Systematic Study of Mass Loss in the Evolution of Massive Stars
... As for all stars, massive stars are globally hydrostatic and at thermal equilibrium, selfgravitating, gaseous structures. Their evolution is governed by the consumption of nuclear fuel in the inner regions, which balances the energy loss from the surface with the energy ...
... As for all stars, massive stars are globally hydrostatic and at thermal equilibrium, selfgravitating, gaseous structures. Their evolution is governed by the consumption of nuclear fuel in the inner regions, which balances the energy loss from the surface with the energy ...
the harps-terra project. i. description of the algorithms, performance
... deconvolution of observations without iodine is a key element of the method and is thought to be one of its major limitations (e.g., see supplementary material in Howard et al. 2010). The other leading method of obtaining precision RV measurements consists of building a fiber-fed, very stable spectr ...
... deconvolution of observations without iodine is a key element of the method and is thought to be one of its major limitations (e.g., see supplementary material in Howard et al. 2010). The other leading method of obtaining precision RV measurements consists of building a fiber-fed, very stable spectr ...
The X-shooter Spectral Library (XSL): I. DR1. Near
... plane (and, as a consequence, also surface gravity–effective temperature) of stars with different masses, the same initial chemical composition, and age; an initial mass function that populates the isochrones with a sensible number of stars; and a stellar library. A spectral library is a collection ...
... plane (and, as a consequence, also surface gravity–effective temperature) of stars with different masses, the same initial chemical composition, and age; an initial mass function that populates the isochrones with a sensible number of stars; and a stellar library. A spectral library is a collection ...
CHEMICAL ABUNDANCE DISTRIBUTIONS OF GALACTIC HALOS
... cold gas into each satellite is followed from the epoch of reionization to the time of its accretion onto the main halo. The gas mass is translated into a stellar mass through a simple star formation prescription (see Robertson et al. 2005 and x 2.2 for more details). Star formation ceases soon afte ...
... cold gas into each satellite is followed from the epoch of reionization to the time of its accretion onto the main halo. The gas mass is translated into a stellar mass through a simple star formation prescription (see Robertson et al. 2005 and x 2.2 for more details). Star formation ceases soon afte ...
Galactic spiral structure - Proceedings of the Royal Society A
... A clear indication of the stability of stream motions is given by the velocity distribution for old stars, using isochrone ages given by G-CS II (figure 9). There are known problems with isochrone ageing for very young stars; we found that a number of stars with young kinematics had been assigned age ...
... A clear indication of the stability of stream motions is given by the velocity distribution for old stars, using isochrone ages given by G-CS II (figure 9). There are known problems with isochrone ageing for very young stars; we found that a number of stars with young kinematics had been assigned age ...
Link
... and the properties of gas in nearby associations provide clues about the history of star formation and the origin, evolution, and destruction of molecular clouds over the last 100 Myr. Such studies enable us to decode the recent history of the interstellar medium and associated star birth in our por ...
... and the properties of gas in nearby associations provide clues about the history of star formation and the origin, evolution, and destruction of molecular clouds over the last 100 Myr. Such studies enable us to decode the recent history of the interstellar medium and associated star birth in our por ...
Shock interactions, turbulence and the origin of the stellar mass
... show that the data are indeed consistent with a single Kolmogorov spectrum over the full range of length scales. The ratio of the largest to smallest length scales increases like Re3/4 , where Re is the Reynolds number. Thus, these astrophysical flows must have an extremely high Reynolds number of a ...
... show that the data are indeed consistent with a single Kolmogorov spectrum over the full range of length scales. The ratio of the largest to smallest length scales increases like Re3/4 , where Re is the Reynolds number. Thus, these astrophysical flows must have an extremely high Reynolds number of a ...
Polaris B, an optical companion of the Polaris (αUMi) system
... with difficulties in his photometrical observations when the scattered light from the primary component ‘. . .appreciably contaminated the light of the eight magnitude secondary. . .under the relatively poor seeing conditions that prevail in this climate’. Afterwards Kamper (1996) noted that fibre-l ...
... with difficulties in his photometrical observations when the scattered light from the primary component ‘. . .appreciably contaminated the light of the eight magnitude secondary. . .under the relatively poor seeing conditions that prevail in this climate’. Afterwards Kamper (1996) noted that fibre-l ...
Manual for Visual Observing of Variable Stars
... Observing of Variable Stars. This manual is intended to be a comprehensive guide to variable star observing. It incorporates a lot of the basic information in the Manual for Observing Variable Stars, published in 1970 by the former Director of the AAVSO, Margaret W. Mayall, as well as information fr ...
