Bamberg_VanGrootel - ORBi
... We applied the MAD code to all evolutionary sequences •“normal” CO-core DA models, 0.4 – 1.2Ms, log q(H)=-4.0 • ELM, C-core models: 0.125-0.4 Ms, log q(H)=-4.0 • ELM, He-core models: 0.125-0.4 Ms, log q(H)=-2.0 • 0.17Ms, He-core models, “thin” envelope log q(H)=-3.7 ...
... We applied the MAD code to all evolutionary sequences •“normal” CO-core DA models, 0.4 – 1.2Ms, log q(H)=-4.0 • ELM, C-core models: 0.125-0.4 Ms, log q(H)=-4.0 • ELM, He-core models: 0.125-0.4 Ms, log q(H)=-2.0 • 0.17Ms, He-core models, “thin” envelope log q(H)=-3.7 ...
Giant Planet Formation, Evolution, and Internal Structure
... a small fraction of heavy elements (high-Z material). The Z-component of the planetary envelope can be stellar, substellar, or super-stellar. If all the planetesimals reach the core without depositing mass in the envelope, the planetary envelope is likely to have a composition similar to the gas in ...
... a small fraction of heavy elements (high-Z material). The Z-component of the planetary envelope can be stellar, substellar, or super-stellar. If all the planetesimals reach the core without depositing mass in the envelope, the planetary envelope is likely to have a composition similar to the gas in ...
A Note on the Mixing Length Theory and Massive Star Evolution
... Figure 1 displays (in dotted lines) 3 envelope models of a 20 M with effective temperatures: 3600 K (top panels), 3900 K (middle panels) and 4200 K (lower panels). The dotted lines represent the results obtained with the convective envelope for late type supergiants following the original MLT (Vite ...
... Figure 1 displays (in dotted lines) 3 envelope models of a 20 M with effective temperatures: 3600 K (top panels), 3900 K (middle panels) and 4200 K (lower panels). The dotted lines represent the results obtained with the convective envelope for late type supergiants following the original MLT (Vite ...
Astronomy Astrophysics - Max Planck Institut für Radioastronomie
... (b) Gaseous inner disk: inside of the dust destruction radius, the gas continues to accrete towards the star, forming a gaseous inner accretion disk. The recombination line emission from ionized hydrogen in this disk might contribute to the line emission observed towards HAeBe stars. Muzerolle et al ...
... (b) Gaseous inner disk: inside of the dust destruction radius, the gas continues to accrete towards the star, forming a gaseous inner accretion disk. The recombination line emission from ionized hydrogen in this disk might contribute to the line emission observed towards HAeBe stars. Muzerolle et al ...
MHD seismology as a tool to diagnose the coronae of X
... heating of the corona of ξ-Boo. It should be noted that it is a binary K-Dwarf with the magnetized atmosphere and flaring activities. Observations of the decaying long period oscillation of a stellar megaflare by Anfinogentov et al. (2013): In the decay phase of the U-band light curve of a stellar m ...
... heating of the corona of ξ-Boo. It should be noted that it is a binary K-Dwarf with the magnetized atmosphere and flaring activities. Observations of the decaying long period oscillation of a stellar megaflare by Anfinogentov et al. (2013): In the decay phase of the U-band light curve of a stellar m ...
The Blue Stragglers in M67 and Single
... of stellar clusters cannot include all the light of a stellar population. 3.1. Fitting the Observed SEDs for Brightest Members For all the luminous high membership probability stragglers, among which 24 are classiÐed as blue stragglers (more luminous and bluer than the main-sequence turno† point) as ...
... of stellar clusters cannot include all the light of a stellar population. 3.1. Fitting the Observed SEDs for Brightest Members For all the luminous high membership probability stragglers, among which 24 are classiÐed as blue stragglers (more luminous and bluer than the main-sequence turno† point) as ...
$doc.title
... UV observations between 1981 July to 1983 March were reported in Shore et al. (1987). No photometric variability above ∼0.25mag. was found but a number of high excitation wind features (He , C , N ) were significantly variable. Two epochs of I band spectroscopy made by Shore et al. (1987; obtai ...
... UV observations between 1981 July to 1983 March were reported in Shore et al. (1987). No photometric variability above ∼0.25mag. was found but a number of high excitation wind features (He , C , N ) were significantly variable. Two epochs of I band spectroscopy made by Shore et al. (1987; obtai ...
Astronomy Astrophysics
... of this series we presented the photometric observations and determined the existence of starspot cycles and their correlation with the global stellar properties. In the present paper we investigate the surface differential rotation (SDR). The periodogram analysis of the photometric data time series ...
... of this series we presented the photometric observations and determined the existence of starspot cycles and their correlation with the global stellar properties. In the present paper we investigate the surface differential rotation (SDR). The periodogram analysis of the photometric data time series ...
