13.1 Introduction 13.2 The Red Giant Branch
... Table 13.1 gives some representative values for the sizes and luminosities of red giant stars; a main sequence G V star may end up as a high-K or low-M luminosity class III giant. Note that the values in Table 13.1 depend largely on the spectral type, and not on the mass: stars of a wide range of ma ...
... Table 13.1 gives some representative values for the sizes and luminosities of red giant stars; a main sequence G V star may end up as a high-K or low-M luminosity class III giant. Note that the values in Table 13.1 depend largely on the spectral type, and not on the mass: stars of a wide range of ma ...
SPY — The ESO Supernovae Type Ia Progenitor Survey
... of spectra, which have to be checked for RV variations, a fast and reliable algorithm to measure RV shifts is necessary. We apply a “cross-correlation” routine based on a χ2 test (description in Napiwotzki et al. 2001). The RV shift is evaluated from the minimum χ2. Error margins can be estimated fr ...
... of spectra, which have to be checked for RV variations, a fast and reliable algorithm to measure RV shifts is necessary. We apply a “cross-correlation” routine based on a χ2 test (description in Napiwotzki et al. 2001). The RV shift is evaluated from the minimum χ2. Error margins can be estimated fr ...
The self-enrichment of galactic halo globular clusters: a clue to their
... giant branch. Dopita and Smith (1986) have already addressed the first point from a purely dynamical point of view. In their model, they assume the simultaneity of central supernova explosions and they use the Kompaneets (1960) approximation to describe the resulting blast wave motion. During this p ...
... giant branch. Dopita and Smith (1986) have already addressed the first point from a purely dynamical point of view. In their model, they assume the simultaneity of central supernova explosions and they use the Kompaneets (1960) approximation to describe the resulting blast wave motion. During this p ...
The Helium Flash • When the temperature of a stellar core reaches T
... Note: the core mass at ignition is somewhat dependent on the star’s initial helium abundance, weakly dependent on its initial metallicity, and surprisingly insensitive to the star’s initial mass. In general, helium burning for all stars begins when the core reaches ∼ 0.45M⊙ . • Stars with degenerate ...
... Note: the core mass at ignition is somewhat dependent on the star’s initial helium abundance, weakly dependent on its initial metallicity, and surprisingly insensitive to the star’s initial mass. In general, helium burning for all stars begins when the core reaches ∼ 0.45M⊙ . • Stars with degenerate ...
Globular Clusters Dynamic Lives The
... integrated star clusters along with some dwarf satellite galaxies. The 150 or so globulars surviving today are probably just a small fraction of those that once populated the galactic halo. Tidal shocks can also accelerate the evolution of clusters toward core collapse. Whether a cluster will evapor ...
... integrated star clusters along with some dwarf satellite galaxies. The 150 or so globulars surviving today are probably just a small fraction of those that once populated the galactic halo. Tidal shocks can also accelerate the evolution of clusters toward core collapse. Whether a cluster will evapor ...
Review: How does a star`s mass determine its life story?
... A. It would orbit indefinitely. B. It would eventually fall in. C. It would blow away. ...
... A. It would orbit indefinitely. B. It would eventually fall in. C. It would blow away. ...
Massive star evolution: luminous blue variables as unexpected
... explosion. We performed coupled stellar evolution and atmospheric modeling of stars with initial masses between 20 M and 120 M . We found that the 20 M and 25 M rotating models, before exploding as SN, have spectra that do not resemble any of the aforementioned classes of massive stars. Rather, ...
... explosion. We performed coupled stellar evolution and atmospheric modeling of stars with initial masses between 20 M and 120 M . We found that the 20 M and 25 M rotating models, before exploding as SN, have spectra that do not resemble any of the aforementioned classes of massive stars. Rather, ...
Ch. 19 - Astro1010
... Often as a large star ages much of the fuel is used up and deposited as ‘ash’ in the iron core. The inward pressure on the iron core is enormous, due to the high mass of the star. As the core continues to become more and more dense, the protons react with one another to become neutrons + a flood of ...
... Often as a large star ages much of the fuel is used up and deposited as ‘ash’ in the iron core. The inward pressure on the iron core is enormous, due to the high mass of the star. As the core continues to become more and more dense, the protons react with one another to become neutrons + a flood of ...
