mass transfer in close, rapidly accreting protobinaries
... 102 M yr1 from luminous embedded protostars (Henning et al. 2000) also suggest high accretion rates. The combination of rapid accretion and high mass produces protostars with very large radii, for two reasons. First, Stahler (1988) shows that prior to the onset of deuterium burning, the radius o ...
... 102 M yr1 from luminous embedded protostars (Henning et al. 2000) also suggest high accretion rates. The combination of rapid accretion and high mass produces protostars with very large radii, for two reasons. First, Stahler (1988) shows that prior to the onset of deuterium burning, the radius o ...
arXiv:astro-ph/0701792v1 29 Jan 2007
... The motivation of this paper is to link several physical phenomena mentioned above, and explain them coherently. In this paper, we will present a simple analytical model to describe the star formation during the formation of the spheroidal component and the possible connection between the central st ...
... The motivation of this paper is to link several physical phenomena mentioned above, and explain them coherently. In this paper, we will present a simple analytical model to describe the star formation during the formation of the spheroidal component and the possible connection between the central st ...
Text Collection
... Neil and Buzz stay on the moon for 21 hours and 36 minutes, but only a little more than 2 hours of that time is spent outside the lunar module. They perform three minor experiments and load two aluminum suitcases with 48 pounds (22 kilograms) of moon dust and rocks. The three minor experiments: To ...
... Neil and Buzz stay on the moon for 21 hours and 36 minutes, but only a little more than 2 hours of that time is spent outside the lunar module. They perform three minor experiments and load two aluminum suitcases with 48 pounds (22 kilograms) of moon dust and rocks. The three minor experiments: To ...
A double detached shell around a post
... become large and cool red supergiants. When they leave the red supergiant branch, those stars evolve in the yellow hypergiant phase, followed by the luminous blue variable (LBV) phase, to finally become Wolf-Rayet stars (Oudmaijer et al. 2009). The stellar winds associated with these phases, followe ...
... become large and cool red supergiants. When they leave the red supergiant branch, those stars evolve in the yellow hypergiant phase, followed by the luminous blue variable (LBV) phase, to finally become Wolf-Rayet stars (Oudmaijer et al. 2009). The stellar winds associated with these phases, followe ...
Chapter 8
... appropriate for its mass, with a radius roughly given by eq. (8.4). From this moment on we speak of the pre-main sequence phase of evolution. The pre-main sequence (PMS) star radiates at a luminosity determined by its radius on the Hayashi line. Since it is still too cool for nuclear burning, the en ...
... appropriate for its mass, with a radius roughly given by eq. (8.4). From this moment on we speak of the pre-main sequence phase of evolution. The pre-main sequence (PMS) star radiates at a luminosity determined by its radius on the Hayashi line. Since it is still too cool for nuclear burning, the en ...
Acta Polytechnica
... two-temperature thermal models. Since the merging clusters can often have shock-heated, super-hot (kT ∼ 20 keV) gas, and its contribution is not negligible in the interpretation of the hard X-ray origin, it is essential to determine the thermal component with high accuracy. This motivated us to carr ...
... two-temperature thermal models. Since the merging clusters can often have shock-heated, super-hot (kT ∼ 20 keV) gas, and its contribution is not negligible in the interpretation of the hard X-ray origin, it is essential to determine the thermal component with high accuracy. This motivated us to carr ...
on the rotational dynamics of magnetically threaded disks around
... vertically disrupted and viscously unstable disk solution inside a critical radius. They also argued that the viscous instability associated with the elevated temperature in the inner-disk regions is due to magnetically enhanced viscous dissipation, which causes the vertical equilibrium to break dow ...
... vertically disrupted and viscously unstable disk solution inside a critical radius. They also argued that the viscous instability associated with the elevated temperature in the inner-disk regions is due to magnetically enhanced viscous dissipation, which causes the vertical equilibrium to break dow ...
Chapter 6 The kinematics of NGC1333
... An open question in the subject of low-mass star formation is how and when the velocity field of the molecular gas in the protostellar envelope changes from being dominated by radial infall to being dominated by Keplerian rotation. It is well known that in the early stages of star formation, gas fal ...
... An open question in the subject of low-mass star formation is how and when the velocity field of the molecular gas in the protostellar envelope changes from being dominated by radial infall to being dominated by Keplerian rotation. It is well known that in the early stages of star formation, gas fal ...
Extreme Physics Explorer - High Energy Astrophysics
... If the field is strong enough polarization is altered by gravitational effects. The polarization plane rotates continuously with energy because of General Relativistic effects. This is a signature of the presence of a black-hole Stark & Connors, Connors& Stark, 1977, Connors, Piran & Stark, 1980. ...
... If the field is strong enough polarization is altered by gravitational effects. The polarization plane rotates continuously with energy because of General Relativistic effects. This is a signature of the presence of a black-hole Stark & Connors, Connors& Stark, 1977, Connors, Piran & Stark, 1980. ...
Astronomy, Astrophysics, and Cosmology
... Luis A. Anchordoqui Department of Physics and Astronomy Lehman College, City University of New York ...
