Chemical composition of B-type supergiants in the OB8, OB10
... Radial velocities of the OB48 stars and the OB78 stars, OB78-277 & OB78-478, agree within 10% of the radial velocities determined by Rubin & Ford (1970) for H II regions in the relevant OB associations. OB78-159 has a radial velocity significantly less than that expected from a star situated in the ...
... Radial velocities of the OB48 stars and the OB78 stars, OB78-277 & OB78-478, agree within 10% of the radial velocities determined by Rubin & Ford (1970) for H II regions in the relevant OB associations. OB78-159 has a radial velocity significantly less than that expected from a star situated in the ...
sections 4-6 instructor notes
... of the stars. The emission produced by a diffuse shell surrounding a star typically produces a P Cygni–type of profile consisting of a sharp blue absorption feature on an broad emission line. The determination of realistic systemic velocities for such stars is an ongoing problem in ...
... of the stars. The emission produced by a diffuse shell surrounding a star typically produces a P Cygni–type of profile consisting of a sharp blue absorption feature on an broad emission line. The determination of realistic systemic velocities for such stars is an ongoing problem in ...
this article
... Up to 95% of stars are LIMS (Kwok 2004). Studying the nature of dust around LIMS is important for three reasons: (1) this is where the dust originates, and thus knowing its initial state will allow us to predict more accurately its fate in and effect on the ISM and beyond; (2) the environment around ...
... Up to 95% of stars are LIMS (Kwok 2004). Studying the nature of dust around LIMS is important for three reasons: (1) this is where the dust originates, and thus knowing its initial state will allow us to predict more accurately its fate in and effect on the ISM and beyond; (2) the environment around ...
Determining the Stellar Spin Axis Orientation
... We present an observing method that permits the determination of the absolute stellar spin axis position angle based on spectro-astrometric observations for slowly-rotating late-type stars. This method is complementary to current interferometric observations that determine the orientation of stellar ...
... We present an observing method that permits the determination of the absolute stellar spin axis position angle based on spectro-astrometric observations for slowly-rotating late-type stars. This method is complementary to current interferometric observations that determine the orientation of stellar ...
v1 - ESO
... In 1936 Edwin Hubble presented his tuning fork diagram classifying the different types of galaxy to be found in the Universe. This was the first attempt to find a pattern in the properties of different systems and thus search for a common evolutionary link. Elliptical galaxies appear to be shaped pr ...
... In 1936 Edwin Hubble presented his tuning fork diagram classifying the different types of galaxy to be found in the Universe. This was the first attempt to find a pattern in the properties of different systems and thus search for a common evolutionary link. Elliptical galaxies appear to be shaped pr ...
The chemical composition of TS 01, the most oxygen
... of a factor 2. Thus the extreme O deficiency of this object is confirmed. The abundances of S and Ar are less than 1/30 of solar. The abundance of He relative to H is 0.089 ± 0.009. Standard models of stellar evolution and nucleosynthesis cannot explain the abundance pattern observed in the nebula. ...
... of a factor 2. Thus the extreme O deficiency of this object is confirmed. The abundances of S and Ar are less than 1/30 of solar. The abundance of He relative to H is 0.089 ± 0.009. Standard models of stellar evolution and nucleosynthesis cannot explain the abundance pattern observed in the nebula. ...
The Sagittarius dwarf irregular galaxy: Metallicity and stellar
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
The Sagittarius dwarf irregular galaxy: Metallicity and stellar
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
The Sagittarius dwarf irregular galaxy
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
... where the b0 , v 0 , and i0 magnitudes are the instrumental magnitudes for the standard stars, measured in apertures with radius 6.00 9, normalized to zero airmass and 1 s exposure. The instrumental PSF magnitudes of stars in the SagDIG field were converted to normalized aperture magnitudes using a ...
