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Turbulent convection in stellar interiors
... • Energy transport processes: • Photons diffusion (radiative zone) ...
... • Energy transport processes: • Photons diffusion (radiative zone) ...
An absence of ex-companion stars in the type Ia supernova remnant
... A type Ia supernova is thought to begin with the explosion of a white dwarf star1. The explosion could be triggered by the merger of two white dwarfs2,3 (a ‘double-degenerate’ origin), or by mass transfer from a companion star4,5 (the ‘single-degenerate’ path). The identity of the progenitor is stil ...
... A type Ia supernova is thought to begin with the explosion of a white dwarf star1. The explosion could be triggered by the merger of two white dwarfs2,3 (a ‘double-degenerate’ origin), or by mass transfer from a companion star4,5 (the ‘single-degenerate’ path). The identity of the progenitor is stil ...
Astronomy Astrophysics
... that are old enough for their stellar content to be dynamically relaxed (Binney & Tremaine 1987). Observationally, it is not an easy task to detect mass segregation since, ideally, one has to go deep photometrically to attain the cluster’s low mass stars, and field stars contamination has to be prop ...
... that are old enough for their stellar content to be dynamically relaxed (Binney & Tremaine 1987). Observationally, it is not an easy task to detect mass segregation since, ideally, one has to go deep photometrically to attain the cluster’s low mass stars, and field stars contamination has to be prop ...
17.1 Introduction
... becomes transparent again, thereby allowing more radiation to pass. Without that added source of heating the local pressure drops, the expansion stops, the star recollapses, and the cycle repeats. The alternate trapping and releasing of energy in the helium ionization layer ultimately gives rise to ...
... becomes transparent again, thereby allowing more radiation to pass. Without that added source of heating the local pressure drops, the expansion stops, the star recollapses, and the cycle repeats. The alternate trapping and releasing of energy in the helium ionization layer ultimately gives rise to ...
PowerPoint - Division for Planetary Sciences
... Knowledge of these properties enable us to infer much about what Eris is like inside and on the surface. ...
... Knowledge of these properties enable us to infer much about what Eris is like inside and on the surface. ...
Role of column density in the formation of stars
... here that these relations can be accounted for if, in a forming galaxy with an isothermal mass distribution, gas with a column density above about 8 M pc−2 goes into stars, whereas gas with a column density above about 2 g cm−2 (104 M pc−2 ) goes into a central black hole. The lower critical value ...
... here that these relations can be accounted for if, in a forming galaxy with an isothermal mass distribution, gas with a column density above about 8 M pc−2 goes into stars, whereas gas with a column density above about 2 g cm−2 (104 M pc−2 ) goes into a central black hole. The lower critical value ...
Chapter 9 Post-main sequence evolution through helium burning
... degenerate, a very strong density contrast has developed between the core and the envelope. The envelope is so extended that it exerts very little weight on the compact core, while there is a very large pressure gradient between core and envelope. The pressure at the bottom of the envelope (see eq. ...
... degenerate, a very strong density contrast has developed between the core and the envelope. The envelope is so extended that it exerts very little weight on the compact core, while there is a very large pressure gradient between core and envelope. The pressure at the bottom of the envelope (see eq. ...
Preliminary results of the Be stars proportion in LMC open
... Be phenomenon is transient. Be stars are fast rotators, reaching ~80% of their angular critical velocity. The fast rotation is a major factor in the matter ejection leading to the circumstellar disk and the emission, however it cannot explain alone the matter ejection and other mechanisms such as a ...
... Be phenomenon is transient. Be stars are fast rotators, reaching ~80% of their angular critical velocity. The fast rotation is a major factor in the matter ejection leading to the circumstellar disk and the emission, however it cannot explain alone the matter ejection and other mechanisms such as a ...
The 3-D shaping of NGC 6741: A massive, fast
... surrounded by a sharp low-excitation skin (the ionization front), and embedded in a spherical (radius 0.080 pc), almostneutral, high-density (n(H I) 7 × 103 atoms cm−3 ) halo containing a large fraction of the nebular mass (Mhalo ≥ 0.20 M ). The kinematics, physical conditions and ionic structu ...
... surrounded by a sharp low-excitation skin (the ionization front), and embedded in a spherical (radius 0.080 pc), almostneutral, high-density (n(H I) 7 × 103 atoms cm−3 ) halo containing a large fraction of the nebular mass (Mhalo ≥ 0.20 M ). The kinematics, physical conditions and ionic structu ...