... Luis A. Anchordoqui Department of Physics and Astronomy Lehman College, City University of New York ...
Expanding the Catalog: Considering the Importance
... Stars with longer MS lifetimes than would normally be expected (e.g. for the three 0.8 M carbon models at 1.5 Z , which do exhibit the inverted MS lifetimes) are actually also brighter than usual, likely because they have access to more fuel from outer layers of the star that are brought down into ...
... Stars with longer MS lifetimes than would normally be expected (e.g. for the three 0.8 M carbon models at 1.5 Z , which do exhibit the inverted MS lifetimes) are actually also brighter than usual, likely because they have access to more fuel from outer layers of the star that are brought down into ...
Analysis of white dwarfs with strange-matter cores
... for 10 white dwarfs in visual binaries or common proper-motion systems as well as 11 field white dwarfs. Complementary HST observations have also been made, for example to better determine the spectroscopy for Procyon B [25] and the pulsation of G226-29 [19]. Procyon B at first appeared as a compact ...
... for 10 white dwarfs in visual binaries or common proper-motion systems as well as 11 field white dwarfs. Complementary HST observations have also been made, for example to better determine the spectroscopy for Procyon B [25] and the pulsation of G226-29 [19]. Procyon B at first appeared as a compact ...
pdf-file - Max-Planck-Institut für Astronomie
... radiation pressure. Thus, the star formation scenario for low- and high-mass stars could in principle be the same (e.g., Keto 2007), suggesting that high-mass star formation could be a scaled-up version of the low-mass star formation process. In this paper, we aim to construct a global model (with t ...
... radiation pressure. Thus, the star formation scenario for low- and high-mass stars could in principle be the same (e.g., Keto 2007), suggesting that high-mass star formation could be a scaled-up version of the low-mass star formation process. In this paper, we aim to construct a global model (with t ...
Order of Magnitude Icebreaker
... Order of magnitude estimates Ideas to bring home ★ Multiple pathways, depending on available information ★ Good illustration of what research is about ★ Do not hesitate to simplify as much as possible ★ Rescale to situations you are familiar with ★ Basic physics can give good insight on many proble ...
... Order of magnitude estimates Ideas to bring home ★ Multiple pathways, depending on available information ★ Good illustration of what research is about ★ Do not hesitate to simplify as much as possible ★ Rescale to situations you are familiar with ★ Basic physics can give good insight on many proble ...
McConnell XGPolarimetry SSE
... The most vivid polarization signatures are a strong energy dependence of the Stokes parameters and a 90°-position-angle jump at an energy-dependent phase, occurring where the normal-mode propagation through the so-called “vacuum resonance” [18] changes from adiabatic to nonadiabatic [19]. Detection ...
... The most vivid polarization signatures are a strong energy dependence of the Stokes parameters and a 90°-position-angle jump at an energy-dependent phase, occurring where the normal-mode propagation through the so-called “vacuum resonance” [18] changes from adiabatic to nonadiabatic [19]. Detection ...
Publications 2003 - Département d`Astrophysique, Géophysique et
... the Scuti star XX Pyx. Applying a cross-correlation technique to the spectra, we found clear radialvelocity variations with a large amplitude. We derive the orbital parameters and confirm an orbital period of 1.15d, as suggested previously on the basis of photometric variations. The amplitude of the ...
... the Scuti star XX Pyx. Applying a cross-correlation technique to the spectra, we found clear radialvelocity variations with a large amplitude. We derive the orbital parameters and confirm an orbital period of 1.15d, as suggested previously on the basis of photometric variations. The amplitude of the ...
Galactic sources science with AGILE The case of the Carina Region
... nebular structures. An extremely peculiar system in the region and one of the most interesting objects of our Galaxy is the Z Carinae binary [5,6], where the primary star is a massive ( 100 solar masses) luminous blue variable (LBV) star orbiting in a very eccentric binary ðe 0:9Þ with a compani ...
... nebular structures. An extremely peculiar system in the region and one of the most interesting objects of our Galaxy is the Z Carinae binary [5,6], where the primary star is a massive ( 100 solar masses) luminous blue variable (LBV) star orbiting in a very eccentric binary ðe 0:9Þ with a compani ...
Observations of binary systems with pulsating components
... • Spectroscopic binaries: stars which exhibit periodic displacement of their spectral lines owing to Doppler effect caused by orbital motion. • Depending on components’ relative brightness, the observed spectrum will show the displacement of lines of one or both components (if a star is too faint, i ...
... • Spectroscopic binaries: stars which exhibit periodic displacement of their spectral lines owing to Doppler effect caused by orbital motion. • Depending on components’ relative brightness, the observed spectrum will show the displacement of lines of one or both components (if a star is too faint, i ...
Evolution of the Highest Redshift Quasars
... – How closely tied are the earliest SBHs and galaxies? Or are we just picking up early starters in term of BH accretion in the most luminous quasars? ...
... – How closely tied are the earliest SBHs and galaxies? Or are we just picking up early starters in term of BH accretion in the most luminous quasars? ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.