THE OUTER STRUCTURE OF GALACTIC DISCS 1
... formation time-scales are comparable. Governato et al. [5] have incorporated star formation into disc formation in a cosmological framework. But the dozens of articles on disc formation between these dates do not show that exponentiality is a fundamental disc property. Perhaps most surprisingly many ...
... formation time-scales are comparable. Governato et al. [5] have incorporated star formation into disc formation in a cosmological framework. But the dozens of articles on disc formation between these dates do not show that exponentiality is a fundamental disc property. Perhaps most surprisingly many ...
THE YELLOW SUPERGIANT PROGENITOR OF THE TYPE II
... panel: the spectroscopic evolution of SN 2011dh. Blue (dashed) lines mark the He i λλ6678, 7065, 7281 lines. Red (dotted) lines mark Hα at the rest wavelength and at −12, 500 km s−1 . All spectra and photometry have been corrected for reddening using the extinction law of Cardelli et al. (1989) and ...
... panel: the spectroscopic evolution of SN 2011dh. Blue (dashed) lines mark the He i λλ6678, 7065, 7281 lines. Red (dotted) lines mark Hα at the rest wavelength and at −12, 500 km s−1 . All spectra and photometry have been corrected for reddening using the extinction law of Cardelli et al. (1989) and ...
Tasks - ESA Science
... surrounding space at the speed of light, c. Later, at some time, t seconds after the explosion, the flash will illuminate the ring. Since we have assumed that the ring is circular and we will also assume that its centre coincides with that of the supernova, all parts of the ring will be illuminated ...
... surrounding space at the speed of light, c. Later, at some time, t seconds after the explosion, the flash will illuminate the ring. Since we have assumed that the ring is circular and we will also assume that its centre coincides with that of the supernova, all parts of the ring will be illuminated ...
The masses of stars
... to counteract it; the increased rate of nuclear fusion both raises its central temperature and releases more energy to make the star shine more brightly. Supergiants are more massive than the red giants, which are in turn more massive than white dwarfs; but unlike for stars on the main sequence, th ...
... to counteract it; the increased rate of nuclear fusion both raises its central temperature and releases more energy to make the star shine more brightly. Supergiants are more massive than the red giants, which are in turn more massive than white dwarfs; but unlike for stars on the main sequence, th ...
Document
... - Due to lack of mass carbon will not be able to condense enough to fuse into oxygen. - After Planetary Nebula Gases Spread out all that remains is a ...
... - Due to lack of mass carbon will not be able to condense enough to fuse into oxygen. - After Planetary Nebula Gases Spread out all that remains is a ...
Binary progenitor models of type IIb supernovae
... signature of hydrogen is found – are thought to result from massive stars that have lost their entire hydrogen-rich envelope. Type IIb supernovae constitute an intriguing intermediate case. Initially they show clear evidence for hydrogen, but later the hydrogen lines become weak or absent in the spe ...
... signature of hydrogen is found – are thought to result from massive stars that have lost their entire hydrogen-rich envelope. Type IIb supernovae constitute an intriguing intermediate case. Initially they show clear evidence for hydrogen, but later the hydrogen lines become weak or absent in the spe ...
stars - acpsd
... for new stars begins in the Main Sequence. These mature stars undergo a remarkable transformation after they consume all the hydrogen in their core. With the hydrogen consumed, stars leave the main sequence and expand to form red giants. With this new stage, the fusion of helium begins to form heavi ...
... for new stars begins in the Main Sequence. These mature stars undergo a remarkable transformation after they consume all the hydrogen in their core. With the hydrogen consumed, stars leave the main sequence and expand to form red giants. With this new stage, the fusion of helium begins to form heavi ...
Pre-supernova evolution of massive stars
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached is smaller than required for carbon fusion. During the latest stages of evolution on the AG ...
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached is smaller than required for carbon fusion. During the latest stages of evolution on the AG ...
Mass loss of massive stars near the Eddington luminosity by core
... 20 M red supergiant with a 4 M carbon+oxygen core, while the 50 M star has become a 22 M star with a 15 M carbon+oxygen core and a helium-rich layer outside. Figure 1 presents the neutrino luminosities obtained from the stellar evolution models. Most of neutrinos are thermally emitted and the l ...
