spatially resolved star formation history of milky way satellites
... dwarf galaxies and apply our method to the case of the Carina dSph galaxy. The first section of the work presents a high quality photometric catalogue of Milky Way satellites in the outer Halo. This catalogue will then provide important information about the structural properties and stellar populat ...
... dwarf galaxies and apply our method to the case of the Carina dSph galaxy. The first section of the work presents a high quality photometric catalogue of Milky Way satellites in the outer Halo. This catalogue will then provide important information about the structural properties and stellar populat ...
Richard Congdon. pdf
... A star begins life as a cloud of hydrogen and helium gas which collapses under gravity, in doing so the individual atoms gain kinetic energy from their gravitational potential energy and so increase their temperature. When the temperature is high enough fusion occurs between the hydrogen atoms and t ...
... A star begins life as a cloud of hydrogen and helium gas which collapses under gravity, in doing so the individual atoms gain kinetic energy from their gravitational potential energy and so increase their temperature. When the temperature is high enough fusion occurs between the hydrogen atoms and t ...
Non-spherical core collapse supernovae-I. Neutrino
... which link observable features at very large radii to the actual energy source and the mechanism of the explosion. Without such models, interpretation of observational data requires caution. With the present work, which is the first in a series of papers on non-spherical core collapse supernova evol ...
... which link observable features at very large radii to the actual energy source and the mechanism of the explosion. Without such models, interpretation of observational data requires caution. With the present work, which is the first in a series of papers on non-spherical core collapse supernova evol ...
Grosdidier et al. 1998
... 1. Concluding a six year effort, Fulbright et al. (2006) develop a new iron abundance scale for the bulge. A new line list of weak iron lines, with Arcturus-based gf values, is used to verify the abundance scale at the metal rich end. 2. Fulbright et al. (2007) confirms original abundance trends (en ...
... 1. Concluding a six year effort, Fulbright et al. (2006) develop a new iron abundance scale for the bulge. A new line list of weak iron lines, with Arcturus-based gf values, is used to verify the abundance scale at the metal rich end. 2. Fulbright et al. (2007) confirms original abundance trends (en ...
White dwarfs, black holes and neutron stars in close binaries
... and the star reaches a new thermal equilibrium. In the meantime a hydrogen-burning shell has formed around the core, and the outer envelope of the star has expanded to giant dimensions. After the helium fuel in the core is exhausted in its turn, the process repeats and during subsequent stages, heav ...
... and the star reaches a new thermal equilibrium. In the meantime a hydrogen-burning shell has formed around the core, and the outer envelope of the star has expanded to giant dimensions. After the helium fuel in the core is exhausted in its turn, the process repeats and during subsequent stages, heav ...
The Current Status of Galaxy Formation
... subsequent star formation (see Fig. 6). The abrupt increase of the sound speed to ∼ 10 − 20 km/s at z ∼ 10 means that dwarfs of halo mass ∼ 106 − 107 M , which have not yet collapsed and fragmented into stars, will be disrupted. However massive dwarfs are unaffected, as are the high σ peaks that de ...
... subsequent star formation (see Fig. 6). The abrupt increase of the sound speed to ∼ 10 − 20 km/s at z ∼ 10 means that dwarfs of halo mass ∼ 106 − 107 M , which have not yet collapsed and fragmented into stars, will be disrupted. However massive dwarfs are unaffected, as are the high σ peaks that de ...
Ultra-luminous Quasars with the Most Massive Black Holes at
... Figure 1. Detection of X-ray emission of J0100+2802. Left: 1′ × 1′ Chandra image centered on J0100+2802 in 0.5–7 keV. The circles show the two sources detected by CIAO task WAVDETECT; Middle: central 10″ × 10″ of the image. The plus sign shows the optical position given by SDSS. 14 counts are detect ...
... Figure 1. Detection of X-ray emission of J0100+2802. Left: 1′ × 1′ Chandra image centered on J0100+2802 in 0.5–7 keV. The circles show the two sources detected by CIAO task WAVDETECT; Middle: central 10″ × 10″ of the image. The plus sign shows the optical position given by SDSS. 14 counts are detect ...
Galactic Evolution of Silicon Isotopes: Applications to
... Zinner 1993 and references therein). The anomalous isotopes and the almost pure s-process xenon mark these presolar SiC grains as having formed from ejecta rich in the nucleosynthesis products of a single star. The name STARDUST has been suggested for high-quality single grains grown in stellar wind ...
