LSS-GAC – A LAMOST Spectroscopic Survey of the Galactic Anti
... Modern large scale surveys, represented by the extremely successful SDSS (York et al. 2000), have revolutionized our understanding of galaxy formation and evolution, including the still on-going assemblage process of the Milky Way. On the other hand, being primarily an extragalactic program, the vol ...
... Modern large scale surveys, represented by the extremely successful SDSS (York et al. 2000), have revolutionized our understanding of galaxy formation and evolution, including the still on-going assemblage process of the Milky Way. On the other hand, being primarily an extragalactic program, the vol ...
LSS-GAC – A LAMOST Spectroscopic Survey of the
... Modern large scale surveys, represented by the extremely successful SDSS (York et al. 2000), have revolutionized our understanding of galaxy formation and evolution, including the still on-going assemblage process of the Milky Way. On the other hand, being primarily an extragalactic program, the vol ...
... Modern large scale surveys, represented by the extremely successful SDSS (York et al. 2000), have revolutionized our understanding of galaxy formation and evolution, including the still on-going assemblage process of the Milky Way. On the other hand, being primarily an extragalactic program, the vol ...
White Dwarf Stars
... force of gas pressure provided by high temperatures inside the star. Although energy is lost by radiation, the star maintains its high temperature through nuclear fusion as it burns hydrogen into helium. These two forces balance each other precisely, creating a stable stellar structure—at least for ...
... force of gas pressure provided by high temperatures inside the star. Although energy is lost by radiation, the star maintains its high temperature through nuclear fusion as it burns hydrogen into helium. These two forces balance each other precisely, creating a stable stellar structure—at least for ...
The Carina Dwarf Spheroidal Galaxy: A Goldmine for Cosmology
... 151 stars. Expressed as a standard devi ation, the average standard residual of one star is 0.027, 0.017, 0.012, 0.012 and 0.016 mag in U, B, V, R and I. It does not seem that these numbers can be reduced by obtaining more observations; rather, they represent a fundamental limit to the reliability ...
... 151 stars. Expressed as a standard devi ation, the average standard residual of one star is 0.027, 0.017, 0.012, 0.012 and 0.016 mag in U, B, V, R and I. It does not seem that these numbers can be reduced by obtaining more observations; rather, they represent a fundamental limit to the reliability ...
Post-AGB stars in the Magellanic Clouds and neutron
... updated to those calculated by Lederer & Aringer (2009). Mass loss was included using the formula of Reimers (1975) during the RGB phase (with η = 0.4) and the formula of Vassiliadis & Wood (1993) during the AGB phase. Instantaneous mixing was used in convective zones, and the convective boundaries ...
... updated to those calculated by Lederer & Aringer (2009). Mass loss was included using the formula of Reimers (1975) during the RGB phase (with η = 0.4) and the formula of Vassiliadis & Wood (1993) during the AGB phase. Instantaneous mixing was used in convective zones, and the convective boundaries ...
1. INTRODUCTION 2. THE MODEL
... A standard model of such a protoplanetary disk is that of a steady state disk in vertical hydrostatic equilibrium, with gas and dust fully mixed and thermally coupled (Kenyon & Hartmann 1987). Such a disk is Ñared, not Ñat, but still geometrically thin in the sense deÐned by Pringle (1981). The disk ...
... A standard model of such a protoplanetary disk is that of a steady state disk in vertical hydrostatic equilibrium, with gas and dust fully mixed and thermally coupled (Kenyon & Hartmann 1987). Such a disk is Ñared, not Ñat, but still geometrically thin in the sense deÐned by Pringle (1981). The disk ...
– 1 – 1. Discrete Spectral Lines – DRAFT, INCOMPLETE
... Macroturbulence arises from large scale motions such as convection or rotation. (vrot for the Sun is about 1.9 km/sec.) In this case the local value of the line absorption α(ν) and of the predicted I(ν) is unaffected, but the velocity shifts this entire profile in frequency across the disk of the st ...
... Macroturbulence arises from large scale motions such as convection or rotation. (vrot for the Sun is about 1.9 km/sec.) In this case the local value of the line absorption α(ν) and of the predicted I(ν) is unaffected, but the velocity shifts this entire profile in frequency across the disk of the st ...
SHELL BURNING STARS: Red Giants and Red Supergiants
... sequence. In that case the unstable models were separated from stable models by a turning point corresponding to a minimum in total stellar mass. In the helium flash case the unstable and stable models are separated by a turning point corresponding to a maximum of a degenerate helium core mass. Heli ...
... sequence. In that case the unstable models were separated from stable models by a turning point corresponding to a minimum in total stellar mass. In the helium flash case the unstable and stable models are separated by a turning point corresponding to a maximum of a degenerate helium core mass. Heli ...
