Sources with
... From 0.01 M brown dwarfs powered only by gravitational energy To >100 M stars with lifetimes around 1million years ...
... From 0.01 M brown dwarfs powered only by gravitational energy To >100 M stars with lifetimes around 1million years ...
CoRoT Observations of O Stars: Diverse Origins of Variability
... include some type of granulation, or the onset of clumping in the wind. 2.4. HD 47129 (O7.5 I + O6 I) This is the well-known binary Plaskett’s star. Mahy et al. (2011) found the orbital period (P = 14.39625 d) in the observed light curve. They also found another significant ...
... include some type of granulation, or the onset of clumping in the wind. 2.4. HD 47129 (O7.5 I + O6 I) This is the well-known binary Plaskett’s star. Mahy et al. (2011) found the orbital period (P = 14.39625 d) in the observed light curve. They also found another significant ...
Subatomic particle processes within neutron stars
... stars provide a high-pressure environment in which numerous new particle processes are likely to compete with each other. These processes range from the almost traditional (but certainly far from old-fashioned) generation of hyperons or formation of kaon condensates and H-matter to the newly non-con ...
... stars provide a high-pressure environment in which numerous new particle processes are likely to compete with each other. These processes range from the almost traditional (but certainly far from old-fashioned) generation of hyperons or formation of kaon condensates and H-matter to the newly non-con ...
Hubble Does Double-Duty Science: Finding Planets and
... Out of 229,701 stars that could be searched, 105 showed flares (128 flares total; some stars flared multiple times). The flare energies and peak intensities are consistent with those seen in nearby active stars (1033-1035 ergs), and show a disconnect with solar flare behavior. Based on the star’s br ...
... Out of 229,701 stars that could be searched, 105 showed flares (128 flares total; some stars flared multiple times). The flare energies and peak intensities are consistent with those seen in nearby active stars (1033-1035 ergs), and show a disconnect with solar flare behavior. Based on the star’s br ...
Dust Formation in a Galaxy with Primitive Abundances REPORTS
... [Z/H] = −1.33 T 0.20 for the Sculptor Dwarf (26) and [Z/H] = 0.93 T 0.30 for Fornax [based on [Fe/H] = −1.0 T 0.3 (36) and assuming the same [a/Fe] as for the Sculptor Dwarf]. The weak trend of increasing acetylene absorption with decreasing metallicity is more readily apparent when the data are exa ...
... [Z/H] = −1.33 T 0.20 for the Sculptor Dwarf (26) and [Z/H] = 0.93 T 0.30 for Fornax [based on [Fe/H] = −1.0 T 0.3 (36) and assuming the same [a/Fe] as for the Sculptor Dwarf]. The weak trend of increasing acetylene absorption with decreasing metallicity is more readily apparent when the data are exa ...
Unit 2 PowerPoint Unit2_BigHistoryProject2013_PPT-7
... • Over time, human observations of the planets and stars became more precise and led some scientists to suggest alternative theories. • Copernicus, Kepler, and Galileo contributed to a new view which put the Sun at the center of the Universe, with the Earth moving around it in an elliptical (rather ...
... • Over time, human observations of the planets and stars became more precise and led some scientists to suggest alternative theories. • Copernicus, Kepler, and Galileo contributed to a new view which put the Sun at the center of the Universe, with the Earth moving around it in an elliptical (rather ...
Future Supernova Projects
... • small dispersion • single objects (simpler than galaxies) • can be observed over wide z range Challenges: • dust (grey dust) • chemical composition • evolution • photometric calibration (e.g., Vega) • environmental differences Systematics • lensing Step 2 ...
... • small dispersion • single objects (simpler than galaxies) • can be observed over wide z range Challenges: • dust (grey dust) • chemical composition • evolution • photometric calibration (e.g., Vega) • environmental differences Systematics • lensing Step 2 ...
the Big Bang
... Note: far from being an exotic faraway phenomenon, realize that the CMB nowadays is counting for approximately 1% of the noise on your (camping) tv set … !!!! Live broadcast from the Big Bang !!!! Courtesy: W. Hu ...
... Note: far from being an exotic faraway phenomenon, realize that the CMB nowadays is counting for approximately 1% of the noise on your (camping) tv set … !!!! Live broadcast from the Big Bang !!!! Courtesy: W. Hu ...
