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... us call this the Clump Mass Function (ClMF). As already stated the story does not end here because when MCs are inspected in their large proportions or numbers, once again the number of MCs within a certain mass range are seen exhibiting a similar mass distribution as the IMF (Solomon et al. 1987; M ...
... us call this the Clump Mass Function (ClMF). As already stated the story does not end here because when MCs are inspected in their large proportions or numbers, once again the number of MCs within a certain mass range are seen exhibiting a similar mass distribution as the IMF (Solomon et al. 1987; M ...
Modelling the sulphur chemistry evolution in Orion KL
... Context. We present a study of the sulphur chemistry evolution in the region Orion KL along the gas and grain phases of the cloud. Aims. Our aim is to investigate the processes that dominate the sulphur chemistry in Orion KL and to determine how physical and chemical parameters, such as the final ma ...
... Context. We present a study of the sulphur chemistry evolution in the region Orion KL along the gas and grain phases of the cloud. Aims. Our aim is to investigate the processes that dominate the sulphur chemistry in Orion KL and to determine how physical and chemical parameters, such as the final ma ...
THE FINAL FATE OF STARS THAT IGNITE NEON AND OXYGEN
... evolutionary channel producing EC-SNe in addition to superAGB stars. These stars would be the most massive progenitors of EC-SNe and would ignite neon and oxygen burning offcenter where the maximum temperature has moved outward as neutrino emission produced a net cooling of the mildly electrondegene ...
... evolutionary channel producing EC-SNe in addition to superAGB stars. These stars would be the most massive progenitors of EC-SNe and would ignite neon and oxygen burning offcenter where the maximum temperature has moved outward as neutrino emission produced a net cooling of the mildly electrondegene ...
A Simple Model for r-Process Scatter and Halo Evolution
... Recent years have shown that halo stars indeed give unique insight into the r-process. With the advent of high dispersion, high S/N measurements, the abundance observations within and among halo stars has led to surprising new discoveries with important consequences for theories of the r-process as ...
... Recent years have shown that halo stars indeed give unique insight into the r-process. With the advent of high dispersion, high S/N measurements, the abundance observations within and among halo stars has led to surprising new discoveries with important consequences for theories of the r-process as ...
Compositions of Mercury`s earliest crust from magma ocean models
... The Mercury formation hypothesis presented here is motivated in part by the discovery of chondrites with an unusually high metallic iron composition: Bencubbinite (CB) chondrites. This rare primitive material contains at least 60 wt.% metallic iron (Weisberg et al., 2000). Should Mercury have been b ...
... The Mercury formation hypothesis presented here is motivated in part by the discovery of chondrites with an unusually high metallic iron composition: Bencubbinite (CB) chondrites. This rare primitive material contains at least 60 wt.% metallic iron (Weisberg et al., 2000). Should Mercury have been b ...
RADIO OBSERVATIONS RELATED TO STAR FORMATION P. G.
... which is four times the intrinsic flux density of Orion A.) Giant HII regions are known to define the main spiral structure in external galaxies. Georgelin and Georgelin (1976) used this fact to determine the spiral structure of our Galaxy on the basis of optical and radio observations of giant HII ...
... which is four times the intrinsic flux density of Orion A.) Giant HII regions are known to define the main spiral structure in external galaxies. Georgelin and Georgelin (1976) used this fact to determine the spiral structure of our Galaxy on the basis of optical and radio observations of giant HII ...
full text pdf
... and a cooler group that tends to have more modes, but stronger nonlinear effects and variable amplitudes. T h e hotter DAV stars tend to have only a few, short period modes, making seismology difficult for two reasons. First, without some way to constrain the mode identity of the observed pulsations ...
... and a cooler group that tends to have more modes, but stronger nonlinear effects and variable amplitudes. T h e hotter DAV stars tend to have only a few, short period modes, making seismology difficult for two reasons. First, without some way to constrain the mode identity of the observed pulsations ...
