Accretion and Current Discs Controlled by Strong Magnetic Field
... interaction of a neutron star with a surrounding disc: accretor, propeller, and ejector [15-17]. If the inner radius of the disc is beyond the corotation radius, but smaller than the light cylinder radius, the system is expected to be in the propeller stage (a neutron star rotation is strong enough ...
... interaction of a neutron star with a surrounding disc: accretor, propeller, and ejector [15-17]. If the inner radius of the disc is beyond the corotation radius, but smaller than the light cylinder radius, the system is expected to be in the propeller stage (a neutron star rotation is strong enough ...
Chemical abundances and winds of massive stars in M31: a B
... been carried out to date. The only detailed studies of WolfRayet stars beyond the Magellanic Clouds have been studies of late WN stars in M33 by Smith et al. (1997) and Crowther et al. (1997). Bianchi et al. (1994) have published UV spectroscopy of OB-type supergiants in M31 and M33, while Monteverd ...
... been carried out to date. The only detailed studies of WolfRayet stars beyond the Magellanic Clouds have been studies of late WN stars in M33 by Smith et al. (1997) and Crowther et al. (1997). Bianchi et al. (1994) have published UV spectroscopy of OB-type supergiants in M31 and M33, while Monteverd ...
WG4: Nuclear Astrophysics
... The Life Cycle of Matter Cosmic gas is collected by gravitational attraction into higher density regions, to eventually form stars of different masses. These stars are stabilised against further gravitational concentration by the release of nuclear binding energy in their interiors. Depending on the ...
... The Life Cycle of Matter Cosmic gas is collected by gravitational attraction into higher density regions, to eventually form stars of different masses. These stars are stabilised against further gravitational concentration by the release of nuclear binding energy in their interiors. Depending on the ...
RXTE PCA Contributions to Monitoring Fast Transients
... Characteristics of the Transients Recurrence times of the transient outbursts range upward from 1/2 year. Duration of outburst is (roughly) correlated with peak luminosity in the same object and probably from object to object. Caveats: Rapid Burster and GRS 1747-312: similar durations, different lu ...
... Characteristics of the Transients Recurrence times of the transient outbursts range upward from 1/2 year. Duration of outburst is (roughly) correlated with peak luminosity in the same object and probably from object to object. Caveats: Rapid Burster and GRS 1747-312: similar durations, different lu ...
12C13C1414N21312C/13C3he43He/4He Sub-surface
... FeCZ (Eq. III) in the HR diagram for the three different metallicities (see Fig. 9, and Sect. ??). This figure displays the three qualitative trends of the iron zone we have just ...
... FeCZ (Eq. III) in the HR diagram for the three different metallicities (see Fig. 9, and Sect. ??). This figure displays the three qualitative trends of the iron zone we have just ...
from z=0 to z=1
... significantly higher SFR, higher attenuation, higher stellar mass, and higher correlation length than LBGs. 7. At intermediate redshifts of z~0.6, UV selected galaxies show moderate evolution in stellar mass in the sense that for a given luminosity, galaxies at z=0.6 have stellar mass ~2 times less ...
... significantly higher SFR, higher attenuation, higher stellar mass, and higher correlation length than LBGs. 7. At intermediate redshifts of z~0.6, UV selected galaxies show moderate evolution in stellar mass in the sense that for a given luminosity, galaxies at z=0.6 have stellar mass ~2 times less ...
Cataclysmic Cosmic Events and How to Observe Them www.springer.com/series/5338
... those telescopes took hours to reach such limits, and then the photographic plates had to be developed, fixed, and examined by eye. In the modern era digital images can be obtained in minutes and analyzed ‘on the fly’ while more images are being downloaded. Developments can be e-mailed to other inte ...
... those telescopes took hours to reach such limits, and then the photographic plates had to be developed, fixed, and examined by eye. In the modern era digital images can be obtained in minutes and analyzed ‘on the fly’ while more images are being downloaded. Developments can be e-mailed to other inte ...