... Observing of Variable Stars. This manual is intended to be a comprehensive guide to variable star observing. It incorporates a lot of the basic information in the Manual for Observing Variable Stars, published in 1970 by the former Director of the AAVSO, Margaret W. Mayall, as well as information fr ...
Further VLBA Observations of SiO Masers toward Mira
... Asymptotic Giant Branch (AGB) where the inner core of the star has collapsed and the outer envelope has become very extended and is in the process of losing its mass to the interstellar medium through pulsational instabilities. In the cool, extended envelopes of these stars, molecules form and conde ...
... Asymptotic Giant Branch (AGB) where the inner core of the star has collapsed and the outer envelope has become very extended and is in the process of losing its mass to the interstellar medium through pulsational instabilities. In the cool, extended envelopes of these stars, molecules form and conde ...
The binary fractions in the massive young Large Magellanic Cloud
... This means that the binary system will appear as a single object with a brighter magnitude than that of the primary star. Unresolved binaries with MS primary components will thus be biased towards the brighter envelope of the MS. We used the Bressan et al. (2012) isochrones to describe our decontami ...
... This means that the binary system will appear as a single object with a brighter magnitude than that of the primary star. Unresolved binaries with MS primary components will thus be biased towards the brighter envelope of the MS. We used the Bressan et al. (2012) isochrones to describe our decontami ...
Lyman Break Galaxies at z~ 5: Luminosity Function
... Since their first discovery in the late 1990s, the Lyman break galaxies (LBGs) at z ∼ 3 have been extensively investigated in various ways and knowledge on their nature has been accumulated. Their rest UV spectra resemble those of nearby active star-forming galaxies (Steidel et al. 1996b). On-going ...
... Since their first discovery in the late 1990s, the Lyman break galaxies (LBGs) at z ∼ 3 have been extensively investigated in various ways and knowledge on their nature has been accumulated. Their rest UV spectra resemble those of nearby active star-forming galaxies (Steidel et al. 1996b). On-going ...
Astronomy Astrophysics
... we averaged all non-discarded (typically 3) signals in order to derive a signal per chopper step. Due to detector transient effects, at the beginning of the observation the derived signals were systematically lower than those in the consolidated part of the measurement. We then discarded the first ∼ ...
... we averaged all non-discarded (typically 3) signals in order to derive a signal per chopper step. Due to detector transient effects, at the beginning of the observation the derived signals were systematically lower than those in the consolidated part of the measurement. We then discarded the first ∼ ...
Slide 1
... a large fraction of gas & stars tidally stripped from the dwarf galaxy during interaction leaving only stars most closely bound to the BH (GC-like) star formation triggered by tidal interactions compatible with eccentric binary scenario presence of dust lanes in ESO243-49 could provide evide ...
... a large fraction of gas & stars tidally stripped from the dwarf galaxy during interaction leaving only stars most closely bound to the BH (GC-like) star formation triggered by tidal interactions compatible with eccentric binary scenario presence of dust lanes in ESO243-49 could provide evide ...
A search for nearby counterparts to the moving objects in the Hubble
... While there are no objects in LHS with H . 24; there are a few objects in the range 24:0 . H . 23:5: A literature search using SIMBAD showed that all but one of these have been classified as either disc M dwarfs or disc white dwarfs through parallax, photometry and/or spectroscopic methods (McCook & ...
... While there are no objects in LHS with H . 24; there are a few objects in the range 24:0 . H . 23:5: A literature search using SIMBAD showed that all but one of these have been classified as either disc M dwarfs or disc white dwarfs through parallax, photometry and/or spectroscopic methods (McCook & ...
Polaris B, an optical companion of Polaris (alpha UMi) system
... A comparison of chemical abundances of the both components displays some interesting features. At about an equal (within the limits of mean errors) iron, α−, Fe-group (excepting manganese) and s-process elements abundances for the both stars, Polaris B demonstrates solar carbon content, thereas Ceph ...
... A comparison of chemical abundances of the both components displays some interesting features. At about an equal (within the limits of mean errors) iron, α−, Fe-group (excepting manganese) and s-process elements abundances for the both stars, Polaris B demonstrates solar carbon content, thereas Ceph ...
0004-637X 778 2 119
... bursts of anomalous X-ray pulsars (AXPs) and SGRs do not require magnetar (B > 1014 G) dipole fields. The properties of these two SGRs, which are likely to be older than the other known AXPs/SGRs (see Mereghetti 2008 for a recent review of AXPs/SGRs), provide tight constraints for models in explaini ...
