Link
... 1994). The Sun appears to be well inside this expanding ring. The nearest OB associations, such as Sco-Cen (d ≈ 150 pc), Per OB2 (d ≈ 300 pc), Orion OB1 (d ≈ 400), and Lac OB1b (d ≈ 500 pc), and the B and A stars that trace the so-called ‘Gould’s Belt’ of nearby young and intermediate age stars are ...
... 1994). The Sun appears to be well inside this expanding ring. The nearest OB associations, such as Sco-Cen (d ≈ 150 pc), Per OB2 (d ≈ 300 pc), Orion OB1 (d ≈ 400), and Lac OB1b (d ≈ 500 pc), and the B and A stars that trace the so-called ‘Gould’s Belt’ of nearby young and intermediate age stars are ...
evolución química de la nube grande de magallanes.
... previous studies. And for the first time for SL869, a metallicity of [FeI/H]= −0.47 (σint = 0.04). In addition, an age of 1.45 Gyr (σ = 0.2Gyr) was estimated for SL869 using isochrone fitting. One of the most important results in this study is that from the mean [α/Fe] vs [Fe/H] plot (Fig. 3.7). We ...
... previous studies. And for the first time for SL869, a metallicity of [FeI/H]= −0.47 (σint = 0.04). In addition, an age of 1.45 Gyr (σ = 0.2Gyr) was estimated for SL869 using isochrone fitting. One of the most important results in this study is that from the mean [α/Fe] vs [Fe/H] plot (Fig. 3.7). We ...
Post Common Envelope Binaries from SDSS. I: 101 white dwarf
... and Eisenstein et al. (2006), as well as a set of WDMS independently found in the SDSS data by our team. This search resulted in a sample of 130 WDMS with two to seven SDSS spectra. Among those WDMS, 101 systems have a clearly pronounced Na I λλ 8183.27,8194.81 absorption doublet and/or Hα emission ...
... and Eisenstein et al. (2006), as well as a set of WDMS independently found in the SDSS data by our team. This search resulted in a sample of 130 WDMS with two to seven SDSS spectra. Among those WDMS, 101 systems have a clearly pronounced Na I λλ 8183.27,8194.81 absorption doublet and/or Hα emission ...
Dust input from AGB stars in the Large Magellanic Cloud
... stars evolving up to the red giant branch lose mass via stellar winds, the properties of stellar wind at this stage prohibit efficient dust growth (Gail et al. 2009). The transition to a highly supersonic outflow occurs rather close to the star where temperatures are too high for dust formation. In ...
... stars evolving up to the red giant branch lose mass via stellar winds, the properties of stellar wind at this stage prohibit efficient dust growth (Gail et al. 2009). The transition to a highly supersonic outflow occurs rather close to the star where temperatures are too high for dust formation. In ...
Evolutionary and pulsational properties of white dwarf stars
... wide variety of stellar populations. In fact, accurate knowledge of the rate at which white dwarfs cool constitutes a fundamental issue and provides an independent cosmic clock to constrain the age and previous history of the Galactic populations including the disk (Winget et al. 1987; García-Berro ...
... wide variety of stellar populations. In fact, accurate knowledge of the rate at which white dwarfs cool constitutes a fundamental issue and provides an independent cosmic clock to constrain the age and previous history of the Galactic populations including the disk (Winget et al. 1987; García-Berro ...
Models of the Structure and Evolution of Protoplanetary Disks
... regions of the disk beyond the dust sublimation radius, i.e. beyond 0.1 - 1 AU, depending on the stellar luminosity. We will be mostly concerned with models that aim to fit spectra of the dust continuum or gas lines, and derive physical parameters from these fits. For optically thick disks, these pa ...
... regions of the disk beyond the dust sublimation radius, i.e. beyond 0.1 - 1 AU, depending on the stellar luminosity. We will be mostly concerned with models that aim to fit spectra of the dust continuum or gas lines, and derive physical parameters from these fits. For optically thick disks, these pa ...
Global structure and kinematics of stellar haloes in cosmological
... (Ferland et al. 1998) that contain cooling rates as a function of density, temperature, and redshift and that account for the presence of the cosmic microwave background and photoionisation from a Haardt & Madau (2001) ionising UV/X-Ray background (see Wiersma et al. 2009a). This background is switc ...
