1 Introduction - Wiley-VCH
... of galaxies. A typical example is illustrated in Figure 1.5 which shows the image of the interacting system M51 observed at different wavelengths, from the X-ray (Figure 1.5a) to the 21 cm HI radio line (Figure 1.5l). The distribution of the old stellar population, as traced by the near-infrared ima ...
... of galaxies. A typical example is illustrated in Figure 1.5 which shows the image of the interacting system M51 observed at different wavelengths, from the X-ray (Figure 1.5a) to the 21 cm HI radio line (Figure 1.5l). The distribution of the old stellar population, as traced by the near-infrared ima ...
Dust formation in the winds of AGBs: the contribution at low
... convection; this is determined via the classic Schwarzschild criterium, stating that the zone of neutral stability, where buoyancy vanishes, corresponds to the condition ∇ rad = ∇ ad (where ∇ rad and ∇ ad are, respectively the logarithmic temperature gradients when the energy is entirely transported ...
... convection; this is determined via the classic Schwarzschild criterium, stating that the zone of neutral stability, where buoyancy vanishes, corresponds to the condition ∇ rad = ∇ ad (where ∇ rad and ∇ ad are, respectively the logarithmic temperature gradients when the energy is entirely transported ...
Document
... Gaia’s mission is to create the most accurate map of the Galaxy to date. To do this, Gaia is observing about one billion stars, roughly one per cent of the total stellar content of the Milky Way. Eventually, this detailed inventory will include the positions and motions of stars to unprecedented pre ...
... Gaia’s mission is to create the most accurate map of the Galaxy to date. To do this, Gaia is observing about one billion stars, roughly one per cent of the total stellar content of the Milky Way. Eventually, this detailed inventory will include the positions and motions of stars to unprecedented pre ...
Diapositiva 1
... The error depend on the Γ angle (0.5 μas accuracy) Parallactic displacement along the great cicle Sun-Star Sensitivity AL is proportional to sin ξ sin Γ ξ = Sun-spin axis angle = 45º for Gaia Γ = basic angle = 106.5º for Gaia Optimal values between astrometry requirements - that call for a large ang ...
... The error depend on the Γ angle (0.5 μas accuracy) Parallactic displacement along the great cicle Sun-Star Sensitivity AL is proportional to sin ξ sin Γ ξ = Sun-spin axis angle = 45º for Gaia Γ = basic angle = 106.5º for Gaia Optimal values between astrometry requirements - that call for a large ang ...
Ardua et Astra: On the Calculation of the Dates of the Rising and
... dates are precise. When Aujac discusses the disagreements between the dates in the parapegma attached to Geminus’ Isagoge and those in Hofmann’s tables, she raises the possibility that the calculations are wrong, but not that they might have a significant error margin.10 In general it seems that som ...
... dates are precise. When Aujac discusses the disagreements between the dates in the parapegma attached to Geminus’ Isagoge and those in Hofmann’s tables, she raises the possibility that the calculations are wrong, but not that they might have a significant error margin.10 In general it seems that som ...
Finding the Most Distant Quasars Using Bayesian Selection Methods
... been almost completely ionised, as the first generations of stars—and quasars—emitted sufficient ultraviolet radiation to separate electrons from protons. The rest-frame wavelength of the break is at 0.1216 µm, but the wavelength of all light is increased by the cosmological expansion; the Universe ...
... been almost completely ionised, as the first generations of stars—and quasars—emitted sufficient ultraviolet radiation to separate electrons from protons. The rest-frame wavelength of the break is at 0.1216 µm, but the wavelength of all light is increased by the cosmological expansion; the Universe ...
Astrometry of Asteroids
... whose right ascension and declination aren’t known (because it isn’t in a catalog, or because it’s moving from night to night, as a planet or asteroid does), how do we find its coordinates? The answer is that we take a picture of the unknown object, U, and surrounding stars, and then interpolate its ...
... whose right ascension and declination aren’t known (because it isn’t in a catalog, or because it’s moving from night to night, as a planet or asteroid does), how do we find its coordinates? The answer is that we take a picture of the unknown object, U, and surrounding stars, and then interpolate its ...
The Nature of the Stars
... Today, we know that the stars are made of the same chemical elements found on Earth. We know their sizes, their temperatures, their masses, and something of their internal structures. We understand, too, why the stars in the accompanying image come in a range of beautiful colors: Blue stars have hig ...
... Today, we know that the stars are made of the same chemical elements found on Earth. We know their sizes, their temperatures, their masses, and something of their internal structures. We understand, too, why the stars in the accompanying image come in a range of beautiful colors: Blue stars have hig ...
Development of Iodine Cells for the Subaru HDS and the Okayama
... its asymmetry introduces apparent Doppler shifts in the stellar absorption lines. In fact, the precision of our radial velocity measurement was limited to 20 m s−1 or so without such corrections (Takeda et al. 2002). Butler et al. (1996) first outlined such a modeling technique that a star + I2 spec ...