... Zinner 1993 and references therein). The anomalous isotopes and the almost pure s-process xenon mark these presolar SiC grains as having formed from ejecta rich in the nucleosynthesis products of a single star. The name STARDUST has been suggested for high-quality single grains grown in stellar wind ...
The impact of surface temperature inhomogeneities on quiescent
... 2011; Antoniadis et al. 2013; Ransom et al. 2014), it is difficult to determine the NS radius. One method for determining the size of a NS is through a modification of the blackbody radius method (van Paradijs 1979): if the distance, flux and temperature of a perfect blackbody sphere can be measured ...
... 2011; Antoniadis et al. 2013; Ransom et al. 2014), it is difficult to determine the NS radius. One method for determining the size of a NS is through a modification of the blackbody radius method (van Paradijs 1979): if the distance, flux and temperature of a perfect blackbody sphere can be measured ...
Article PDF - IOPscience
... to Mattila et al. (2007), Kankare et al. (2008, 2012), Väisänen et al. (2008a, 2008b), and Randriamanakoto et al. (2013) for details of observations and data reduction. 2.1. Photometry and SSC Selection The SSC candidate photometric catalogs were generated by following the same steps as in Randria ...
... to Mattila et al. (2007), Kankare et al. (2008, 2012), Väisänen et al. (2008a, 2008b), and Randriamanakoto et al. (2013) for details of observations and data reduction. 2.1. Photometry and SSC Selection The SSC candidate photometric catalogs were generated by following the same steps as in Randria ...
ABSTRACT Stellar feedback, star formation and
... thermal feedback and photoelectric heating. The results are compared with the three previous simulations in this series which consists of a model with no star formation, star formation but no form of feedback and star formation with photoelectric heating in a set with steadily increasing physical ef ...
... thermal feedback and photoelectric heating. The results are compared with the three previous simulations in this series which consists of a model with no star formation, star formation but no form of feedback and star formation with photoelectric heating in a set with steadily increasing physical ef ...
Progenitor systems of Type Ia Supernovae: mergers of white dwarfs
... galaxy NGC 4526. The supernova is as bright as the center of the galaxy. In the explosion itself temperatures of several billion Kelvin are reached that lead to explosive nucleosynthesis. This way, supernovae have produced virtually all heavy elements and thus shaped the Universe. As supernovae are ...
... galaxy NGC 4526. The supernova is as bright as the center of the galaxy. In the explosion itself temperatures of several billion Kelvin are reached that lead to explosive nucleosynthesis. This way, supernovae have produced virtually all heavy elements and thus shaped the Universe. As supernovae are ...
Red Supergiants and Extinction Law in the Large Magelanic Cloud
... The great advantage of the method lays in its differentiallity. In practice, there is no need to know how big the real extinctions are. Among the strengths of the method is the possibility to obtain true extinction curve if an appropriate pairs are chosen. The canceling of the Galactic extinction du ...
... The great advantage of the method lays in its differentiallity. In practice, there is no need to know how big the real extinctions are. Among the strengths of the method is the possibility to obtain true extinction curve if an appropriate pairs are chosen. The canceling of the Galactic extinction du ...
Galactic Evolution of Silicon Isotopes: Application to Presolar SiC
... Type II supernovae are the principle origin site of the vast majority of the chemical elements, including the silicon isotopes. Typically, the matter ejected contains about 10 times as many atoms of a given heavy element than did the initial matter of the massive star. Type Ia supernovae can a ect t ...
... Type II supernovae are the principle origin site of the vast majority of the chemical elements, including the silicon isotopes. Typically, the matter ejected contains about 10 times as many atoms of a given heavy element than did the initial matter of the massive star. Type Ia supernovae can a ect t ...
IRC −10414: a bow-shock-producing red supergiant star
... through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Betelgeuse and μ Cep, are known to date. In this paper, we report the discovery of an arc-like neb ...
... through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Betelgeuse and μ Cep, are known to date. In this paper, we report the discovery of an arc-like neb ...
The APEX-CHAMP+ view of the Orion Molecular Cloud 1 core
... molecular ISM under a range of assumptions (Bloemen et al. 1984; Dame & Thaddeus 1985). However, in massive star forming regions with much higher densities and temperatures, observations of the submillimeter and far-infrared (FIR) wavelength mid- or high-J transitions of 12 CO and its 13 C and 18 O ...
... molecular ISM under a range of assumptions (Bloemen et al. 1984; Dame & Thaddeus 1985). However, in massive star forming regions with much higher densities and temperatures, observations of the submillimeter and far-infrared (FIR) wavelength mid- or high-J transitions of 12 CO and its 13 C and 18 O ...