UvA-DARE (Digital Academic Repository)
... withh B12 the magnetic field strength in units of 10 12 Gauss and P in units of 1 0 - 1 5 s/s. Ass pulsars grow older, their rotation slows down and their fields may decrease in strength. Eventuallyy the polar cap voltage falls below a certain value, the pulsar switches off: it 'dies'. A nn often us ...
... withh B12 the magnetic field strength in units of 10 12 Gauss and P in units of 1 0 - 1 5 s/s. Ass pulsars grow older, their rotation slows down and their fields may decrease in strength. Eventuallyy the polar cap voltage falls below a certain value, the pulsar switches off: it 'dies'. A nn often us ...
University of Groningen Colliding winds in Wolf-Rayet
... where the lower mass stars (< 40 M ) undergo the red supergiant (RSG) phase and the higher ones (> 40 M ) undergo the luminous blue variable (LBV) phase. The Wolf-Rayet phase lasts for about 5 105 years, and the resulting supernovae are of Type Ib and Ic. Since the first detection by Wolf and Ra ...
... where the lower mass stars (< 40 M ) undergo the red supergiant (RSG) phase and the higher ones (> 40 M ) undergo the luminous blue variable (LBV) phase. The Wolf-Rayet phase lasts for about 5 105 years, and the resulting supernovae are of Type Ib and Ic. Since the first detection by Wolf and Ra ...
Coronal Mass Ejections and Angular Momentum Loss in Young Stars
... disks? In Aarnio et al. (2010), we did not find evidence for this. Second, if there is not a star-disk link, how do the loops remain stable for the multiple rotation periods over which the X-ray flares are observed to decay? We showed in Aarnio et al. (2012) that when modeled as hot prominences, the ...
... disks? In Aarnio et al. (2010), we did not find evidence for this. Second, if there is not a star-disk link, how do the loops remain stable for the multiple rotation periods over which the X-ray flares are observed to decay? We showed in Aarnio et al. (2012) that when modeled as hot prominences, the ...
Variables, Star Clusters, and Nebulae (Professor Powerpoint)
... universe was young. Open clusters formed more recently, out of ``recycled'' material containing heavy ...
... universe was young. Open clusters formed more recently, out of ``recycled'' material containing heavy ...
Behaviour of elements from lithium to europium in stars with and
... We conducted an analysis of the distribution of elements from lithium to europium in 200 dwarfs in the solar neighbourhood (∼20 pc) with temperatures in the range 4800–6200 K and metallicities [Fe/H] higher than –0.5 dex. Determinations of atmospheric parameters and the chemical compositions of the ...
... We conducted an analysis of the distribution of elements from lithium to europium in 200 dwarfs in the solar neighbourhood (∼20 pc) with temperatures in the range 4800–6200 K and metallicities [Fe/H] higher than –0.5 dex. Determinations of atmospheric parameters and the chemical compositions of the ...
Lecture5
... (iii) Spectroscopic Binaries (FK Sec. 5-9, 17-10, Lecture notes) We can identify the binary motion, characteristics of the component stars, etc., by measuring periodic shifting of spectral lines due to the Doppler effect as the stars move around the COM. In most cases the component two stars cannot ...
... (iii) Spectroscopic Binaries (FK Sec. 5-9, 17-10, Lecture notes) We can identify the binary motion, characteristics of the component stars, etc., by measuring periodic shifting of spectral lines due to the Doppler effect as the stars move around the COM. In most cases the component two stars cannot ...
Slide 1
... Like the Miras , the Semiregulars are red giant or supergiant pulsating stars, but oscillating with less regularity as indicated by their name. They are divided in different classes: SRa, SRb, SRc, SRd (super giants), from the most to the less regular shape of their light curve. The study of the per ...
... Like the Miras , the Semiregulars are red giant or supergiant pulsating stars, but oscillating with less regularity as indicated by their name. They are divided in different classes: SRa, SRb, SRc, SRd (super giants), from the most to the less regular shape of their light curve. The study of the per ...
SUPERNOVA EMISSION FROM GAMMA RAYS TO THE INFRARED
... Next, the temperature, the ionization balance and the nonLTE level populations are solved for in each zone by setting up the equations for thermal and statistical equilibrium. These equations also depend on the internal radiation field, which is solved for by doing radiative transfer with a Mo ...
... Next, the temperature, the ionization balance and the nonLTE level populations are solved for in each zone by setting up the equations for thermal and statistical equilibrium. These equations also depend on the internal radiation field, which is solved for by doing radiative transfer with a Mo ...