Observational studies of stellar rotation
... The oldest method used to measure stellar rotation consists in monitoring the visibility of magnetic spots on the stellar surface. In the Western world, Galileo Galilei was amongst the first observers of the early 17th century to provide an estimate of the Sun’s rotational period by observing the su ...
... The oldest method used to measure stellar rotation consists in monitoring the visibility of magnetic spots on the stellar surface. In the Western world, Galileo Galilei was amongst the first observers of the early 17th century to provide an estimate of the Sun’s rotational period by observing the su ...
NSDL_WS_1_Astonomy
... Astronomy is a dynamic science. New discoveries add to our knowledge of the universe and our own solar system. • New images brought to use by the Hubble Space Telescope show that star formation is more complex and violent than anyone had believed. • Supersonic jets of particles and dense clots of d ...
... Astronomy is a dynamic science. New discoveries add to our knowledge of the universe and our own solar system. • New images brought to use by the Hubble Space Telescope show that star formation is more complex and violent than anyone had believed. • Supersonic jets of particles and dense clots of d ...
ESA BR-170 - ESA Science
... s recently as 200 years ago the Earth was widely thought to be only about six thousand years old – in 1650 Bishop Ussher had famously calculated the date of creation as 4004 BC. The first to recognise the true age of the Earth was a Scottish physician called James Hutton, an amateur geologist, who, ...
... s recently as 200 years ago the Earth was widely thought to be only about six thousand years old – in 1650 Bishop Ussher had famously calculated the date of creation as 4004 BC. The first to recognise the true age of the Earth was a Scottish physician called James Hutton, an amateur geologist, who, ...
The Jansky Very Large Array – New Capabilities, New Science
... observations as well as VLA. • The rise of ALMA will strengthen this complementarity, with stellar scientific results. • New example – Wagg and Carilli combine VLA and ALMA for early forming galaxies: – Massive galaxies at z~2 must have formed at earlier epochs. – Formation phase seems to have been ...
... observations as well as VLA. • The rise of ALMA will strengthen this complementarity, with stellar scientific results. • New example – Wagg and Carilli combine VLA and ALMA for early forming galaxies: – Massive galaxies at z~2 must have formed at earlier epochs. – Formation phase seems to have been ...
Phases of Stellar Evolution
... For the pp cycle at 4(106) < T < 2.4(107) K 6 n 3.5 in ε= ε0ρTn This means that the temperature gradient is much smaller. There is less centralization in the energy generation and little tendency for convection in the core. pp cores are radiative ...
... For the pp cycle at 4(106) < T < 2.4(107) K 6 n 3.5 in ε= ε0ρTn This means that the temperature gradient is much smaller. There is less centralization in the energy generation and little tendency for convection in the core. pp cores are radiative ...
Eye in the sky - Academy of Science of South Africa
... astronomical sciences have had access to the SALT. During those five years SALT has steadily produced good quality data for both South African and international users – a true example of global collaboration in science. SALT is the largest single optical telescope in the southern hemisphere and amon ...
... astronomical sciences have had access to the SALT. During those five years SALT has steadily produced good quality data for both South African and international users – a true example of global collaboration in science. SALT is the largest single optical telescope in the southern hemisphere and amon ...
Effects of triple-α and C(α, γ )16 O reaction rates on the supernova
... rates (εn ) become significantly larger than the neutrino energy loss rates (εν ). We can understand clearly that helium ignition under the degenerate condition (εn = εν ) occurs at considerably lower temperature and density points compared with the previous case [26]. The effects of the OKK rate on ...
... rates (εn ) become significantly larger than the neutrino energy loss rates (εν ). We can understand clearly that helium ignition under the degenerate condition (εn = εν ) occurs at considerably lower temperature and density points compared with the previous case [26]. The effects of the OKK rate on ...
Astrophysics Pristine CNO abundances from Magellanic Cloud B stars
... Large Magellanic Cloud (LMC). Apart from H ii regions, unevolved OB-type stars are currently the only accessible source of present-day CNO abundances for the MCs not altered by stellar evolution. Using UVES on the VLT, we obtained spectra of sufficient resolution (R = 20 000) and signal-to-noise (S/ ...