... bursts of anomalous X-ray pulsars (AXPs) and SGRs do not require magnetar (B > 1014 G) dipole fields. The properties of these two SGRs, which are likely to be older than the other known AXPs/SGRs (see Mereghetti 2008 for a recent review of AXPs/SGRs), provide tight constraints for models in explaini ...
3 science case - Giant Magellan Telescope Organization
... method. Progress in our understanding of the cosmos often proceeds from the discovery of new classes of objects or phenomena to the painstaking confrontation between observation and theory. Astronomical discovery is driven by technology and the pace of astronomical discovery can be traced largely in ...
... method. Progress in our understanding of the cosmos often proceeds from the discovery of new classes of objects or phenomena to the painstaking confrontation between observation and theory. Astronomical discovery is driven by technology and the pace of astronomical discovery can be traced largely in ...
The evolution of massive stars and their spectra
... and photometric evolution of a non-rotating 60 M star at solar metallicity, from the zero-age main sequence (ZAMS) until the pre-SN stage. We choose a non-rotating model to properly disentangle the effects that mass loss and rotation have on the evolution of the spectra of massive stars. The reason ...
... and photometric evolution of a non-rotating 60 M star at solar metallicity, from the zero-age main sequence (ZAMS) until the pre-SN stage. We choose a non-rotating model to properly disentangle the effects that mass loss and rotation have on the evolution of the spectra of massive stars. The reason ...
POLYTROPES - Princeton
... The case n = 0 corresponds to incompressible fluid, i.e. ρ = ρc = const, P = Pc θ, and it requires rewriting eq. (poly.6) in a different form. In this case pressure vanishes at the surface, but density is the same throughout the ”star”. This solution is a crude approximation to the interior structur ...
... The case n = 0 corresponds to incompressible fluid, i.e. ρ = ρc = const, P = Pc θ, and it requires rewriting eq. (poly.6) in a different form. In this case pressure vanishes at the surface, but density is the same throughout the ”star”. This solution is a crude approximation to the interior structur ...
3 Gravitational Waves from Binaries
... strain releases in the wires that suspend the masses. This noise prevents a single interferometer, by itself, from detecting with confidence shortduration gravitational-wave bursts (though it might be possible for a single interferometer to search for the periodic waves from known pulsars). The non- ...
... strain releases in the wires that suspend the masses. This noise prevents a single interferometer, by itself, from detecting with confidence shortduration gravitational-wave bursts (though it might be possible for a single interferometer to search for the periodic waves from known pulsars). The non- ...
Chapter 7 Elliptical Galaxies Chapter 16 Elliptical Galaxies
... 7.1.4 Central regions of elliptical galaxies and bulges They are important for the dynamical structure (population of stellar orbits, see below) of ellipticals and probably all bulges and ellipticals host supermassive black holes (see below). The structure of the central regions seems intimately lin ...
... 7.1.4 Central regions of elliptical galaxies and bulges They are important for the dynamical structure (population of stellar orbits, see below) of ellipticals and probably all bulges and ellipticals host supermassive black holes (see below). The structure of the central regions seems intimately lin ...
The ROSAT galactic plane survey: ASTRONOMY AND
... Obviously, the identification of this large amount of X-ray sources is far beyond the nowadays possibilities. Accordingly, we used three different paths for exploring this unprecedented amount of new sources. The first and easiest step was the cross correlation of RGPS source positions with astronom ...
... Obviously, the identification of this large amount of X-ray sources is far beyond the nowadays possibilities. Accordingly, we used three different paths for exploring this unprecedented amount of new sources. The first and easiest step was the cross correlation of RGPS source positions with astronom ...
Influence of extreme ultraviolet radiation on the Pv ionization fraction
... on the square of the density. Moreover, the ultraviolet P V resonance lines indicate a possible need for an even stronger reduction of hot star mass-loss rates, provided that P V is a dominant ionization stage of phosphorus, at least in some hot stars. The latter assumption is challenged by the poss ...
... on the square of the density. Moreover, the ultraviolet P V resonance lines indicate a possible need for an even stronger reduction of hot star mass-loss rates, provided that P V is a dominant ionization stage of phosphorus, at least in some hot stars. The latter assumption is challenged by the poss ...
Monte Carlo simulations of the disc white dwarf population
... These restrictions determine the size of the ®nal sample, which typically is , 200 stars (hereinafter the `restricted' sample). Finally, we normalize the total density of white dwarfs obtained in this way to its observed value in the solar neighbourhood (Oswalt et al. ...
... These restrictions determine the size of the ®nal sample, which typically is , 200 stars (hereinafter the `restricted' sample). Finally, we normalize the total density of white dwarfs obtained in this way to its observed value in the solar neighbourhood (Oswalt et al. ...
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.