MASS, Spitzer and WISE (Skrutskie et al. 2006; Werner et al. 2004; Wright et al. 2010) and is listed in Table 2. A finding chart for NGC2100 is shown in Fig. 1 in which the RSGs are numbered based on [5.6]-band magnitude. Star #13 has been omitted from our analysis due to large disagreements b ...
... from 2MASS, Spitzer and WISE (Skrutskie et al. 2006; Werner et al. 2004; Wright et al. 2010) and is listed in Table 2. A finding chart for NGC2100 is shown in Fig. 1 in which the RSGs are numbered based on [5.6]-band magnitude. Star #13 has been omitted from our analysis due to large disagreements b ...
Circum-stellar medium around rotating massive stars at solar
... conditions for entire stellar systems. For the present study, it allows us to accommodate in an easy and transparent way the timedependent boundary conditions of our single star. Although not used in the present study, the implementation can equally handle boundary conditions for entire stellar syst ...
... conditions for entire stellar systems. For the present study, it allows us to accommodate in an easy and transparent way the timedependent boundary conditions of our single star. Although not used in the present study, the implementation can equally handle boundary conditions for entire stellar syst ...
55 Ignacio Negueruela and Amparo Marco
... stars (≈20), we determined an initial PSF by fitting the best function between the five options offered by the PSF routine inside DAOPHOT. We allowed the PSF to be variable (in order two) across the frame to take into account the systematic pattern of PSF variability with position on the chip. We ne ...
... stars (≈20), we determined an initial PSF by fitting the best function between the five options offered by the PSF routine inside DAOPHOT. We allowed the PSF to be variable (in order two) across the frame to take into account the systematic pattern of PSF variability with position on the chip. We ne ...
Gamow-Teller response in deformed even and odd neutron
... axially symmetric prolate and oblate, as well as triaxial shapes at close energies. These features are supported by spectroscopic observations [10] including 2+ lifetime measurements [11–13] and quadrupole moments for rotational bands [13], as well as by laser spectroscopy measurements on Zr [14] an ...
... axially symmetric prolate and oblate, as well as triaxial shapes at close energies. These features are supported by spectroscopic observations [10] including 2+ lifetime measurements [11–13] and quadrupole moments for rotational bands [13], as well as by laser spectroscopy measurements on Zr [14] an ...
Theoretical and observational framework Spectroscopic approach
... • The presence of fast HB rotators is confirmed and extended to other clusters. • The abundance of fast HB rotators can apparently change from cluster to cluster. • The change in rotational velocity seems to be associated to the onset of diffusive processes in the stellar atmosphere. • Radiative lev ...
... • The presence of fast HB rotators is confirmed and extended to other clusters. • The abundance of fast HB rotators can apparently change from cluster to cluster. • The change in rotational velocity seems to be associated to the onset of diffusive processes in the stellar atmosphere. • Radiative lev ...
Chapter 9 Early stages of evolution and the main sequence phase
... The process of star formation constitutes one of the main problems of modern astrophysics. Compared to our understanding of what happens after stars have formed out of the interstellar medium – that is, stellar evolution – star formation is a very ill-understood problem. No predictive theory of star ...
... The process of star formation constitutes one of the main problems of modern astrophysics. Compared to our understanding of what happens after stars have formed out of the interstellar medium – that is, stellar evolution – star formation is a very ill-understood problem. No predictive theory of star ...
Much of our original knowledge of interstellar dust comes from a
... For a large object like an asteroid we would have Qem~1. However, for a dust particle in the infrared Qem=Qabs<<1 in general because the particle is much smaller than the wavelength. In the visible Qabs~1. All this means that small particles will be hotter than larger ones because they do not ...
... For a large object like an asteroid we would have Qem~1. However, for a dust particle in the infrared Qem=Qabs<<1 in general because the particle is much smaller than the wavelength. In the visible Qabs~1. All this means that small particles will be hotter than larger ones because they do not ...
1. INTRODUCTION 2. MASS AND LIGHT
... Although to date no stars have been detected in the Magellanic Stream, it could in principle have a stellar component which would likewise be extended. The debris could also be from an unrelated galaxy which, like the Sagittarius dwarf (D5¡ ] 20¡), might be substantially extended along its orbit. Su ...
... Although to date no stars have been detected in the Magellanic Stream, it could in principle have a stellar component which would likewise be extended. The debris could also be from an unrelated galaxy which, like the Sagittarius dwarf (D5¡ ] 20¡), might be substantially extended along its orbit. Su ...