How Massive Single Stars End Their Life - TigerPrints
... low metallicities, the boundaries for black hole formation are also defined entirely by the initial stellar mass since there is a one-to-one correspondence between initial stellar mass and final helium core mass. For stars of higher metallicity, mass loss becomes increasingly important, resulting in s ...
... low metallicities, the boundaries for black hole formation are also defined entirely by the initial stellar mass since there is a one-to-one correspondence between initial stellar mass and final helium core mass. For stars of higher metallicity, mass loss becomes increasingly important, resulting in s ...
On the anomalous mass defect of strange stars in the Field
... defects characterized by energy excesses with respect to the energies they would have to be (stable) bound systems. Anomalous mass defects were interpreted in terms of a catastrophic additivity violation of the internal energy due to the very intense gravitational fields in the interior of such supe ...
... defects characterized by energy excesses with respect to the energies they would have to be (stable) bound systems. Anomalous mass defects were interpreted in terms of a catastrophic additivity violation of the internal energy due to the very intense gravitational fields in the interior of such supe ...
Determining distances to stars statistically from photometry
... update the software correctly, or they purposely sent back a wrong answer quickly so that they can accumulate BOINC “credit” more quickly. It is impossible to overestimate how important it is to our volunteers that they get credit for the work units their computers crunch, and that credit is apporti ...
... update the software correctly, or they purposely sent back a wrong answer quickly so that they can accumulate BOINC “credit” more quickly. It is impossible to overestimate how important it is to our volunteers that they get credit for the work units their computers crunch, and that credit is apporti ...
CBO_Paper2_UnderstandingtheStoryOfTheUniverse
... Hubble concluded that the Andromeda was not a part of the Milky Way galaxy. His analysis of Andromeda published in the “Extragalactic Nature of Nebulae” caused other astronomers to look at other galaxies. The issue with calling something as a galaxy is that there is not a concrete definition of a ga ...
... Hubble concluded that the Andromeda was not a part of the Milky Way galaxy. His analysis of Andromeda published in the “Extragalactic Nature of Nebulae” caused other astronomers to look at other galaxies. The issue with calling something as a galaxy is that there is not a concrete definition of a ga ...
Magnetic Doppler imaging of the roAp star HD 24712⋆
... may prevent us from reconstructing the fine structure of magnetic field by forcing it closer to a low-order multipolar geometry. The alternative, Tikhonov regularization, which does not introduce assumptions about the global geometry of the stellar surface structures, was only applied for reconstruc ...
... may prevent us from reconstructing the fine structure of magnetic field by forcing it closer to a low-order multipolar geometry. The alternative, Tikhonov regularization, which does not introduce assumptions about the global geometry of the stellar surface structures, was only applied for reconstruc ...
Nuclear Physics - Thierry Karsenti
... PRE-REQUISITE KNOWLEDGE: In this section you are provided with information regarding the specific pre-requisite knowledge and skills you require to start the module. Carefully look into the requirements as this will help you to decide whether you require some revision work or not. TIME REQUIRED: It ...
... PRE-REQUISITE KNOWLEDGE: In this section you are provided with information regarding the specific pre-requisite knowledge and skills you require to start the module. Carefully look into the requirements as this will help you to decide whether you require some revision work or not. TIME REQUIRED: It ...
ppt - chris.engelbrecht.nithep.ac.za
... • Distribution of ejecta material provides details of explosion and nucleosynthesis - turbulent mixing of ejecta evident in models; do we see stratification or mixing in real remnants? ...
... • Distribution of ejecta material provides details of explosion and nucleosynthesis - turbulent mixing of ejecta evident in models; do we see stratification or mixing in real remnants? ...
Carbon monoxide in clouds at low metallicity in the dwarf irregular
... Bruce G. Elmegreen1, Monica Rubio2, Deidre A. Hunter3, Celia Verdugo2, Elias Brinks4 & Andreas Schruba5 ...
... Bruce G. Elmegreen1, Monica Rubio2, Deidre A. Hunter3, Celia Verdugo2, Elias Brinks4 & Andreas Schruba5 ...
