Open clusters and associations in the Gaia era
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
Variability in the CoRoT photometry of three hot O
... Results. A substantial number of frequencies is listed, but none can be convincingly identified as being connected to pulsations. The amplitude spectrum is dominated by red noise. Theoretical modelling shows that all three O-type stars can have excited modes but the relation between the theoretical ...
... Results. A substantial number of frequencies is listed, but none can be convincingly identified as being connected to pulsations. The amplitude spectrum is dominated by red noise. Theoretical modelling shows that all three O-type stars can have excited modes but the relation between the theoretical ...
A-level Physics (Specification A) Teacher guide Teacher guide
... mathematical relationship to absolute magnitude and distance. This allows for a discussion of the light year and parsec. How the temperature of a star is measured is then described, before combining luminosity and temperature in the Hertzsprung-Russell (H-R) diagram. The different types of stars – a ...
... mathematical relationship to absolute magnitude and distance. This allows for a discussion of the light year and parsec. How the temperature of a star is measured is then described, before combining luminosity and temperature in the Hertzsprung-Russell (H-R) diagram. The different types of stars – a ...
Gravitational Dynamics
... • M31 (now at 500 kpc) separated from MW a Hubble time ago • Large Magellanic Cloud has circulated our Galaxy for about 5 times at 50 kpc – argue both neighbours move with a typical 100-200km/s velocity relative to us. ...
... • M31 (now at 500 kpc) separated from MW a Hubble time ago • Large Magellanic Cloud has circulated our Galaxy for about 5 times at 50 kpc – argue both neighbours move with a typical 100-200km/s velocity relative to us. ...
Origin and formation of planetary systems
... showed that cores of typically about 10 MEarth are needed to gravitationally bind a comparable amount of nebula gas. Such envelopes were found to continue mass accretion up to a few tens of MEarth if the contraction of their envelopes was calculated for quasi-hydrostatic models (Bodenheimer and Poll ...
... showed that cores of typically about 10 MEarth are needed to gravitationally bind a comparable amount of nebula gas. Such envelopes were found to continue mass accretion up to a few tens of MEarth if the contraction of their envelopes was calculated for quasi-hydrostatic models (Bodenheimer and Poll ...
Observations of binary systems with pulsating components
... • Spectroscopic binaries: stars which exhibit periodic displacement of their spectral lines owing to Doppler effect caused by orbital motion. • Depending on components’ relative brightness, the observed spectrum will show the displacement of lines of one or both components (if a star is too faint, i ...
... • Spectroscopic binaries: stars which exhibit periodic displacement of their spectral lines owing to Doppler effect caused by orbital motion. • Depending on components’ relative brightness, the observed spectrum will show the displacement of lines of one or both components (if a star is too faint, i ...
Stellar Helium Burning in Other Universes: A
... stellar generations through the reaction 4 He + 8 Be → 12 C. This reaction is a natural channel to produce carbon — alpha particles are energetically favorable states, so that isotopes produced by adding together alpha particles would naively be the easiest to make. Note that in our universe the mos ...
... stellar generations through the reaction 4 He + 8 Be → 12 C. This reaction is a natural channel to produce carbon — alpha particles are energetically favorable states, so that isotopes produced by adding together alpha particles would naively be the easiest to make. Note that in our universe the mos ...
Stellar multiplicity and debris discs: an unbiased sample
... recently (see Mamajek et al. 2013; Kennedy et al. 2014). Thus, we may be missing some circumsecondary discs and thus focus on circumprimary or circumbinary discs only. Simultaneously to these Herschel observations, we have gathered literature data and adaptive optics (AO) observations (see Section 3 ...
... recently (see Mamajek et al. 2013; Kennedy et al. 2014). Thus, we may be missing some circumsecondary discs and thus focus on circumprimary or circumbinary discs only. Simultaneously to these Herschel observations, we have gathered literature data and adaptive optics (AO) observations (see Section 3 ...
F P US R
... uniquely in the RMS windows or where RMS observations are an important component of the multi-wavelength synergism. The RMS facilities will continue to contribute substantially to the study of the Sun and solar system objects, but the committee lacked the expertise to address these areas adequately, ...
... uniquely in the RMS windows or where RMS observations are an important component of the multi-wavelength synergism. The RMS facilities will continue to contribute substantially to the study of the Sun and solar system objects, but the committee lacked the expertise to address these areas adequately, ...
The Recent Star Formation Histories of M81 Group Dwarf Irregular
... The ability to translate resolved stellar populations into star formation histories (SFHs) has become an increasingly powerful method for understanding how star formation (SF) shapes galaxy evolution (e.g., Gallart et al. 2005). The power of the Hubble Space Telescope (HST) is truly being realized a ...
... The ability to translate resolved stellar populations into star formation histories (SFHs) has become an increasingly powerful method for understanding how star formation (SF) shapes galaxy evolution (e.g., Gallart et al. 2005). The power of the Hubble Space Telescope (HST) is truly being realized a ...
suggested
... photograph and are limited in density to less than about 300 hydrogen atoms per cc and are at a temperature of 50–100 K. The molecular clouds can have kinetic temperatures as low as 20 K (even 10 K) and any density above 300 per cc including the densities at which clouds collapse to form stars. Diffu ...