Study of an unbiased sample of B stars observed with Hipparcos
... we know the cause of the pulsations. The Hipparcos sample of B-type variable stars offers the possibility to do this. A caveat to place the supergiants in the HR diagram is that their temperature and luminosity are difficult to determine, especially by means of photometric data alone. Nevertheless, ...
... we know the cause of the pulsations. The Hipparcos sample of B-type variable stars offers the possibility to do this. A caveat to place the supergiants in the HR diagram is that their temperature and luminosity are difficult to determine, especially by means of photometric data alone. Nevertheless, ...
The Milky Way and Andromeda galaxies in a constrained
... whether our simulation predicts the formation of two large spiral galaxies similar to the MW and M 31 and what are the mechanisms determining/affecting their formation. We will show that only the simulated MW has a stable stellar disc that survives to z = 0; while in M 31 various mergers continuously ...
... whether our simulation predicts the formation of two large spiral galaxies similar to the MW and M 31 and what are the mechanisms determining/affecting their formation. We will show that only the simulated MW has a stable stellar disc that survives to z = 0; while in M 31 various mergers continuously ...
THE DEARTH OF UV-BRIGHT STARS IN M32
... theoretical predictions. In contrast, the rapid evolution of these stars means few of them are found in Galactic globular clusters (the traditional testing ground for stellar evolution), while distance and reddening uncertainties hamper their study in the Galactic field population. In an elliptical ...
... theoretical predictions. In contrast, the rapid evolution of these stars means few of them are found in Galactic globular clusters (the traditional testing ground for stellar evolution), while distance and reddening uncertainties hamper their study in the Galactic field population. In an elliptical ...
Here - NASA/IPAC Extragalactic Database
... birth of massive stars (i.e. a few Myr ago). The status of the chemical composition of PN envelopes is more complex. Some constituents have not been changed and reflect the state of the gas out of which the progenitor of the PN was formed, 10 8 yr ago or more. Other elements, such as carbon and nitr ...
... birth of massive stars (i.e. a few Myr ago). The status of the chemical composition of PN envelopes is more complex. Some constituents have not been changed and reflect the state of the gas out of which the progenitor of the PN was formed, 10 8 yr ago or more. Other elements, such as carbon and nitr ...
Number Theory and the Periodicity of Matter
... The point of convergence is established by plotting a modular(4) set of rational fractions, ordered in Farey sequence. This infinite set contains a modular subset of points that represent stable nuclides of allowed nuclear composition along a set of 11 regularly spaced festoons. A second Farey sequen ...
... The point of convergence is established by plotting a modular(4) set of rational fractions, ordered in Farey sequence. This infinite set contains a modular subset of points that represent stable nuclides of allowed nuclear composition along a set of 11 regularly spaced festoons. A second Farey sequen ...
High-resolution Gamma-ray Spectroscopy at SPIRAL2
... science case into several major topics which are outlined below. Further details can be found in the corresponding sections following the general part. Proton drip-line studies and N=Z nuclei Neutron-deficient nuclei at or sometimes even beyond the proton drip line were studied extensively in the pa ...
... science case into several major topics which are outlined below. Further details can be found in the corresponding sections following the general part. Proton drip-line studies and N=Z nuclei Neutron-deficient nuclei at or sometimes even beyond the proton drip line were studied extensively in the pa ...
Stars Stellar Lifetimes Life cycles of low
... gravity of their enormous mass and the pressure produced by the energy of fusion reactions. A main sequence star is in equilibrium as Hydrogen burning supports it against gravitational collapse. What happens as the hydrogen runs out? © 2007 Pearson Education Inc., publishing as Pearson Addison-Wesle ...
... gravity of their enormous mass and the pressure produced by the energy of fusion reactions. A main sequence star is in equilibrium as Hydrogen burning supports it against gravitational collapse. What happens as the hydrogen runs out? © 2007 Pearson Education Inc., publishing as Pearson Addison-Wesle ...
Globular and Open Clusters in our Galaxy
... generations of stars formed in our Galaxy. Therefore all globular clusters must be very old. Since all the stars in a cluster are essentially at the same distance, their relative apparent magnitudes also correspond to their relative physical luminosities. Figure 4 depicts the color-magnitude diagram ...
... generations of stars formed in our Galaxy. Therefore all globular clusters must be very old. Since all the stars in a cluster are essentially at the same distance, their relative apparent magnitudes also correspond to their relative physical luminosities. Figure 4 depicts the color-magnitude diagram ...