THE HOBBY-EBERLY TELESCOPE CHEMICAL ABUNDANCES OF
... It was first proposed by Cameron (1955) and Cameron & Fowler (1971) that 7Li could be synthesized via the 3He(, )7Be and 7Be(e)7Li reactions during the late stages of stellar evolution, when a star is ascending the asymptotic giant branch (AGB). Here the outer convection zone extends down into t ...
... It was first proposed by Cameron (1955) and Cameron & Fowler (1971) that 7Li could be synthesized via the 3He(, )7Be and 7Be(e)7Li reactions during the late stages of stellar evolution, when a star is ascending the asymptotic giant branch (AGB). Here the outer convection zone extends down into t ...
Synthetic Stellar Populations Encyclopedia of Astronomy & Astrophysics eaa.iop.org Guy Worthey
... post-main-sequence stars. All of these stars have nearly the same mass (because post-main-sequence lifetimes are relatively short) so there is little mass differential for the IMF to work on. Since we do not know how much the IMF varies from environment to environment there is corresponding uncertai ...
... post-main-sequence stars. All of these stars have nearly the same mass (because post-main-sequence lifetimes are relatively short) so there is little mass differential for the IMF to work on. Since we do not know how much the IMF varies from environment to environment there is corresponding uncertai ...
Chapter 11. Stellar Brightness, Magnitudes, the Distance
... extremely hot only because they were once the core of the star and have not yet cooled off substantially. We will discuss them in greater detail later. They are very small, with radii approximately equal to the radius of the Earth! Masses of stars vary systematically across the H-R diagram. Along th ...
... extremely hot only because they were once the core of the star and have not yet cooled off substantially. We will discuss them in greater detail later. They are very small, with radii approximately equal to the radius of the Earth! Masses of stars vary systematically across the H-R diagram. Along th ...
Star Formation Regions and Planetary Nebulae
... star formation, the diffuse ISM, active galactic nuclei, and planetary nebulae – or anywhere the flux of FUV photons is large enough to influence the heating and chemistry of the region. Such regions emit nearly all of the far infrared emission in the Galaxy and comprise most of the mass. Detailed m ...
... star formation, the diffuse ISM, active galactic nuclei, and planetary nebulae – or anywhere the flux of FUV photons is large enough to influence the heating and chemistry of the region. Such regions emit nearly all of the far infrared emission in the Galaxy and comprise most of the mass. Detailed m ...
astro-ph/9505110 PDF
... Since Dufour's review there have been a number of studies devoted to obtaining high quality spectroscopy of H II regions in irregulars, particularly with regard to improving the precision in Yp (e.g., Pagel et al 1992, Terlevich et al. 1991 Spectrophotometric Catalogue of H II Galaxies; Skillman et ...
... Since Dufour's review there have been a number of studies devoted to obtaining high quality spectroscopy of H II regions in irregulars, particularly with regard to improving the precision in Yp (e.g., Pagel et al 1992, Terlevich et al. 1991 Spectrophotometric Catalogue of H II Galaxies; Skillman et ...
ppt
... Measurements of - or upper limits on - the stellar continuum constrains the IMF Sources expected to cover a range of metallicity from Z ~ 0 to 10-3 ...
... Measurements of - or upper limits on - the stellar continuum constrains the IMF Sources expected to cover a range of metallicity from Z ~ 0 to 10-3 ...
Insights into thermonuclear supernovae from the incomplete Si
... network for given thermal and structural (density) time profile, and for initial composition. The inputs to CRANK are the nuclear data and the thermodynamic trajectories, as a function of time. The thermodynamic trajectories, in turn, can be the result of a hydrodynamic calculation of an explosive e ...
... network for given thermal and structural (density) time profile, and for initial composition. The inputs to CRANK are the nuclear data and the thermodynamic trajectories, as a function of time. The thermodynamic trajectories, in turn, can be the result of a hydrodynamic calculation of an explosive e ...
What is Matter? Lesson Objectives The student will: define matter
... different substances present, each with the same properties that it had before it was mixed. When substances do not mix thoroughly and evenly (like sand and gravel), the mixture is said to be heterogeneous. A heterogeneous mixture consists of visibly different substances. Another example of a mixtur ...
... different substances present, each with the same properties that it had before it was mixed. When substances do not mix thoroughly and evenly (like sand and gravel), the mixture is said to be heterogeneous. A heterogeneous mixture consists of visibly different substances. Another example of a mixtur ...
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.