This is the Title - Astronomy at Swarthmore College
... The circumstellar chemistry of asymptotic giant branch (AGB) stars is particularly interesting. Asymptotic giant branch stars are chemically active due to their high metallicity, which fosters the creation of complex molecules. Giants are at a point in their evolutionary track where they have burnt ...
... The circumstellar chemistry of asymptotic giant branch (AGB) stars is particularly interesting. Asymptotic giant branch stars are chemically active due to their high metallicity, which fosters the creation of complex molecules. Giants are at a point in their evolutionary track where they have burnt ...
jbrown_keck - Astronomy at Swarthmore College
... The circumstellar chemistry of asymptotic giant branch (AGB) stars is particularly interesting. Asymptotic giant branch stars are chemically active due to their high metallicity, which fosters the creation of complex molecules. Giants are at a point in their evolutionary track where they have burnt ...
... The circumstellar chemistry of asymptotic giant branch (AGB) stars is particularly interesting. Asymptotic giant branch stars are chemically active due to their high metallicity, which fosters the creation of complex molecules. Giants are at a point in their evolutionary track where they have burnt ...
Red Supergiants, Luminous Blue Variables and Wolf
... In this context the questions of which stars do become dust-enshrouded, at which stage, for how long, become critical to make correct prediction of the mass lost by stellar winds. One can also note a very interesting point deduced from the study by van Loon et al. (2005), that for dust-enshrouded ob ...
... In this context the questions of which stars do become dust-enshrouded, at which stage, for how long, become critical to make correct prediction of the mass lost by stellar winds. One can also note a very interesting point deduced from the study by van Loon et al. (2005), that for dust-enshrouded ob ...
Determining the Stellar Spin Axis Orientation
... the displacement caused by the instrumental profile from the one generated by the stellar rotation requires a special observing technique and additional instrument. We have developed a differential image rotator, a small instrument to be inserted between the telescope output and the slit, which spli ...
... the displacement caused by the instrumental profile from the one generated by the stellar rotation requires a special observing technique and additional instrument. We have developed a differential image rotator, a small instrument to be inserted between the telescope output and the slit, which spli ...
Orbital Period Modulation in Chromospherically
... c) Gravitational Radiation: For the systems which include massive or a collapsed companion gravitational radiation causes loss of angular momentum. In these systems the orbital period will decrease monotonically. d) Galactic Acceleration: The eclipsing binaries revolve around the center of the Galax ...
... c) Gravitational Radiation: For the systems which include massive or a collapsed companion gravitational radiation causes loss of angular momentum. In these systems the orbital period will decrease monotonically. d) Galactic Acceleration: The eclipsing binaries revolve around the center of the Galax ...
The Mass-loss Rate of Red Supergiant
... driven winds around AGB stars and RSGs. The spectral energy distribution of the source can be specified analytically as either Planckian or broken power-law. The DUSTY code is described in Ivezic, Nenkova & Elitzur,1999. ...
... driven winds around AGB stars and RSGs. The spectral energy distribution of the source can be specified analytically as either Planckian or broken power-law. The DUSTY code is described in Ivezic, Nenkova & Elitzur,1999. ...
Determining the Cepheid Period–Luminosity Relation Using
... effect is similar to the most recent one adopted by the Key Project group. This is a very reassuring result as our method is entirely independent from the methods that they have employed. In the case of the K-band, the effect is significantly (a factor of two) smaller and a null effect is consistent ...
... effect is similar to the most recent one adopted by the Key Project group. This is a very reassuring result as our method is entirely independent from the methods that they have employed. In the case of the K-band, the effect is significantly (a factor of two) smaller and a null effect is consistent ...
Collisions and close encounters involving massive main
... of the stars. The fits of the three-dimensional SPH models to the one-dimensional ATON model are clearly very good. Note that none of the 9 M models has a mass of exactly 9 M . The mass of the ATON model star is 8.85 M , of the high-resolution SPH model is 8.75 M and of the low-resolution model ...
... of the stars. The fits of the three-dimensional SPH models to the one-dimensional ATON model are clearly very good. Note that none of the 9 M models has a mass of exactly 9 M . The mass of the ATON model star is 8.85 M , of the high-resolution SPH model is 8.75 M and of the low-resolution model ...
Identifying Young far from Giant Stars Molecular Clouds
... It is speculated that classical T Tauri stars evolve into weak T Tauri stars, their accretion disks gradually dissipating over time (Walter et al. 1988). The two types of stars are similar in luminosities and effective temperature, implying a potential evolutionary relationship. The dust and gas wit ...