Europium, Samarium, and Neodymium Isotopic Fractions in Metal
... 4, respectively. We summarize the available atomic data for each species in § 3. Our measurements of the elemental abundances and isotopic fractions are presented in § 5 and § 6. In § 7 we discuss the implications of our measurements in the context of using isotopic fractions of multiple species to ...
... 4, respectively. We summarize the available atomic data for each species in § 3. Our measurements of the elemental abundances and isotopic fractions are presented in § 5 and § 6. In § 7 we discuss the implications of our measurements in the context of using isotopic fractions of multiple species to ...
THE ORIGIN AND EVOLUTION OF PLANETARY NEBULAE
... high temperatures to low temperatures, PN were thought to be very young stars because of their high temperatures. From his studies of the velocity distribution of PN, Curtis (1918) found that PN are more similar to late-type stars and are unlikely to be young objects. Theoretical understanding of th ...
... high temperatures to low temperatures, PN were thought to be very young stars because of their high temperatures. From his studies of the velocity distribution of PN, Curtis (1918) found that PN are more similar to late-type stars and are unlikely to be young objects. Theoretical understanding of th ...
eng pdf 274 kb
... perfect angular measurements play the determinative role in the estimation of the excitation energy scale while their momentum per nucleon may be taken the same as for an incoming nucleus, • reliable determination of charges of relativistic fragments in provided over a wide range, • nuclear clusteri ...
... perfect angular measurements play the determinative role in the estimation of the excitation energy scale while their momentum per nucleon may be taken the same as for an incoming nucleus, • reliable determination of charges of relativistic fragments in provided over a wide range, • nuclear clusteri ...
Summary of IAU GA SpS5-I. Obscured and distant clusters
... different environments, an essential tool for testing theoretical models. Massive clusters are especially important in this context, as they allow us to beat the small-number statistics that plague typical intermediate-mass cluster studies. With a massive stellar cluster † Defined as being a few Myr ...
... different environments, an essential tool for testing theoretical models. Massive clusters are especially important in this context, as they allow us to beat the small-number statistics that plague typical intermediate-mass cluster studies. With a massive stellar cluster † Defined as being a few Myr ...
ISOLATED, MASSIVE SUPERGIANTS NEAR THE GALACTIC
... C iii, N ii, and /or Mg ii (see Morris et al. 1996; Figer et al. 1999). We measured the equivalent widths of the lines by modeling the continuum between 2.1 and 2.4 m as a second-order polynomial and the lines as Gaussians. The equivalent widths also are listed in Table 2. The presence of strong H ...
... C iii, N ii, and /or Mg ii (see Morris et al. 1996; Figer et al. 1999). We measured the equivalent widths of the lines by modeling the continuum between 2.1 and 2.4 m as a second-order polynomial and the lines as Gaussians. The equivalent widths also are listed in Table 2. The presence of strong H ...
Chapter 9 Red Giant Evolution
... Depending on mass, these steps can lead to the three qualitative scenarios that are sketched in the above figure. • Lowest mass main-sequence stars (M <∼ 0.5M⊙): core temperatures never rise high enough to ignite the helium produced by proton burning and the star evolves to a helium white dwarf. • I ...
... Depending on mass, these steps can lead to the three qualitative scenarios that are sketched in the above figure. • Lowest mass main-sequence stars (M <∼ 0.5M⊙): core temperatures never rise high enough to ignite the helium produced by proton burning and the star evolves to a helium white dwarf. • I ...
The Formation of Primordial Luminous Objects - SLAC
... the first structure which formed in the early Universe were Earth-mass dark-matter haloes (but see also Zhao et al. 2005 for criticism about this result); (ii) Growth rate changes: in general, perturbations grow because of gravity; however, the details of the process change with time, leaving an imp ...
... the first structure which formed in the early Universe were Earth-mass dark-matter haloes (but see also Zhao et al. 2005 for criticism about this result); (ii) Growth rate changes: in general, perturbations grow because of gravity; however, the details of the process change with time, leaving an imp ...
FLARESTARSINTHEORIONN EBULAREGION SUMARIO Durante
... typical T Tauri stars in which, during long periods, the strong emission lines of H, CaII and some other bright lines, plus a rather strong ultraviolet continuum, are observed; b) nebular irregular variables with possible fainter emission lines and without conspicuous ultraviolet excesses during the ...
... typical T Tauri stars in which, during long periods, the strong emission lines of H, CaII and some other bright lines, plus a rather strong ultraviolet continuum, are observed; b) nebular irregular variables with possible fainter emission lines and without conspicuous ultraviolet excesses during the ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.