... its asymmetry introduces apparent Doppler shifts in the stellar absorption lines. In fact, the precision of our radial velocity measurement was limited to 20 m s−1 or so without such corrections (Takeda et al. 2002). Butler et al. (1996) first outlined such a modeling technique that a star + I2 spec ...
– 1 – 1. Emission Lines in Nearby Galaxies 1.1.
... To determine the ionization levels of the various elements, one needs to know the electron temperature. The strength of forbidden lines is easy to calculate since they are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in ...
... To determine the ionization levels of the various elements, one needs to know the electron temperature. The strength of forbidden lines is easy to calculate since they are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in ...
Evolution of stars
... 1. The hydrogen lines in spectral type A stars a. are most narrow for supergiants. b. are most narrow for main sequence stars. c. can not be used to estimate the luminosity of the star. d. are very weak and difficult to see. e. are useful in determining the apparent magnitude of the star. 2. Paralla ...
... 1. The hydrogen lines in spectral type A stars a. are most narrow for supergiants. b. are most narrow for main sequence stars. c. can not be used to estimate the luminosity of the star. d. are very weak and difficult to see. e. are useful in determining the apparent magnitude of the star. 2. Paralla ...
STELLAR AGE VERSUS MASS OF EARLY
... performed visually by allowing age steps of 0.05 dex. The age range was then kept fixed for the other colors (middle and bottom panel). We see from the top panel of Fig. 2 that the SSP of HPL07 exceeds the observed color range at intermediate ages. This is no surprise, though: since the reddest colo ...
... performed visually by allowing age steps of 0.05 dex. The age range was then kept fixed for the other colors (middle and bottom panel). We see from the top panel of Fig. 2 that the SSP of HPL07 exceeds the observed color range at intermediate ages. This is no surprise, though: since the reddest colo ...
Lab 14 Galaxy Morphology
... the center. These black holes can have a mass that is a billion times that of the Sun (109 M! )! But not all galaxies have these ferocious beasts at their cores, some merely have large clusters of young stars, while others have a nucleus that is dominated by large numbers of old stars. The Sun orbit ...
... the center. These black holes can have a mass that is a billion times that of the Sun (109 M! )! But not all galaxies have these ferocious beasts at their cores, some merely have large clusters of young stars, while others have a nucleus that is dominated by large numbers of old stars. The Sun orbit ...
SciPoster_Jan2009
... areas of our Galaxy and the Universe, dating all the way back to nearly the beginning of time (e.g., Yan et al. 2005). This dust was formed initially from massive short-lived stars such as Cassiopeia A (e.g., Rho 2008). Dust can also be formed from old, dying stars that used to be like our Sun. Dust ...
... areas of our Galaxy and the Universe, dating all the way back to nearly the beginning of time (e.g., Yan et al. 2005). This dust was formed initially from massive short-lived stars such as Cassiopeia A (e.g., Rho 2008). Dust can also be formed from old, dying stars that used to be like our Sun. Dust ...
Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic
... 1996). Even in the bright prototype Mira system o Cet, the observed X-ray fluxes (∼ 2×1029 erg/sec) cannot be attributed firmly to the AGB star (Soker & Kastner 2003). However, small magnetic fields (few Gauss) have now been shown to be present in the photospheres of evolved red giant stars, with th ...
... 1996). Even in the bright prototype Mira system o Cet, the observed X-ray fluxes (∼ 2×1029 erg/sec) cannot be attributed firmly to the AGB star (Soker & Kastner 2003). However, small magnetic fields (few Gauss) have now been shown to be present in the photospheres of evolved red giant stars, with th ...
Chapter 10 Formation and evolution of the Local Group
... found closer to the Galaxy/M 31 than gas-rich dwarf irregulars (dIrrs). This is often promoted as evidence of environmental processes due to the massive Galaxy and M 31 driving the evolutionary change between dwarf galaxy types. High Velocity Clouds (HVCs) are likely to be either remnant gas left ov ...
... found closer to the Galaxy/M 31 than gas-rich dwarf irregulars (dIrrs). This is often promoted as evidence of environmental processes due to the massive Galaxy and M 31 driving the evolutionary change between dwarf galaxy types. High Velocity Clouds (HVCs) are likely to be either remnant gas left ov ...
Lecture 3 - University of Washington
... Despite 50 years of work, spirals are not very well understood. It seems clear now that the spiral structure of galaxies is a complex problem without any unique and tidy answer. Differential rotation clearly plays a central role, as well as global instabilities, stochastic spirals, and the shocks pa ...
... Despite 50 years of work, spirals are not very well understood. It seems clear now that the spiral structure of galaxies is a complex problem without any unique and tidy answer. Differential rotation clearly plays a central role, as well as global instabilities, stochastic spirals, and the shocks pa ...
Stellar kinematics
Stellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding part of the Milky Way.In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.