... Large Magellanic Cloud (LMC). Apart from H ii regions, unevolved OB-type stars are currently the only accessible source of present-day CNO abundances for the MCs not altered by stellar evolution. Using UVES on the VLT, we obtained spectra of sufficient resolution (R = 20 000) and signal-to-noise (S/ ...
Properties of Wolf-Rayet Stars - Paul Crowther, University of Sheffield
... Visual spectral classification of WR stars is based on emission line strengths and line ratios (Smith 1968). To date, high-ionization WN2 to WN5 are known as ‘early WN’ (WNE) stars, and low-ionization WN7 to WN9(–11) stars known as ‘late WN’ (WNL) stars, and WN6 stars either early or late-type. Comp ...
... Visual spectral classification of WR stars is based on emission line strengths and line ratios (Smith 1968). To date, high-ionization WN2 to WN5 are known as ‘early WN’ (WNE) stars, and low-ionization WN7 to WN9(–11) stars known as ‘late WN’ (WNL) stars, and WN6 stars either early or late-type. Comp ...
Chapter 10
... Where in the Galaxy are these types of stars located? 6. Describe the characteristics of and differences between open and globular clusters. 7. What is the observational evidence that something strange is happening in the nucleus of our Galaxy, and what is the probable explanation? CHAPTER 13 1. Wha ...
... Where in the Galaxy are these types of stars located? 6. Describe the characteristics of and differences between open and globular clusters. 7. What is the observational evidence that something strange is happening in the nucleus of our Galaxy, and what is the probable explanation? CHAPTER 13 1. Wha ...
Chemical abundances and winds of massive stars in M31: a Btype
... their M31 target stars prevented strong constraints being placed on the exact shape of this extinction curve. We have briefly reinvestigated this issue using a slightly different procedure, following Fitzpatrick (1986) in using other B-type supergiants in the LMC as the comparison stars. We chose Sk ...
... their M31 target stars prevented strong constraints being placed on the exact shape of this extinction curve. We have briefly reinvestigated this issue using a slightly different procedure, following Fitzpatrick (1986) in using other B-type supergiants in the LMC as the comparison stars. We chose Sk ...
1. INTRODUCTION
... as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do not display rotationally modulated light curves and that can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only o ...
... as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do not display rotationally modulated light curves and that can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only o ...
Hubble Space Telescope Imaging of Post
... these systems are clearly merging with their companions. Highly disturbed objects have greater host luminosities. Compared to other AGN of similar luminosity and redshift these PSQs have a higher fraction of early-type host and visible disturbances. Our most luminous objects with disturbed early-typ ...
... these systems are clearly merging with their companions. Highly disturbed objects have greater host luminosities. Compared to other AGN of similar luminosity and redshift these PSQs have a higher fraction of early-type host and visible disturbances. Our most luminous objects with disturbed early-typ ...
The cosmic origin of fluorine and sulphur
... Popular summary in English Practically only the two lightest elements, hydrogen and helium, were formed during the Big Bang when our Universe was born. All other elements have been formed, and keep being formed, in different processes in different types of stars. is means that all atoms, except hydro ...
... Popular summary in English Practically only the two lightest elements, hydrogen and helium, were formed during the Big Bang when our Universe was born. All other elements have been formed, and keep being formed, in different processes in different types of stars. is means that all atoms, except hydro ...
Newtonian world and astrophysics 5.1 Thermal physics
... hot liquid to molecules of the colder liquid. The temperature of the hot liquid decreases and the temperature of the cold liquid increases. Thermal equilibrium is reached when there is no net energy transfer between the molecules of the two liquids – both liquids are at the same temperature. Values ...
... hot liquid to molecules of the colder liquid. The temperature of the hot liquid decreases and the temperature of the cold liquid increases. Thermal equilibrium is reached when there is no net energy transfer between the molecules of the two liquids – both liquids are at the same temperature. Values ...