PRESS 2001 Project Report - Hong Kong University of Science and
... Half or more of all stars in the universe are in orbit around another star or stars. In most of these multiple-star systems, there is a type of system which consists of two stars only, known as a binary star system, whose components may be separated by a large fraction of a light year, or they may b ...
... Half or more of all stars in the universe are in orbit around another star or stars. In most of these multiple-star systems, there is a type of system which consists of two stars only, known as a binary star system, whose components may be separated by a large fraction of a light year, or they may b ...
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... lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved with the help of spectral synthesis techniques including large numbers of molecular lines. Thus, the counterparts to the catalogues ...
... lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved with the help of spectral synthesis techniques including large numbers of molecular lines. Thus, the counterparts to the catalogues ...
Abundances and possible diffusion of elements in M 67 stars⋆
... Effective temperatures: in establishing the effective temperatures of the programme stars we have used the colours (V − Ks ) and (V − Ic ), as well as the wings of the Hα lines, as primary indicators. We preferred the use of colours and Hα-line profiles to the use of metal-lines of different excitation ...
... Effective temperatures: in establishing the effective temperatures of the programme stars we have used the colours (V − Ks ) and (V − Ic ), as well as the wings of the Hα lines, as primary indicators. We preferred the use of colours and Hα-line profiles to the use of metal-lines of different excitation ...
![Cosmic variance in [O/Fe] in the Galactic disk](http://s1.studyres.com/store/data/014331057_1-996ec6eddf93071c5e835624d4620c7e-300x300.png)
Cosmic variance in [O/Fe] in the Galactic disk
... and the available distances are not very accurate. On the other hand, the intrinsic uncertainties in the determination of abundances by the ASPCAP pipeline are very small, and therefore we prefer to use chemistry to distinguish the membership of stars in one of the two disk populations. From all the ...
... and the available distances are not very accurate. On the other hand, the intrinsic uncertainties in the determination of abundances by the ASPCAP pipeline are very small, and therefore we prefer to use chemistry to distinguish the membership of stars in one of the two disk populations. From all the ...
Seeing dark matter in the Andromeda galaxy
... zling that stars far from the center traveled as fast as those much closer to the center. However, we chose not to extend the curve beyond the final measurement by using a decreasing Newtonian inverse square velocity, the common practice at that time. Instead, we wrote “extrapolation beyond that poi ...
... zling that stars far from the center traveled as fast as those much closer to the center. However, we chose not to extend the curve beyond the final measurement by using a decreasing Newtonian inverse square velocity, the common practice at that time. Instead, we wrote “extrapolation beyond that poi ...
Stars: Their Life and Afterlife
... years as a white dwarf, the star’s luminosity has dropped to ~10-4 LŸ and its temperature to ~4000 K. At this point, electrical forces between the constituent ions become important and cause the star’s material to form into a regular lattice – the white dwarf essentially freezes into a solid. Stars ...
... years as a white dwarf, the star’s luminosity has dropped to ~10-4 LŸ and its temperature to ~4000 K. At this point, electrical forces between the constituent ions become important and cause the star’s material to form into a regular lattice – the white dwarf essentially freezes into a solid. Stars ...
MHD_of_Accretion_Disks
... Observing the formation and evolution of circumstellar disks is crucial for understanding the star formation and planet-building processes. If a disk becomes sufficiently massive, compared to the central object that it surrounds, a gravitational instability in the system may cause the disk to accumu ...
... Observing the formation and evolution of circumstellar disks is crucial for understanding the star formation and planet-building processes. If a disk becomes sufficiently massive, compared to the central object that it surrounds, a gravitational instability in the system may cause the disk to accumu ...
Chapter 18 - Origin and Evolution of Stars Chapter Preview
... highly collimated stellar jet. The circumstellar disk eventually dissipates, probably when planets begin to form. Young stars also have dark spots on their surfaces which are analogous to sunspots but cover a much larger fraction of the surface area of the star. The T-Tauri phase is when a star has: ...
... highly collimated stellar jet. The circumstellar disk eventually dissipates, probably when planets begin to form. Young stars also have dark spots on their surfaces which are analogous to sunspots but cover a much larger fraction of the surface area of the star. The T-Tauri phase is when a star has: ...
12C13C1414N21312C/13C3he43He/4He Sub-surface
... is because the opacity is not substantially changing among main sequence models at the same metallicity, such that a higher luminosity renders a larger portion of the envelope convectively unstable (both in radius and mass fraction). Our models show that the FeCZ disappears below a threshold luminos ...