Why do some galaxies stop making new stars?
... A distinctive feature of elliptical galaxies is their ellipsoidal shapes, much like an Aussie rules or rugby ball. The Milky Way, and many other large star-forming galaxies, are spiral galaxies. In spiral galaxies, ...
... A distinctive feature of elliptical galaxies is their ellipsoidal shapes, much like an Aussie rules or rugby ball. The Milky Way, and many other large star-forming galaxies, are spiral galaxies. In spiral galaxies, ...
PPT - IAC
... R Aqr nebula known since 1921 (Lampland 1923 PAAS 4, 319), but the concept that a large fraction of symbiotic Miras have (collimated) nebulae very similar to PNe, which illustrate the potential importance of binary interactions for the shaping of PNe, started growing from the moment that Hugo discov ...
... R Aqr nebula known since 1921 (Lampland 1923 PAAS 4, 319), but the concept that a large fraction of symbiotic Miras have (collimated) nebulae very similar to PNe, which illustrate the potential importance of binary interactions for the shaping of PNe, started growing from the moment that Hugo discov ...
HR Diagram Explorer
... There is a correlation between a main sequence star's mass and its luminosity. Stars that have higher and are on the main sequence have a greater mass than fainter stars. The mass luminosity relation was discovered by in 1924. It says that the stars luminosity is proportional to the power of its mas ...
... There is a correlation between a main sequence star's mass and its luminosity. Stars that have higher and are on the main sequence have a greater mass than fainter stars. The mass luminosity relation was discovered by in 1924. It says that the stars luminosity is proportional to the power of its mas ...
Kepler-20: A sun-like star with three sub-neptune
... that our error estimates of the other parameters are inflated to account for this possibility. Similarly, we are not able to detect the RV signals Ki for Kepler-20d, K00070.04, or K00070.05, but by including these parameters, we include any inflation these may imply for the uncertainties on the mass ...
... that our error estimates of the other parameters are inflated to account for this possibility. Similarly, we are not able to detect the RV signals Ki for Kepler-20d, K00070.04, or K00070.05, but by including these parameters, we include any inflation these may imply for the uncertainties on the mass ...
Effects of M dwarf magnetic fields on potentially habitable planets
... We investigate the effect of the magnetic fields of M dwarf (dM) stars on potentially habitable Earth-like planets. These fields can reduce the size of planetary magnetospheres to such an extent that a significant fraction of the planet’s atmosphere may be exposed to erosion by the stellar wind. We ...
... We investigate the effect of the magnetic fields of M dwarf (dM) stars on potentially habitable Earth-like planets. These fields can reduce the size of planetary magnetospheres to such an extent that a significant fraction of the planet’s atmosphere may be exposed to erosion by the stellar wind. We ...
Determining the Cepheid Period–Luminosity Relation Using
... (Freedman et al., 2001). We find a significant effect in the sense that metal-poor stars are fainter than metal-rich stars by 0.23 ± 0.1 mag per dex. The size of the effect is similar to the most recent one adopted by the Key Project group. This is a very reassuring result as our method is entirely ...
... (Freedman et al., 2001). We find a significant effect in the sense that metal-poor stars are fainter than metal-rich stars by 0.23 ± 0.1 mag per dex. The size of the effect is similar to the most recent one adopted by the Key Project group. This is a very reassuring result as our method is entirely ...
February - Saguaro Astronomy Club
... companion a white dwarf, Sirius B. I have tried numerous times to try to split this double, but have been unsuccessful to this point. Canis Major is the hunting companion of Orion. With a little imagination, you can make out the stick figure of this dog in the sky. As an interesting note, the phrase ...
... companion a white dwarf, Sirius B. I have tried numerous times to try to split this double, but have been unsuccessful to this point. Canis Major is the hunting companion of Orion. With a little imagination, you can make out the stick figure of this dog in the sky. As an interesting note, the phrase ...
The End of the Dark Ages
... the simulations are the same as those discussed above. For a Salpeter IMF, the volume of the ionized region is smaller by a factor 8, although the shape is very similar to the one for a Larson IMF case at an earlier stage, roughly corresponding to 10 Myr. This was expected from the differences betwe ...
... the simulations are the same as those discussed above. For a Salpeter IMF, the volume of the ionized region is smaller by a factor 8, although the shape is very similar to the one for a Larson IMF case at an earlier stage, roughly corresponding to 10 Myr. This was expected from the differences betwe ...
