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 ...
Towards the understanding of the deepest layers of solar
... I would like to start by thanking both my supervisors, Dra. Margarida Cunha and Prof. Dr. Jørgen Christensen-Dalsgaard, without whom the realization of this thesis would not have been possible. I would like to give a very special thank to Prof. Dr. Jørgen ChristensenDalsgaard for his hospitality and ...
... I would like to start by thanking both my supervisors, Dra. Margarida Cunha and Prof. Dr. Jørgen Christensen-Dalsgaard, without whom the realization of this thesis would not have been possible. I would like to give a very special thank to Prof. Dr. Jørgen ChristensenDalsgaard for his hospitality and ...
Feedback from winds and supernovae in massive stellar clusters – I
... may be occurring within 30 Doradus. Lopez et al. (2011) also conclude that direct stellar radiation pressure dominates the interior dynamics, but this claim has proved far more controversial, and other works argue in favour of the thermal pressure of hot X-ray emitting plasma shaping the large-scale ...
... may be occurring within 30 Doradus. Lopez et al. (2011) also conclude that direct stellar radiation pressure dominates the interior dynamics, but this claim has proved far more controversial, and other works argue in favour of the thermal pressure of hot X-ray emitting plasma shaping the large-scale ...
The Recent Star Formation Histories of M81 Group Dwarf Irregular
... We present observations and analysis of nine dwarf irregular galaxies (dIs) in the M81 Group taken with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The nine galaxy sample (the Garland, M81 Dwarf A, DDO 53, Ho IX, Ho I, DDO 165, NGC 2366, Ho II, and IC 2574) spans 6 magnitudes ...
... We present observations and analysis of nine dwarf irregular galaxies (dIs) in the M81 Group taken with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The nine galaxy sample (the Garland, M81 Dwarf A, DDO 53, Ho IX, Ho I, DDO 165, NGC 2366, Ho II, and IC 2574) spans 6 magnitudes ...
The Age and Stellar Parameters of the Procyon Binary System
... determination), is near and bright enough that the component radii, effective temperatures and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are available from HST ima ...
... determination), is near and bright enough that the component radii, effective temperatures and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are available from HST ima ...
They might be giants: luminosity class, planet frequency, and planet
... (JHK) magnitudes; stellar parameters are estimated by forward modeling of the photometric data with the synthetic spectra of Castelli & Kurucz (2004), and effective temperature Tef f , gravity log g, and metallicity [M/H] as free parameters. Stellar mass and distance are then estimated using luminos ...
... (JHK) magnitudes; stellar parameters are estimated by forward modeling of the photometric data with the synthetic spectra of Castelli & Kurucz (2004), and effective temperature Tef f , gravity log g, and metallicity [M/H] as free parameters. Stellar mass and distance are then estimated using luminos ...
Blue horizontal branch stars in the Sloan Digital Sky Survey:
... BHB stars have very characteristic colors in the high-Galactic latitude stellar sample observed by the SDSS imaging survey, and photometric selection of candidate objects is straightforward. BHB stars are bluer in g − r than most halo stars because the halo main sequence turnoff lies at spectral typ ...
... BHB stars have very characteristic colors in the high-Galactic latitude stellar sample observed by the SDSS imaging survey, and photometric selection of candidate objects is straightforward. BHB stars are bluer in g − r than most halo stars because the halo main sequence turnoff lies at spectral typ ...
STELLAR SPECTRA A. Basic Line Formation
... band that is therefore called the “main sequence”. Some other stars lie on a branch to the upper right called the “giant branch”. Their presence implies that another parameter than only the spectral type is needed to define a star, the “luminosity classification” I–II–III–IV–V. Stars with luminosity ...
... band that is therefore called the “main sequence”. Some other stars lie on a branch to the upper right called the “giant branch”. Their presence implies that another parameter than only the spectral type is needed to define a star, the “luminosity classification” I–II–III–IV–V. Stars with luminosity ...
they might be giants: luminosity class, planet occurrence, and planet
... star. Likewise, the transit signal produced by a planet of a given radius - and hence its detectability around a star in the survey - also depends on stellar radius. If some target stars are actually larger or even giant stars, then planets are less likely to be detected in that sample, which means ...
... star. Likewise, the transit signal produced by a planet of a given radius - and hence its detectability around a star in the survey - also depends on stellar radius. If some target stars are actually larger or even giant stars, then planets are less likely to be detected in that sample, which means ...
Massive Star Formation in the Galactic Center
... 3. Present-day star formation in the GC Present-day star formation in the GC is somewhat subdued compared to the episodes that produced the massive clusters we now see. A dozen or so ultra-compact HII regions are distributed throughout the central 50 pc, each containing one or a few O-stars still em ...
... 3. Present-day star formation in the GC Present-day star formation in the GC is somewhat subdued compared to the episodes that produced the massive clusters we now see. A dozen or so ultra-compact HII regions are distributed throughout the central 50 pc, each containing one or a few O-stars still em ...
Links Between Pulsation and Line-Driven Mass Loss in Massive Stars
... • And most Be stars are not in close binary systems. • They thus lack outside mass source to fall into disk. ...
... • And most Be stars are not in close binary systems. • They thus lack outside mass source to fall into disk. ...
Here
... the past three year. I have learnt much from him in this time, from the details of stellar evolution through the differences between decanters for port and claret to the intricacies of English grammar (though I’m still struggling with the latter, apparently). I may not have been the model student bu ...