... photograph and are limited in density to less than about 300 hydrogen atoms per cc and are at a temperature of 50–100 K. The molecular clouds can have kinetic temperatures as low as 20 K (even 10 K) and any density above 300 per cc including the densities at which clouds collapse to form stars. Diffu ...
stochastic star formation and a (nearly) uniform stellar
... synthetic photometry in star clusters and galaxies, we compare the Hα and FUV luminosity in a sample of ∼450 nearby galaxies with models drawn from a universal Kroupa IMF and a modified IMF, the integrated galactic initial mass function (IGIMF). Once random sampling and time evolution are included, ...
... synthetic photometry in star clusters and galaxies, we compare the Hα and FUV luminosity in a sample of ∼450 nearby galaxies with models drawn from a universal Kroupa IMF and a modified IMF, the integrated galactic initial mass function (IGIMF). Once random sampling and time evolution are included, ...
A Test of Pre-Main-Sequence Lithium Depletion Models
... age of a PMS star whose distance is unknown, e.g. a young field star. In order to do this, we need to understand PMS lithium depletion very well. Most of the work comparing lithium depletion to HR diagram ages has been done in open clusters, focusing on comparing the cluster age derived from the lit ...
... age of a PMS star whose distance is unknown, e.g. a young field star. In order to do this, we need to understand PMS lithium depletion very well. Most of the work comparing lithium depletion to HR diagram ages has been done in open clusters, focusing on comparing the cluster age derived from the lit ...
Chapter 17
... 2. Radio observations of blazers indicated that they are double radio sources oriented in such a way that one jet is coming straight (or nearly so) at us. This was supported by observations of superluminal motion, motion that appears to occur faster than the speed of light. 3. Superluminal motion is ...
... 2. Radio observations of blazers indicated that they are double radio sources oriented in such a way that one jet is coming straight (or nearly so) at us. This was supported by observations of superluminal motion, motion that appears to occur faster than the speed of light. 3. Superluminal motion is ...
Evolution of low mass stars
... The HRD inspired an English astronomer, Sir Arthur Stanley Eddington (18821944), when Russell visited London and presented his diagram at a meeting of the Royal Astronomical Society in 1913 (Eisberg, 2002). At the time, Eddington was the chief assistant of the Royal Greenwich Observatory. In 1926 Ed ...
... The HRD inspired an English astronomer, Sir Arthur Stanley Eddington (18821944), when Russell visited London and presented his diagram at a meeting of the Royal Astronomical Society in 1913 (Eisberg, 2002). At the time, Eddington was the chief assistant of the Royal Greenwich Observatory. In 1926 Ed ...
The nature of the ultraluminous X-ray sources inside galaxies and
... 2002; Colbert & Ptak 2002). A recent study of a sample of nearby Seyfert galaxies with XMM-Newton has shown that Send offprint requests to: G. Burbidge, e-mail: [email protected] ...
... 2002; Colbert & Ptak 2002). A recent study of a sample of nearby Seyfert galaxies with XMM-Newton has shown that Send offprint requests to: G. Burbidge, e-mail: [email protected] ...
16 Hubble s Law and Dark Matter
... • Galaxy masses can be determined by rotation curves and galaxy clusters. • All measures show that a large amount of dark matter must exist. • Large galaxies probably formed from the merger of smaller ones. • Collisions are also important. • Merger of spiral galaxies probably results in an elliptica ...
... • Galaxy masses can be determined by rotation curves and galaxy clusters. • All measures show that a large amount of dark matter must exist. • Large galaxies probably formed from the merger of smaller ones. • Collisions are also important. • Merger of spiral galaxies probably results in an elliptica ...
SHELL BURNING STARS: Red Giants and Red Supergiants
... helium ignition is due to degeneracy of the core. When the core mass increases its central density increases too. The temperature within hydrogen burning shell and within the core also increase. At some point the rate of energy release due to helium burning becomes important for the heat balance nea ...
... helium ignition is due to degeneracy of the core. When the core mass increases its central density increases too. The temperature within hydrogen burning shell and within the core also increase. At some point the rate of energy release due to helium burning becomes important for the heat balance nea ...
A Star - Cloudy Nights
... Multiple Stars A few stars in the sky are actually multiple star systems, which can have anywhere from three to ten stars orbiting around a common point. Most of the time, there will be two or three brighter stars, with the rest being extremely faint or extremely close to each other. Almaak, or Ga ...
... Multiple Stars A few stars in the sky are actually multiple star systems, which can have anywhere from three to ten stars orbiting around a common point. Most of the time, there will be two or three brighter stars, with the rest being extremely faint or extremely close to each other. Almaak, or Ga ...
SAGE_prop
... onboard XMM-Newton and Chandra indicate considerably higher temperatures and densities than the Sun in most observed stellar coronae even in quiescence. The plasma parameters appear to depend on convection zone conditions and stellar rotation rates. Unfortunately, the high resolution instruments onb ...
... onboard XMM-Newton and Chandra indicate considerably higher temperatures and densities than the Sun in most observed stellar coronae even in quiescence. The plasma parameters appear to depend on convection zone conditions and stellar rotation rates. Unfortunately, the high resolution instruments onb ...
THE NEW GALAXY: Signatures of Its Formation
... In 1977, the ELS picture was challenged by Searle (see also Searle & Zinn 1978) who noted that Galactic globular clusters have a wide range of metal abundances essentially independent of radius from the Galactic Center. They suggested that this could be explained by a halo built up over an extended ...
... In 1977, the ELS picture was challenged by Searle (see also Searle & Zinn 1978) who noted that Galactic globular clusters have a wide range of metal abundances essentially independent of radius from the Galactic Center. They suggested that this could be explained by a halo built up over an extended ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.