... (Ferland et al. 1998) that contain cooling rates as a function of density, temperature, and redshift and that account for the presence of the cosmic microwave background and photoionisation from a Haardt & Madau (2001) ionising UV/X-Ray background (see Wiersma et al. 2009a). This background is switc ...
Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian
... sequence objects8 he suggested to be rotationally unstable stars, namely to be “lens shaped bodies, which eject matter at the equator, thus forming a nebulous ring which revolves around the star and gives rise to emission lines.” This also brought the unification of shell stars with Be stars. Shell ...
... sequence objects8 he suggested to be rotationally unstable stars, namely to be “lens shaped bodies, which eject matter at the equator, thus forming a nebulous ring which revolves around the star and gives rise to emission lines.” This also brought the unification of shell stars with Be stars. Shell ...
Modelling the observed properties of carbon-enhanced metal
... wind mass transfer in the past from a more massive thermally-pulsing asymptotic giant branch (AGB) primary star in a binary system. In this work we generate synthetic populations of binary stars at metallicity Z = 0.0001 ([Fe/H] ≈ −2.3), with the aim of reproducing the observed fraction of CEMP star ...
... wind mass transfer in the past from a more massive thermally-pulsing asymptotic giant branch (AGB) primary star in a binary system. In this work we generate synthetic populations of binary stars at metallicity Z = 0.0001 ([Fe/H] ≈ −2.3), with the aim of reproducing the observed fraction of CEMP star ...
astro-ph/9808039 PDF
... the optical fluxes reported in Paper I were a factor of 1.7 too high, because an incorrect aperture diameter was applied to the Hii region HK11 (Kennicutt 1988), whose Hα flux was the calibration standard. The corrected calibration of the GAFPIC data has been confirmed by comparison to another study ...
... the optical fluxes reported in Paper I were a factor of 1.7 too high, because an incorrect aperture diameter was applied to the Hii region HK11 (Kennicutt 1988), whose Hα flux was the calibration standard. The corrected calibration of the GAFPIC data has been confirmed by comparison to another study ...
Asteroseismic Modelling of Solar-like Stars
... through nuclear fusion and emit it in the form of light. Furthermore, most of the elements that the Earth and all the living things are made up of have been produced in the stars. Scientists are in particular interested in understanding what is beyond apparent. However, all the information we have a ...
... through nuclear fusion and emit it in the form of light. Furthermore, most of the elements that the Earth and all the living things are made up of have been produced in the stars. Scientists are in particular interested in understanding what is beyond apparent. However, all the information we have a ...
3D LTE spectral line formation with scattering in red giant stars
... enhancement of α-elements for the most metal-poor model. The simulations were created with the StaggerCode (Nordlund & Galsgaard 1995), which solves the coupled equations of compressible hydrodynamics and time-independent radiative transfer, computing radiative heating rates in LTE. Lineblanketing i ...
... enhancement of α-elements for the most metal-poor model. The simulations were created with the StaggerCode (Nordlund & Galsgaard 1995), which solves the coupled equations of compressible hydrodynamics and time-independent radiative transfer, computing radiative heating rates in LTE. Lineblanketing i ...
The Properties of Super Star Clusters in A Sample of
... would do things like spontaneously bring me dinner when I didn’t have time to go home myself. He also kept me from completely burying myself in work by coaxing me out for hikes in the mountains. Along with my classmates, Marc DeRosa (DeRosa) and Marc Swisdak (Swisdak) were a fundamental part of my s ...
... would do things like spontaneously bring me dinner when I didn’t have time to go home myself. He also kept me from completely burying myself in work by coaxing me out for hikes in the mountains. Along with my classmates, Marc DeRosa (DeRosa) and Marc Swisdak (Swisdak) were a fundamental part of my s ...
Submm Observations of Massive Star Formation in the Giant
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
Luminous Blue Variables are Antisocial: Their Isolation Implies that
... Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter wer ...
... Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter wer ...
Stellar Mass Loss in Globular - Jodrell Bank Centre for Astrophysics
... transition between the two driving regimes as being at earlier spectral types than in solar-metallicity stars, suggesting that pulsation and continuum-driving become the dominant wind drivers at around K5∼M3, or ∼1500 L⊙ . Even at low metallicity, ...