... It is speculated that classical T Tauri stars evolve into weak T Tauri stars, their accretion disks gradually dissipating over time (Walter et al. 1988). The two types of stars are similar in luminosities and effective temperature, implying a potential evolutionary relationship. The dust and gas wit ...
Winds from clusters with non-uniform stellar distribution
... 4038/4039), dwarf galaxies, classical starbursts, as well as in our galaxy amongst many other systems (for a review see Whitmore 2001). These star clusters can contain hundreds or thousands of very young, energetic stars, and have stellar densities far greater than those seen in normal OB associatio ...
... 4038/4039), dwarf galaxies, classical starbursts, as well as in our galaxy amongst many other systems (for a review see Whitmore 2001). These star clusters can contain hundreds or thousands of very young, energetic stars, and have stellar densities far greater than those seen in normal OB associatio ...
Astronomy Astrophysics MY Camelopardalis, a very massive merger progenitor &
... have assigned a number to each spectrum, sorted by date in ascending order. Heliocentric corrections, calculated using the rv program included in the Starlink suite, are also listed in Table 1. A total of 63 spectra were obtained, with fixed exposure times of 1800 s. The signal-to-noise ratio (S/N) ...
... have assigned a number to each spectrum, sorted by date in ascending order. Heliocentric corrections, calculated using the rv program included in the Starlink suite, are also listed in Table 1. A total of 63 spectra were obtained, with fixed exposure times of 1800 s. The signal-to-noise ratio (S/N) ...
Self-Regulation of Star Formation in Low Metallicity Clouds
... After metallicity becomes high enough (z/z⊙ > ∼ 10 ), effective star formation can start. Thus, the lower limit of metallicity of luminous objects is roughly estimated at z/z⊙ ∼ 10−2 . By the way, a SN release several ×M⊙ of heavy elements and the typical cloud mass (∼ ρrJ3 ) is ∼ 106 M⊙ . Thus, if ...
... After metallicity becomes high enough (z/z⊙ > ∼ 10 ), effective star formation can start. Thus, the lower limit of metallicity of luminous objects is roughly estimated at z/z⊙ ∼ 10−2 . By the way, a SN release several ×M⊙ of heavy elements and the typical cloud mass (∼ ρrJ3 ) is ∼ 106 M⊙ . Thus, if ...
The star-forming environment of an ultraluminous X-ray
... We applied the 4σ -detection source list to each filter image, and used PHOT and ALLSTARS to obtain instrumental magnitudes for the point sources in all three filters. Having to deal with a crowded field, we built a point spread function from the brightest, isolated stars and carried out profile-fit ...
... We applied the 4σ -detection source list to each filter image, and used PHOT and ALLSTARS to obtain instrumental magnitudes for the point sources in all three filters. Having to deal with a crowded field, we built a point spread function from the brightest, isolated stars and carried out profile-fit ...
Star Formation: Chemistry as a Probe of Embedded Protostars
... burst causes an increase in luminosity, which heats up the entire circumstellar envelope. The dust temperature responds particularly fast to a change in luminosity: < 100 s at 10 AU away from the star up to 5 × 106 s at a typical outer radius of 104 AU (Johnstone et al. 2013). The gas heats up more ...
... burst causes an increase in luminosity, which heats up the entire circumstellar envelope. The dust temperature responds particularly fast to a change in luminosity: < 100 s at 10 AU away from the star up to 5 × 106 s at a typical outer radius of 104 AU (Johnstone et al. 2013). The gas heats up more ...
Preliminary results of the Be stars proportion in LMC open
... disk and the emission, however it cannot explain alone the matter ejection and other mechanisms such as a combination with the beating of non radial pulsations is evoked (Porter & Rivinius 2003). In addition the low metallicity (Z) increases the rotational velocities of the OBBe stars, therefore the ...
... disk and the emission, however it cannot explain alone the matter ejection and other mechanisms such as a combination with the beating of non radial pulsations is evoked (Porter & Rivinius 2003). In addition the low metallicity (Z) increases the rotational velocities of the OBBe stars, therefore the ...
A model of low-mass neutron stars with a quark core
... state to the quark state with a transition parameter λ > 3/2 (λ = ρQ /(ρN + P0 /c2 )) in superdense nuclear matter. Our calculations of integrated parameters for superdense stars using this equation of state show that on the stable branch of the dependence of stellar mass on central pressure (dM/dPc ...
... state to the quark state with a transition parameter λ > 3/2 (λ = ρQ /(ρN + P0 /c2 )) in superdense nuclear matter. Our calculations of integrated parameters for superdense stars using this equation of state show that on the stable branch of the dependence of stellar mass on central pressure (dM/dPc ...