Tidal interaction of a rotating 1 vec {M_sun} star with a - UvA-DARE
... the unperturbed radiative energy flux, and where the other constants have their usual meaning. The factor η is a characteristic radiative diffusion length. Note that the radiative diffusion introduces a factor i, so that the tidal perturbations are complex-valued which expresses the induced phase-la ...
... the unperturbed radiative energy flux, and where the other constants have their usual meaning. The factor η is a characteristic radiative diffusion length. Note that the radiative diffusion introduces a factor i, so that the tidal perturbations are complex-valued which expresses the induced phase-la ...
The star formation history of galaxies in 3D: CALIFA perspective
... 2.1. Hubble sequence: stellar population properties of galaxies in the tuning-fork diagram One step to understand how galaxies form and evolve is classifying galaxies and studying their properties. Most of the massive galaxies in the near Universe are E, S0 and spirals (Blanton & Moustakas 2009), fo ...
... 2.1. Hubble sequence: stellar population properties of galaxies in the tuning-fork diagram One step to understand how galaxies form and evolve is classifying galaxies and studying their properties. Most of the massive galaxies in the near Universe are E, S0 and spirals (Blanton & Moustakas 2009), fo ...
astronomical oxygen isotopic evidence for supernova
... GCE over the past 4.6 billion years (the age of the solar system). A trend of decreasing [18 O]/[16 O] and [17 O]/[16 O] ratios at nearly constant [18 O]/[17 O] with increasing Galactocentric radius, RGC , was well established by early radio emission data (Wilson 1999), and the most recent data conf ...
... GCE over the past 4.6 billion years (the age of the solar system). A trend of decreasing [18 O]/[16 O] and [17 O]/[16 O] ratios at nearly constant [18 O]/[17 O] with increasing Galactocentric radius, RGC , was well established by early radio emission data (Wilson 1999), and the most recent data conf ...
The fundamental parameters of the roAp star γ Equulei
... optical design and equals about 170 nm in the medium spectral resolution. The red detector was centered on 750 nm on July 29 and on 640 nm on August 3 and 5. The blue detector was centered on 590 nm on July, 29 and on 470 nm on August 3 and 5. The bluer the wavelength, the more stringent the require ...
... optical design and equals about 170 nm in the medium spectral resolution. The red detector was centered on 750 nm on July 29 and on 640 nm on August 3 and 5. The blue detector was centered on 590 nm on July, 29 and on 470 nm on August 3 and 5. The bluer the wavelength, the more stringent the require ...
Exoplanetary Atmospheres
... the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formati ...
... the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formati ...
how dry is the brown dwarf desert? quantifying the
... production of a binary system but are usually recognized as distinct processes (e.g., Heacox 1999; Kroupa & Bouvier 2003; see, however, Boss 2002). The formation of companion brown dwarfs, with masses in between the stellar and planetary mass ranges, may have elements of both or some new mechanism ( ...
... production of a binary system but are usually recognized as distinct processes (e.g., Heacox 1999; Kroupa & Bouvier 2003; see, however, Boss 2002). The formation of companion brown dwarfs, with masses in between the stellar and planetary mass ranges, may have elements of both or some new mechanism ( ...
astro-ph/9505110 PDF
... Our results are shown in Figures 4 and 5 (Garnett et al. 1994, 1995). We nd that the C/O ratio increases monotonically as a function of O/H, from about 1/4 solar at the lowest metallicities up to solar values. At the same time, C/N also appears to increase with O/H in the irregular galaxies, but th ...
... Our results are shown in Figures 4 and 5 (Garnett et al. 1994, 1995). We nd that the C/O ratio increases monotonically as a function of O/H, from about 1/4 solar at the lowest metallicities up to solar values. At the same time, C/N also appears to increase with O/H in the irregular galaxies, but th ...
Binary star progenitors of long GRBs
... Fast rotating massive stars can evolve chemically homogeneous and become long GRBs Two classes of progenitors: single and binary stars In massive binaries it’s possible to spin up a star and obtain a collapsar This scenario is likely to produce a runaway WR which travel several hundred pc be ...
... Fast rotating massive stars can evolve chemically homogeneous and become long GRBs Two classes of progenitors: single and binary stars In massive binaries it’s possible to spin up a star and obtain a collapsar This scenario is likely to produce a runaway WR which travel several hundred pc be ...