Constraints on the Production of Ultra–High
... UHECRs, the particles originate from within the light cylinder, and rotation is the source of power. We next examine whether these models can give the observed composition of cosmic rays and accelerate particles to the requisite energies, and if microphysical energy loss processes produce strong cut ...
... UHECRs, the particles originate from within the light cylinder, and rotation is the source of power. We next examine whether these models can give the observed composition of cosmic rays and accelerate particles to the requisite energies, and if microphysical energy loss processes produce strong cut ...
On the evolution and fate of supermassive stars
... holes in the cores of well-known globular clusters such as 47 Tuc and NGC 6397, are expected to be ∼ (102 − 103 ) M⊙ (De Rijcke et al. 2006). ULXs are observed in both spiral and elliptical galaxies, i.e. in environments with diverse metal abundances and star formation rates. In this paper, we focus ...
... holes in the cores of well-known globular clusters such as 47 Tuc and NGC 6397, are expected to be ∼ (102 − 103 ) M⊙ (De Rijcke et al. 2006). ULXs are observed in both spiral and elliptical galaxies, i.e. in environments with diverse metal abundances and star formation rates. In this paper, we focus ...
30.4 Gravitational collapse & early protostellar evolution I (HB)
... - Theoretically, one can define the birthline at the time where the main accretion has stopped (no infalling envelope anymore), and the pre-main . sequence star gains the main luminosity from gravitational contraction. - Compared with the theoretical evolution, for low-mass stars, this is about when ...
... - Theoretically, one can define the birthline at the time where the main accretion has stopped (no infalling envelope anymore), and the pre-main . sequence star gains the main luminosity from gravitational contraction. - Compared with the theoretical evolution, for low-mass stars, this is about when ...
galaxy evolution
... starburst galaxies are detected mainly in the infrared and not in the visible and UV. • The luminosity in the far-infrared can exceed the luminosity in the visible/near-infrared by as much as 100 times. • The large rate of star production also produces a large rate of supernovae, which leads to the ...
... starburst galaxies are detected mainly in the infrared and not in the visible and UV. • The luminosity in the far-infrared can exceed the luminosity in the visible/near-infrared by as much as 100 times. • The large rate of star production also produces a large rate of supernovae, which leads to the ...
SHELL BURNING STARS: Red Giants and Red Supergiants
... products, while the other 50% is in the outer helium core. At this time we have two nuclear shell sources: hydrogen and helium. Initially, helium burning proceeds more rapidly, and most of the outer helium core is burnt into carbon and oxygen. The helium burning shell catches up with the hydrogen bu ...
... products, while the other 50% is in the outer helium core. At this time we have two nuclear shell sources: hydrogen and helium. Initially, helium burning proceeds more rapidly, and most of the outer helium core is burnt into carbon and oxygen. The helium burning shell catches up with the hydrogen bu ...
Cosmo-PST
... a. Electrons have a negative charge and cannot exist in a positive environment. b. The average photon energy was too low to produce more protons and neutrons, and too high to produce electrons. c. Protons and neutrons move slower than electrons and had fewer collisions with high-energy photons. d. E ...
... a. Electrons have a negative charge and cannot exist in a positive environment. b. The average photon energy was too low to produce more protons and neutrons, and too high to produce electrons. c. Protons and neutrons move slower than electrons and had fewer collisions with high-energy photons. d. E ...
nuclear physics - Thierry Karsenti
... to abide by the recommendations made on the basis of the mark obtained by the learner. As their instructor you should encourage learners to evaluate themselves by answering all the questions provided below. Education research shows that this will help learners be more prepared and help them articula ...
... to abide by the recommendations made on the basis of the mark obtained by the learner. As their instructor you should encourage learners to evaluate themselves by answering all the questions provided below. Education research shows that this will help learners be more prepared and help them articula ...
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.