The James Webb Space Telescope - HubbleSOURCE
... Hubble Space Telescope • HST has made and continues to make huge impact on astronomy and the public – Cosmic distance scale – Accelerating universe & dark energy – Supermassive BH in Galaxy centers ...
... Hubble Space Telescope • HST has made and continues to make huge impact on astronomy and the public – Cosmic distance scale – Accelerating universe & dark energy – Supermassive BH in Galaxy centers ...
Dark Matter Capture in the first stars
... • THE POWER OF DARKNESS: DM is only 2% of the mass of the star but provides the heat source • Dark stars are made of DM but are not dark: they do shine, although they’re cooler than standard early stars. Luminosity 140 solar ...
... • THE POWER OF DARKNESS: DM is only 2% of the mass of the star but provides the heat source • Dark stars are made of DM but are not dark: they do shine, although they’re cooler than standard early stars. Luminosity 140 solar ...
The Carina Dwarf Spheroidal Galaxy: A Goldmine for Cosmology
... giant late-type galaxies to lower mass. On the other hand, the FL of dwarf sphe roidals (dSphs) in a four-dimensional parameter space (total mass, surface brightness, rotation velocity and Z) is also linear and very tight, but is not an extra polation of the scaling relations of giant early-type ...
... giant late-type galaxies to lower mass. On the other hand, the FL of dwarf sphe roidals (dSphs) in a four-dimensional parameter space (total mass, surface brightness, rotation velocity and Z) is also linear and very tight, but is not an extra polation of the scaling relations of giant early-type ...
Radio emissions from terrestrial planets around white dwarfs
... tends to mildly overestimate the density, and therefore the drag, in comparison to the Soker (1992) model, particularly during the last pulses and collapse to a proto-white dwarf. We note here that the approximate expression for the density profile (Eq. (12) in Soker & Livio 1994), used in this cont ...
... tends to mildly overestimate the density, and therefore the drag, in comparison to the Soker (1992) model, particularly during the last pulses and collapse to a proto-white dwarf. We note here that the approximate expression for the density profile (Eq. (12) in Soker & Livio 1994), used in this cont ...
THE STRUCTURE OF SURFACE H2O LAYERS OF ICE
... (Mayor & Queloz 1995), more than 800 exoplanets have been detected as of 2013 March, owing to improvements in both observational instruments and analysis methods. Although most known exoplanets are gas giants, estimates based on both theory and observations indicate that terrestrial planets are also ...
... (Mayor & Queloz 1995), more than 800 exoplanets have been detected as of 2013 March, owing to improvements in both observational instruments and analysis methods. Although most known exoplanets are gas giants, estimates based on both theory and observations indicate that terrestrial planets are also ...
Peak Bagging of red giant stars observed by Kepler: first results with
... red giants (RGs) has encountered a substantial increase, especially thanks to the advent of the spacebased photometric missions CoRoT (e.g. [20,19]) and Kepler (e.g. [16, 15]), where the latter allowed also for the study of RGs in open clusters (e.g. [25,7]). The discovery of so-called mixed modes [ ...
... red giants (RGs) has encountered a substantial increase, especially thanks to the advent of the spacebased photometric missions CoRoT (e.g. [20,19]) and Kepler (e.g. [16, 15]), where the latter allowed also for the study of RGs in open clusters (e.g. [25,7]). The discovery of so-called mixed modes [ ...
REVIEWS 18 years of science with the Hubble Space Telescope Julianne J. Dalcanton
... star becomes exhausted, the star is forced to undergo dramatic evolution. During this evolution, the star expands drastically, sheds much of its mass and either explodes or fades away, leaving behind a bizarre stellar remnant (such as a white dwarf, neutron star or black hole). These late phases of ...
... star becomes exhausted, the star is forced to undergo dramatic evolution. During this evolution, the star expands drastically, sheds much of its mass and either explodes or fades away, leaving behind a bizarre stellar remnant (such as a white dwarf, neutron star or black hole). These late phases of ...
Booklet - Centrum Astronomiczne im. M.Kopernika PAN
... luminosities. Among the 12 stars, five were found to show absorption lines of Tc. However, there is no clear correlation between period change type and Tc presence. We identify one star that probably changed its spectral type from SC to C by 3DUP recently, one star that possibly switches its pulsati ...
... luminosities. Among the 12 stars, five were found to show absorption lines of Tc. However, there is no clear correlation between period change type and Tc presence. We identify one star that probably changed its spectral type from SC to C by 3DUP recently, one star that possibly switches its pulsati ...
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.