Resources: - Real Science
... people who work together the parts something is made of any of 88 groups of stars that seem to form patterns in the night sky to do with the universe as a whole pieces of information; measurements packed closely together work out; decide cause to fade away change the shape away from the normal ...
... people who work together the parts something is made of any of 88 groups of stars that seem to form patterns in the night sky to do with the universe as a whole pieces of information; measurements packed closely together work out; decide cause to fade away change the shape away from the normal ...
Tracers of Discs and Winds around Intermediate and High Mass
... the original references to take account of revised distances. For sources where an accurate spectral type can be inferred we have given that. For those where only a bolometric luminosity exists (generally the most heavily embedded) we have quoted that instead. All of these sources were chosen to be ...
... the original references to take account of revised distances. For sources where an accurate spectral type can be inferred we have given that. For those where only a bolometric luminosity exists (generally the most heavily embedded) we have quoted that instead. All of these sources were chosen to be ...
Lithium abundances in nearby FGK dwarf and subgiant stars
... The data set analyzed in this work consists of about 700 high resolution (R = λ/∆λ & 45, 000), high signalto-noise ratio (S/N & 100) spectra of 671 nearby (d < 200 pc) FGK dwarf and subgiant stars taken from the RAL study. The high quality of these data allows a precise determination of lithium abun ...
... The data set analyzed in this work consists of about 700 high resolution (R = λ/∆λ & 45, 000), high signalto-noise ratio (S/N & 100) spectra of 671 nearby (d < 200 pc) FGK dwarf and subgiant stars taken from the RAL study. The high quality of these data allows a precise determination of lithium abun ...
Galaxies
... The final galaxy class identified by Hubble—irregular galaxies—named in this way because their visual appearance does not allow us to place them into any of the other categories just discussed. Irregulars tend to be rich in interstellar matter and young, blue stars, but they lack any regular structu ...
... The final galaxy class identified by Hubble—irregular galaxies—named in this way because their visual appearance does not allow us to place them into any of the other categories just discussed. Irregulars tend to be rich in interstellar matter and young, blue stars, but they lack any regular structu ...
Non-thermal emission processes in massive binaries*
... Abstract In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even though the discussion will start in the radio domain where the non-thermal emission was ...
... Abstract In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even though the discussion will start in the radio domain where the non-thermal emission was ...
talk at lensing and dark matter conference Ohio state 2004
... RR Lyaes and discovered an old and hot stellar halo! But they say it is too small to account for all the extra microlensing • But the structure of the LMC is being questioned: van der Marel,et al (2002) says the LMC disk is not circular, but Nikolaev, et al. (2004) disagree, saying it is warped. Bot ...
... RR Lyaes and discovered an old and hot stellar halo! But they say it is too small to account for all the extra microlensing • But the structure of the LMC is being questioned: van der Marel,et al (2002) says the LMC disk is not circular, but Nikolaev, et al. (2004) disagree, saying it is warped. Bot ...
Chemical evolution models for the dwarf spheroidal galaxies Leo 1
... the processes which played a major role on the evolution of these two galaxies would provide very important clues in the study of dSph galaxies as a whole. Similar to other nearby dSph galaxies, they are characterized by low metallicities and exhibit the same α-element deficiency at high metalliciti ...
... the processes which played a major role on the evolution of these two galaxies would provide very important clues in the study of dSph galaxies as a whole. Similar to other nearby dSph galaxies, they are characterized by low metallicities and exhibit the same α-element deficiency at high metalliciti ...
edmund c. stoner and the discovery of the maximum mass of white
... to the pressure given by the extreme relativistic equation at the same density. For a larger mass, he applied this relativistic equation to a central region of the star, and the non-relativistic equation for an external region of the star bounded by a surface defined when these two equations gave the ...
... to the pressure given by the extreme relativistic equation at the same density. For a larger mass, he applied this relativistic equation to a central region of the star, and the non-relativistic equation for an external region of the star bounded by a surface defined when these two equations gave the ...
Dust input from AGB stars in the Large Magellanic Cloud
... supersonic outflow occurs rather close to the star where temperatures are too high for dust formation. In regions where temperatures become low enough for condensation, the density in the stellar outflow is already too low for substantial dust growth. Gail et al. (2009) also considered dust condensa ...
... supersonic outflow occurs rather close to the star where temperatures are too high for dust formation. In regions where temperatures become low enough for condensation, the density in the stellar outflow is already too low for substantial dust growth. Gail et al. (2009) also considered dust condensa ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.