... 20 M red supergiant with a 4 M carbon+oxygen core, while the 50 M star has become a 22 M star with a 15 M carbon+oxygen core and a helium-rich layer outside. Figure 1 presents the neutrino luminosities obtained from the stellar evolution models. Most of neutrinos are thermally emitted and the l ...
Chapter 12 Lecture 2
... Hydrogen fuses in shell around core Helium fusion slowly begins Helium fusion rate rapidly rises ...
... Hydrogen fuses in shell around core Helium fusion slowly begins Helium fusion rate rapidly rises ...
Red Supergiants, Luminous Blue Variables and Wolf
... blue part of the HR diagram due in part to the presence of dust and to various instabilities active in red supergiant atmospheres (e.g. convection becomes supersonic and turbulent pressure can no longer be ignored). An illustration of the difficulty comes from the determinations of red supergiant ma ...
... blue part of the HR diagram due in part to the presence of dust and to various instabilities active in red supergiant atmospheres (e.g. convection becomes supersonic and turbulent pressure can no longer be ignored). An illustration of the difficulty comes from the determinations of red supergiant ma ...
Chapter 12: The Life Cycle of Stars (contʼd)
... • Process continues up to the formation of iron. ...
... • Process continues up to the formation of iron. ...
C/O core
... Internal stratification: the C/O core The heat capacity is dominated by C/O ions The amounts of C and O left in the core have a great influence on the WD cooling rate The larger O content ...
... Internal stratification: the C/O core The heat capacity is dominated by C/O ions The amounts of C and O left in the core have a great influence on the WD cooling rate The larger O content ...
mass loss of massive stars - of /proceedings
... of luminosity for a sample of red supergiant studied by Mauron & Josselin (2011). Two key features are seen. First, there seems to be a trend of higher mass loss rates for higher luminosities. Second, at a given luminosity, the dispersion in mass loss rates is about a factor of ten. Mauron & Josseli ...
... of luminosity for a sample of red supergiant studied by Mauron & Josselin (2011). Two key features are seen. First, there seems to be a trend of higher mass loss rates for higher luminosities. Second, at a given luminosity, the dispersion in mass loss rates is about a factor of ten. Mauron & Josseli ...
Post-Main Sequence Evolution – Low and Intermediate Mass Stars
... burning during the flash reaches about 1010 solar luminosities, equivalent to a small galaxy. But very little helium burns before expansion puts out the runaway after only a few minutes (a factor of a few times the sound crossing time for the helium core). This large luminosity does not arrive at th ...
... burning during the flash reaches about 1010 solar luminosities, equivalent to a small galaxy. But very little helium burns before expansion puts out the runaway after only a few minutes (a factor of a few times the sound crossing time for the helium core). This large luminosity does not arrive at th ...
Supernova
A supernova is a stellar explosion that briefly outshines an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire life span, before fading from view over several weeks or months. The extremely luminous burst of radiation expels much or all of a star's material at a velocity of up to 7007300000000000000♠30,000 km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. Supernovae are potentially strong galactic sources of gravitational waves. A great proportion of primary cosmic rays comes from supernovae.Supernovae are more energetic than novae. Nova means ""new"" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix ""super-"" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1931. It is pronounced /ˌsuːpərnoʊvə/ with the plural supernovae /ˌsuːpərnoʊviː/ or supernovas (abbreviated SN, plural SNe after ""supernovae"").Supernovae can be triggered in one of two ways: by the sudden re-ignition of nuclear fusion in a degenerate star; or by the gravitational collapse of the core of a massive star. In the first case, a degenerate white dwarf may accumulate sufficient material from a companion, either through accretion or via a merger, to raise its core temperature, ignite carbon fusion, and trigger runaway nuclear fusion, completely disrupting the star. In the second case, the core of a massive star may undergo sudden gravitational collapse, releasing gravitational potential energy that can create a supernova explosion.The most recent directly observed supernova in the Milky Way was Kepler's Star of 1604 (SN 1604); remnants of two more recent supernovae have been found retrospectively. Observations in other galaxies indicate that supernovae should occur on average about three times every century in the Milky Way, and that any galactic supernova would almost certainly be observable in modern astronomical equipment. Supernovae play a significant role in enriching the interstellar medium with higher mass elements. Furthermore, the expanding shock waves from supernova explosions can trigger the formation of new stars.