Angular momentum and the formation of stars and
... magnetically dominated because the degree of ionization is high enough that the gas is strongly coupled to a magnetic field, and with typical observed field strengths, magnetic forces can then exceed thermal pressure and have important effects on cloud evolution (Heiles et al 1993, McKee et al 1993, ...
... magnetically dominated because the degree of ionization is high enough that the gas is strongly coupled to a magnetic field, and with typical observed field strengths, magnetic forces can then exceed thermal pressure and have important effects on cloud evolution (Heiles et al 1993, McKee et al 1993, ...
Follow-up observations of extremely metal
... our stars are on the low-metallicity edge of the distribution of halo stars, our uncertainties are likely somewhat higher than those inferred from these statistics. Fig. 3 shows DARMOUTH isochrones 3 , HB and AGB tracks compared to the stellar parameters derived with FERRE and its uncertainties. For ...
... our stars are on the low-metallicity edge of the distribution of halo stars, our uncertainties are likely somewhat higher than those inferred from these statistics. Fig. 3 shows DARMOUTH isochrones 3 , HB and AGB tracks compared to the stellar parameters derived with FERRE and its uncertainties. For ...
Galaxies Chapter Twenty
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
Powerpoint Presentation (large file)
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
Document
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
... Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited ...
observations and theory of star cluster formation
... Vogelaar and Wakker 1994). This power law structure includes both gas that is self-gravitating and gas that is non-self-gravitating, so the origin is not purely gravitational fragmentation. The most likely source is some combination of turbulence (see review in Falgarone and Phillips 1991), agglomer ...
... Vogelaar and Wakker 1994). This power law structure includes both gas that is self-gravitating and gas that is non-self-gravitating, so the origin is not purely gravitational fragmentation. The most likely source is some combination of turbulence (see review in Falgarone and Phillips 1991), agglomer ...
Star Cluster Trivia!
... They are extremely dense! At the centers of clusters, stars are sometimes as close together as Pluto is to the Sun! Because of high density, stars interact with each other! - Stars can collide - Complicated binary interactions help create cool binary sources, like X-ray binaries ...
... They are extremely dense! At the centers of clusters, stars are sometimes as close together as Pluto is to the Sun! Because of high density, stars interact with each other! - Stars can collide - Complicated binary interactions help create cool binary sources, like X-ray binaries ...
Large scale kinematics and dynamical modelling of the Milky Way
... the Galactic centre, but only 15 of their targets are within 8 pc from the Galactic centre, and therefore likely cluster members. McGinn et al. (1989) obtained integrated light spectra of selected fields with a 2000 (0.78 pc) aperture at 2.3 µm out to ∼4 pc (1.70 ) distance along the Galactic plane ...
... the Galactic centre, but only 15 of their targets are within 8 pc from the Galactic centre, and therefore likely cluster members. McGinn et al. (1989) obtained integrated light spectra of selected fields with a 2000 (0.78 pc) aperture at 2.3 µm out to ∼4 pc (1.70 ) distance along the Galactic plane ...
The chemical composition of two supergiants in the dwarf
... This result suggests that the [α(Mg)/Fe] ratio in WLM may be suppressed relative to solar abundances (also supported by differential abundances relative to similar stars in NGC 6822 and the SMC). The absolute Mg abundance, [Mg/H] = −0.62 is high relative to what is expected from the nebulae though, ...
... This result suggests that the [α(Mg)/Fe] ratio in WLM may be suppressed relative to solar abundances (also supported by differential abundances relative to similar stars in NGC 6822 and the SMC). The absolute Mg abundance, [Mg/H] = −0.62 is high relative to what is expected from the nebulae though, ...
Telescope Bernard Lyot/Narval The Observatory of Stellar Magnetism
... Mass dependent : dynamo and tachoclyne ...
... Mass dependent : dynamo and tachoclyne ...
Planetary nebula
![](https://commons.wikimedia.org/wiki/Special:FilePath/NGC6543.jpg?width=300)
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.