The stellar populations in the low-luminosity, early
... test initial mass functions (IMF) in galaxies, supporting a steeper integrated galactic IMF with increasing galaxy mass and decreasing star formation rate (Recchi, Calura & Kroupa 2009). LLEs provide important tests of scaling relations with mass and luminosity in general, since they are at one extr ...
... test initial mass functions (IMF) in galaxies, supporting a steeper integrated galactic IMF with increasing galaxy mass and decreasing star formation rate (Recchi, Calura & Kroupa 2009). LLEs provide important tests of scaling relations with mass and luminosity in general, since they are at one extr ...
The Formation of Massive Stars - Max-Planck
... counterpart in the GLIMPSE data. While this could also indicate a genuine HMSC, they found relatively high temperatures [~33 K from NH3(1,1) and (2,2)], an increasing N2H+(1–0) line width from the core edge to the core center, and so-called “green fuzzy” mid-infrared emission at the edge of the core ...
... counterpart in the GLIMPSE data. While this could also indicate a genuine HMSC, they found relatively high temperatures [~33 K from NH3(1,1) and (2,2)], an increasing N2H+(1–0) line width from the core edge to the core center, and so-called “green fuzzy” mid-infrared emission at the edge of the core ...
- UCL Discovery
... Pelupessy, van der Werf & Icke 2004). The thermal energy of the feedback particles is calculated with the SPH scheme with radiative cooling and additional heating from stellar wind, SNe II and SNe Ia. Eight out of the 19 feedback particles spend no time being stars and immediately become SNe II feed ...
... Pelupessy, van der Werf & Icke 2004). The thermal energy of the feedback particles is calculated with the SPH scheme with radiative cooling and additional heating from stellar wind, SNe II and SNe Ia. Eight out of the 19 feedback particles spend no time being stars and immediately become SNe II feed ...
Forming different planetary systems ∗
... et al. 2011b). Through population synthesis, N-body and hydrodynamical simulations, the planet formation processes have been well revealed but are still far from fully understood. In this paper, we focus on recent progress in the theory of detection and formation of solar type stars, either around s ...
... et al. 2011b). Through population synthesis, N-body and hydrodynamical simulations, the planet formation processes have been well revealed but are still far from fully understood. In this paper, we focus on recent progress in the theory of detection and formation of solar type stars, either around s ...
The evolution of Red Supergiants to supernova in the LMC cluster
... be small compared to the age of the cluster. Hence, we can assume that all stars currently in the RSG phase had the same initial mass to within a few tenths of a solar mass. Since the stars’ masses are so similar, they will all follow almost the same path across the H-R diagram. Differences in lumin ...
... be small compared to the age of the cluster. Hence, we can assume that all stars currently in the RSG phase had the same initial mass to within a few tenths of a solar mass. Since the stars’ masses are so similar, they will all follow almost the same path across the H-R diagram. Differences in lumin ...
The Stellar Initial Mass Function and Beyond
... mass of the order of one solar mass. Thus they all appear to be consistent with the view that typical stellar masses derive from the masses of small prestellar clumps created by cloud fragmentation processes. These results may pose a problem for the hypothesis that forming stars continue to accrete ...
... mass of the order of one solar mass. Thus they all appear to be consistent with the view that typical stellar masses derive from the masses of small prestellar clumps created by cloud fragmentation processes. These results may pose a problem for the hypothesis that forming stars continue to accrete ...
On the absolute age of the globular cluster M71
... of the candidate cluster stars with appropriate isochrones. We found an age of 12±2.0 Gyr, in good agreement with literature values. Beside the classical isochrone comparison, we also estimated the age by using the ’knee method’, which is independent by the uncertainties affecting the cluster distan ...
... of the candidate cluster stars with appropriate isochrones. We found an age of 12±2.0 Gyr, in good agreement with literature values. Beside the classical isochrone comparison, we also estimated the age by using the ’knee method’, which is independent by the uncertainties affecting the cluster distan ...
Two possible circumbinary planets in the eclipsing post
... 1993). Theoretical studies have indicated that circumbinary planets can be formed and survive for a long time (Moriwaki & Nakagawa 2004; Quintana & Lissauer 2006). Characterization of such planets in different evolutionary stages of the host binary is crucial to constrain and test the formation and ...
... 1993). Theoretical studies have indicated that circumbinary planets can be formed and survive for a long time (Moriwaki & Nakagawa 2004; Quintana & Lissauer 2006). Characterization of such planets in different evolutionary stages of the host binary is crucial to constrain and test the formation and ...
A 25 micron search for Vega-like disks around main
... Abstract. We present an ISO 25 µm photometric survey of a sample of 81 nearby main-sequence stars in order to determine the incidence of “warm” dust disks. All stars were detected by ISO. We used an empirical relation to estimate the photospheric flux of the stars at 25 µm. We find 5 stars (6%) with ...