... the past three year. I have learnt much from him in this time, from the details of stellar evolution through the differences between decanters for port and claret to the intricacies of English grammar (though I’m still struggling with the latter, apparently). I may not have been the model student bu ...
Pioneering Women in the Spectral Classification of Stars
... hydrogen emission lines. Hence, when she discovered in 1890 that R Caeli showed a similar spectrum, she surmised that a Mira-type variable could be identified as such from the observation of a single spectrum, which expedited the discovery of Mira-type variables as compared to the usual photographic ...
... hydrogen emission lines. Hence, when she discovered in 1890 that R Caeli showed a similar spectrum, she surmised that a Mira-type variable could be identified as such from the observation of a single spectrum, which expedited the discovery of Mira-type variables as compared to the usual photographic ...
stellar rotation in m35: mass–period relations, spin
... 2000), and by allowing the saturation threshold to depend on the stellar mass. The physical meaning of “saturation” is still unclear. During the pre-main-sequence (PMS) phase, large dispersions and substructure (bimodalities) in the rotation-period distributions has also been observed for coeval ste ...
... 2000), and by allowing the saturation threshold to depend on the stellar mass. The physical meaning of “saturation” is still unclear. During the pre-main-sequence (PMS) phase, large dispersions and substructure (bimodalities) in the rotation-period distributions has also been observed for coeval ste ...
Studying explosive phenomena in astrophysics by the example of
... The formation of the first stars hundreds of millions of years after the Big-Bang marks the end of the so-called Dark Ages. Currently, we have no direct observations on how the primordial stars (Population III stars) formed, but according to modern theory of stellar evolution these stars should be v ...
... The formation of the first stars hundreds of millions of years after the Big-Bang marks the end of the so-called Dark Ages. Currently, we have no direct observations on how the primordial stars (Population III stars) formed, but according to modern theory of stellar evolution these stars should be 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 ...
Draft paper (submitted to MNRAS)
... particular, since it allows low density gas to accumulate in a galaxy, where it can fuel discrete star formation episodes triggered even by minor accretion events. Ricotti & Gnedin (2005) have also argued, on the basis of numerical simulations, that diversity in dwarf SFHs might actually be a relic ...
... particular, since it allows low density gas to accumulate in a galaxy, where it can fuel discrete star formation episodes triggered even by minor accretion events. Ricotti & Gnedin (2005) have also argued, on the basis of numerical simulations, that diversity in dwarf SFHs might actually be a relic ...
Finding high-redshift dark stars with the James Webb Space
... matter distribution outside the star and the resultant rate at which WIMPs are captured by the nuclear scattering process. Progress has been made in including some early-stage effects, like gravitationally-contracted dark matter (Iocco et al. 2008) and gas accretion (Umeda et al. 2009), but the real ...
... matter distribution outside the star and the resultant rate at which WIMPs are captured by the nuclear scattering process. Progress has been made in including some early-stage effects, like gravitationally-contracted dark matter (Iocco et al. 2008) and gas accretion (Umeda et al. 2009), but the real ...
The Massive Star Population of Cygnus OB2
... rotating stellar evolution models, from which stellar masses and ages are calculated. The star formation history and mass function of the association are assessed, and both are found to be heavily influenced by the evolution of the most massive stars to their end states. We find that the mass functi ...
... rotating stellar evolution models, from which stellar masses and ages are calculated. The star formation history and mass function of the association are assessed, and both are found to be heavily influenced by the evolution of the most massive stars to their end states. We find that the mass functi ...
S-process in extremely metal-poor, low-mass stars
... observations, disfavoring the self-enrichment scenario. In addition, most observed EMP stars are not evolved past the heliumcore flash to have undergone PIE. The positive correlation between carbon and barium abundances observed in EMP stars indicates that carbon and s-process elements might have a ...
... observations, disfavoring the self-enrichment scenario. In addition, most observed EMP stars are not evolved past the heliumcore flash to have undergone PIE. The positive correlation between carbon and barium abundances observed in EMP stars indicates that carbon and s-process elements might have a ...
Ages of young stars
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
Ages of Young Stars
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
Session 1: Stellar winds, diagnostics across the electromagnetic
... Polarimetry is an important observational technique in the study of hot stars. Practiced across the full range of wavelengths, polarimetry provides a window into a variety of stellar phenomena not accessible by other means. For example, polarimetry constrains the properties of circumstellar disks, u ...
... Polarimetry is an important observational technique in the study of hot stars. Practiced across the full range of wavelengths, polarimetry provides a window into a variety of stellar phenomena not accessible by other means. For example, polarimetry constrains the properties of circumstellar disks, u ...
Theory of cooling neutron stars versus observations
... Let us summarize the main neutrino emission mechanisms in the neutron star core. They are strongly affected by baryon superfluidity. More details can be found, e.g., in Refs. [18, 19, 20]. Neutrino emission in nonsuperfluid cores. The major neutrino mechanisms in nucleon matter of the outer core (ρ ...
... Let us summarize the main neutrino emission mechanisms in the neutron star core. They are strongly affected by baryon superfluidity. More details can be found, e.g., in Refs. [18, 19, 20]. Neutrino emission in nonsuperfluid cores. The major neutrino mechanisms in nucleon matter of the outer core (ρ ...
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 ...