... transition between the two driving regimes as being at earlier spectral types than in solar-metallicity stars, suggesting that pulsation and continuum-driving become the dominant wind drivers at around K5∼M3, or ∼1500 L⊙ . Even at low metallicity, ...
The binary fractions in the massive young Large Magellanic Cloud
... analysis method with respect to that employed in de Grijs et al. (2013). We also take the possible effects of fast stellar rotation into consideration and show that the results remain robust, even if rapidly rotating stars were to contribute significantly to the clusters’ CMDs. We discuss the detail ...
... analysis method with respect to that employed in de Grijs et al. (2013). We also take the possible effects of fast stellar rotation into consideration and show that the results remain robust, even if rapidly rotating stars were to contribute significantly to the clusters’ CMDs. We discuss the detail ...
Formation of low-mass helium white dwarfs
... main sequence which is the region in the HRD where stars spend most of their lives and, therefore, is also the most populated region of the diagram. At the end of this phase7 , the star will have an inert helium core surrounded by a hydrogen envelope. A low-mass star, such as our own Sun, will spend ...
... main sequence which is the region in the HRD where stars spend most of their lives and, therefore, is also the most populated region of the diagram. At the end of this phase7 , the star will have an inert helium core surrounded by a hydrogen envelope. A low-mass star, such as our own Sun, will spend ...
The Dynamics of White Dwarfs, Black Holes and Stellar Cusps
... mass white dwarfs have low velocity dispersion. This is the result of less scattering during the shorter lifetime of their more massive precursors. The kinematics of the highest-mass white dwarfs (> 0.95 M⊙) are also investigated, and it is shown that they are consistent with the majority being form ...
... mass white dwarfs have low velocity dispersion. This is the result of less scattering during the shorter lifetime of their more massive precursors. The kinematics of the highest-mass white dwarfs (> 0.95 M⊙) are also investigated, and it is shown that they are consistent with the majority being form ...
Stellar activity in exoplanet hosts Enrique Herrero Casas
... Most of the efforts on the search and characterization of Earth-like exoplanets are currently focused on low mass stars. These represent the vast majority of the population in our galaxy (about 75% of the stars have a lower mass than the Sun) and their interest lies in the fact that the photometric a ...
... Most of the efforts on the search and characterization of Earth-like exoplanets are currently focused on low mass stars. These represent the vast majority of the population in our galaxy (about 75% of the stars have a lower mass than the Sun) and their interest lies in the fact that the photometric a ...
Systematic variation in the apparent burning area of thermonuclear
... peak inferred bolometric flux, f bol,max . We end our analysis at the time tstop that the inferred bolometric flux drops below a fixed fraction of f bol,max . Experiments indicated that the precise value of this fraction does not change the results appreciably, hence we present values for a fraction ...
... peak inferred bolometric flux, f bol,max . We end our analysis at the time tstop that the inferred bolometric flux drops below a fixed fraction of f bol,max . Experiments indicated that the precise value of this fraction does not change the results appreciably, hence we present values for a fraction ...
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 ...
H 2 O, OH, SiO, NH 3 and CH 3 OH
... [proh-toh-stahr] an early stage in the evolution of a star, after the beginning of the collapse of the gas cloud from which it is formed, but before sufficient contraction has occurred to permit initiation of nuclear reactions at its core. ...
... [proh-toh-stahr] an early stage in the evolution of a star, after the beginning of the collapse of the gas cloud from which it is formed, but before sufficient contraction has occurred to permit initiation of nuclear reactions at its core. ...
An extended main-sequence turn-off in the Small
... metals. With this choice, the position of the MS (for F475W 22 mag) is determined by two parameters only: the absolute distance modulus (m − M)0 , which just shifts the isochrones vertically in the plot, and the total extinction AV , which moves the isochrones along the extinction/reddening vector ...
... metals. With this choice, the position of the MS (for F475W 22 mag) is determined by two parameters only: the absolute distance modulus (m − M)0 , which just shifts the isochrones vertically in the plot, and the total extinction AV , which moves the isochrones along the extinction/reddening vector ...