... Abstract. We present an ISO 25 µm photometric survey of a sample of 81 nearby main-sequence stars in order to determine the incidence of “warm” dust disks. All stars were detected by ISO. We used an empirical relation to estimate the photospheric flux of the stars at 25 µm. We find 5 stars (6%) with ...
Pre-main sequence stars, emission stars and recent star formation in
... studied here are Berkeley 86, NGC 6910, IC 4996, Berkeley 87 and Biurakan 2. We aim to combine the ages and the star formation duration in these clusters to understand how the star formation proceeded in the Cygnus region. A number of stars are known to show Hα emission in this region. The photometr ...
... studied here are Berkeley 86, NGC 6910, IC 4996, Berkeley 87 and Biurakan 2. We aim to combine the ages and the star formation duration in these clusters to understand how the star formation proceeded in the Cygnus region. A number of stars are known to show Hα emission in this region. The photometr ...
variable star type designations in vsx
... A pipe character ( | ) between two different types signifies a logical OR; the classification is uncertain and all possible types are indicated. An example of this is ELL|DSCT, where the star may be an ellipsoidal binary system or a DSCT-type pulsating variable with half the given period. A plus cha ...
... A pipe character ( | ) between two different types signifies a logical OR; the classification is uncertain and all possible types are indicated. An example of this is ELL|DSCT, where the star may be an ellipsoidal binary system or a DSCT-type pulsating variable with half the given period. A plus cha ...
Carbon-enhanced metal-poor stars: the most pristine - HAL
... Context. Carbon-enhanced metal poor stars (CEMP) form a significant proportion of the metal-poor stars, their origin is not well understood, and this carbon-enhancement appears in stars that exhibit different abundance patterns. Aims. Three very metal-poor C-rich turnoff stars were selected from the ...
... Context. Carbon-enhanced metal poor stars (CEMP) form a significant proportion of the metal-poor stars, their origin is not well understood, and this carbon-enhancement appears in stars that exhibit different abundance patterns. Aims. Three very metal-poor C-rich turnoff stars were selected from the ...
The incidence of stellar mergers and mass gainers among massive
... coalescence we assume in our standard simulations that a fraction µloss = 0.1 of the system mass is lost during the merger taking away the excess angular momentum. When investigating the uncertainties we consider the case that mass loss can be neglected, µloss = 0, and µloss = 0.25. The merger produ ...
... coalescence we assume in our standard simulations that a fraction µloss = 0.1 of the system mass is lost during the merger taking away the excess angular momentum. When investigating the uncertainties we consider the case that mass loss can be neglected, µloss = 0, and µloss = 0.25. The merger produ ...
Direct Imaging discovery of a second planet candidate
... Context. Direct Imaging has developed into a very successful technique for the detection of exoplanets in wide orbits, especially around young stars. Directly imaged planets can both be followed astrometrically on their orbits and observed spectroscopically, and thus provide an essential tool for ou ...
... Context. Direct Imaging has developed into a very successful technique for the detection of exoplanets in wide orbits, especially around young stars. Directly imaged planets can both be followed astrometrically on their orbits and observed spectroscopically, and thus provide an essential tool for ou ...
HST observations of the field star population in the Large Magellanic
... of star formation 2-4 Gyr ago, with the exact timing depending on the choice of stellar evolution models. Vallenari et al. use the same method and similar data to investigate the stellar population in six fields, and reach a similar conclusion. They also suggest that the time of onset of the burst v ...
... of star formation 2-4 Gyr ago, with the exact timing depending on the choice of stellar evolution models. Vallenari et al. use the same method and similar data to investigate the stellar population in six fields, and reach a similar conclusion. They also suggest that the time of onset of the burst v ...
A self-consistent empirical model atmosphere, abundance and
... Context. Chemically peculiar (CP) stars are unique natural laboratories for the investigation of the microscopic diffusion processes of chemical elements. The element segregation under the influence of gravity and radiation pressure leads to the appearance of strong abundance gradients in the atmosph ...
... Context. Chemically peculiar (CP) stars are unique natural laboratories for the investigation of the microscopic diffusion processes of chemical elements. The element segregation under the influence of gravity and radiation pressure leads to the appearance of strong abundance gradients in the atmosph ...
A large-scale CO survey of the Rosette Molecular Cloud: assessing
... We present a new large-scale survey of the J = 3–2 12 CO emission covering 4.8 deg2 around the Rosette Nebula. The results reveal the complex dynamics of the molecular gas in this region. We identify about 2000 compact gas clumps having a mass distribution given by dN /dM ∼ M −1.8 , with no dependen ...
... We present a new large-scale survey of the J = 3–2 12 CO emission covering 4.8 deg2 around the Rosette Nebula. The results reveal the complex dynamics of the molecular gas in this region. We identify about 2000 compact gas clumps having a mass distribution given by dN /dM ∼ M −1.8 , with no dependen ...
Planetary nebula
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.