... is because the opacity is not substantially changing among main sequence models at the same metallicity, such that a higher luminosity renders a larger portion of the envelope convectively unstable (both in radius and mass fraction). Our models show that the FeCZ disappears below a threshold luminos ...
Habitable Zone Lifetimes of Exoplanets around Main Sequence Stars
... also possible that CO2 clouds may have the additional effect of reflecting outgoing thermal radiation back to the surface of the planet, contributing to a net warming effect (von Bloh et al., 2007). More-sophisticated climate modeling approaches are required to fully constrain the complex effect tha ...
... also possible that CO2 clouds may have the additional effect of reflecting outgoing thermal radiation back to the surface of the planet, contributing to a net warming effect (von Bloh et al., 2007). More-sophisticated climate modeling approaches are required to fully constrain the complex effect tha ...
Life Cycle of the Stars
... This H–R diagram shows the evolution of stars somewhat more and somewhat less massive than the Sun. The shape of the paths is similar, but they wind up in different places on the main sequence. ...
... This H–R diagram shows the evolution of stars somewhat more and somewhat less massive than the Sun. The shape of the paths is similar, but they wind up in different places on the main sequence. ...
Neon and oxygen in low activity stars: towards a coronal unification
... Our stellar sample consists of those stars from the XMM-Newton monitoring program on coronal activity cycles, i.e. 61 Cyg (K5+K7) (Hempelmann et al. 2006), α Cen (G2+K1) (Robrade et al. 2005, 2007) and HD 81809 (G2+G9) (Favata et al. 2004), as well as the stars β Com (G0), Eri (K2) and Procyon (F5 ...
... Our stellar sample consists of those stars from the XMM-Newton monitoring program on coronal activity cycles, i.e. 61 Cyg (K5+K7) (Hempelmann et al. 2006), α Cen (G2+K1) (Robrade et al. 2005, 2007) and HD 81809 (G2+G9) (Favata et al. 2004), as well as the stars β Com (G0), Eri (K2) and Procyon (F5 ...
Slide 1
... White Dwarf Stars in Clusters • Explore white dwarf cooling ages as compared to main sequence isochrone ages • Open clusters help in establishing ...
... White Dwarf Stars in Clusters • Explore white dwarf cooling ages as compared to main sequence isochrone ages • Open clusters help in establishing ...
Document
... Why is adaptive optics needed? Turbulence in earth’s atmosphere makes stars twinkle More importantly, turbulence spreads out light; makes it a blob rather than a point. This blob is a lot larger than the Point Spread Function (PSF) that would be limited by the size of the telescope only Even the la ...
... Why is adaptive optics needed? Turbulence in earth’s atmosphere makes stars twinkle More importantly, turbulence spreads out light; makes it a blob rather than a point. This blob is a lot larger than the Point Spread Function (PSF) that would be limited by the size of the telescope only Even the la ...
chapter17StarStuff
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses • With each spike, convection dredges carbon up from core and transports it ...
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses • With each spike, convection dredges carbon up from core and transports it ...
Star Formation in Bok Globules - European Southern Observatory
... radiation fram the star is being absorbed in this shell, wh ich reemits it as infrared radiation. Its visual magnitude varies by several tenths of a magnitude in an irregular manner on timescales of days, while its infrared magnitudes have been constant over nearly two years. The luminosity of Serne ...
... radiation fram the star is being absorbed in this shell, wh ich reemits it as infrared radiation. Its visual magnitude varies by several tenths of a magnitude in an irregular manner on timescales of days, while its infrared magnitudes have been constant over nearly two years. The luminosity of Serne ...
Neutron Stars PowerPoint
... – White dwarfs in close binary systems • Gradual mass transfer of H onto the white dwarf’s surface • Highly compressed & heated to ~ 107 K by strong gravity • Runaway surface H fusion is the nova ...
... – White dwarfs in close binary systems • Gradual mass transfer of H onto the white dwarf’s surface • Highly compressed & heated to ~ 107 K by strong gravity • Runaway surface H fusion is the nova ...
galaxies and stars
... less luminous and have a lower surface temperature less luminous and have a higher surface temperature more luminous and have a lower surface temperature more luminous and have a higher surface temperature ...
... less luminous and have a lower surface temperature less luminous and have a higher surface temperature more luminous and have a lower surface temperature more luminous and have a higher surface temperature ...