Formation of spiral and elliptical galaxies in a CDM cosmogony
... frame: Position of gas particles which will form old and metal rich (bulge) stars. Right frame: Position of gas particles which will form old and metal poor (halo) stars. formed in the main maximum of the primordial uctuation eld. On the other hand gas particles, which end up in old and metal poor ...
... frame: Position of gas particles which will form old and metal rich (bulge) stars. Right frame: Position of gas particles which will form old and metal poor (halo) stars. formed in the main maximum of the primordial uctuation eld. On the other hand gas particles, which end up in old and metal poor ...
REVIEWS The formation of the first stars and galaxies Volker Bromm
... which posits that structure grew hierarchically, such that small objects formed first and then merged to form increasingly larger systems6. Within this model, dark-matter ‘minihaloes’ (see below), forming a few hundred million years after the Big Bang, were identified as the sites where the first st ...
... which posits that structure grew hierarchically, such that small objects formed first and then merged to form increasingly larger systems6. Within this model, dark-matter ‘minihaloes’ (see below), forming a few hundred million years after the Big Bang, were identified as the sites where the first st ...
The Sagittarius dwarf irregular galaxy: Metallicity and stellar
... presents color-magnitude diagram in different colors, using a statistical correction of the foreground contamination. The CMD location of C stars is also discussed. In Sect. 4 we rederive the distance and metallicity of SagDIG by assuming a different reddening for the young and old populations. The ...
... presents color-magnitude diagram in different colors, using a statistical correction of the foreground contamination. The CMD location of C stars is also discussed. In Sect. 4 we rederive the distance and metallicity of SagDIG by assuming a different reddening for the young and old populations. The ...
Chapter 5 Energy transport in stellar interiors
... small (typically ℓph ∼ 1 cm ≪ R⊙ , see Sect. 3.1). As a result, radiation is trapped within the stellar interior, and photons diffuse outwards very slowly by a ‘random walk’ process. The time it takes radiation to escape from the centre of the Sun by this random walk process is roughly 107 years, de ...
... small (typically ℓph ∼ 1 cm ≪ R⊙ , see Sect. 3.1). As a result, radiation is trapped within the stellar interior, and photons diffuse outwards very slowly by a ‘random walk’ process. The time it takes radiation to escape from the centre of the Sun by this random walk process is roughly 107 years, de ...
the opportunities and challenges for astrometry in the 21st century
... field of the cluster we can identify stars not moving with the motion of the cluster using techniques described, for example, by Vasilevskis, Klemola, & Preston (1958) and Platais et al. (2003). In the past it was necessary to wait 20 to 30 years after the first-epoch plates were taken to repeat the ...
... field of the cluster we can identify stars not moving with the motion of the cluster using techniques described, for example, by Vasilevskis, Klemola, & Preston (1958) and Platais et al. (2003). In the past it was necessary to wait 20 to 30 years after the first-epoch plates were taken to repeat the ...
High Energy Phenomena in Supergiant X-ray Binaries - HAL-Insu
... IGR J16318-4848, an extreme case IGR J16318-4848 was the first source discovered by IBIS/ISGRI on INTEGRAL on 29 January 2003 (Courvoisier et al. 2003), with a 2′ uncertainty. XMM-Newton observations revealed a comptonised spectrum exhibiting an unusually high level of absorption: NH ∼ 1.84 × 1024 c ...
... IGR J16318-4848, an extreme case IGR J16318-4848 was the first source discovered by IBIS/ISGRI on INTEGRAL on 29 January 2003 (Courvoisier et al. 2003), with a 2′ uncertainty. XMM-Newton observations revealed a comptonised spectrum exhibiting an unusually high level of absorption: NH ∼ 1.84 × 1024 c ...
Chapter 9 Early stages of evolution and the main sequence phase
... Therefore the shape of the Hayashi line in the HRD is determined by how the opacity in the photosphere depends on ρ and T . Since fully convective stars have very cool photospheres, the opacity is mainly given by H− absorption (Sect. 5.3) which increases strongly with temperature. According to eq. ( ...
... Therefore the shape of the Hayashi line in the HRD is determined by how the opacity in the photosphere depends on ρ and T . Since fully convective stars have very cool photospheres, the opacity is mainly given by H− absorption (Sect. 5.3) which increases strongly with temperature. According to eq. ( ...
IDENTIFICATION OF MAIN-SEQUENCE STARS WITH MID
... the observed spectral types (De Jager & Nieuwenhuijzen 1987; Schmidt-Kaler 1982; Johnson 1966), we calculated a spectrophotometric distance to each star. These distances and their uncertainties, estimated by taking into account the K-band photometric errors added in quadrature with an additional 15% ...
... the observed spectral types (De Jager & Nieuwenhuijzen 1987; Schmidt-Kaler 1982; Johnson 1966), we calculated a spectrophotometric distance to each star. These distances and their uncertainties, estimated by taking into account the K-band photometric errors added in quadrature with an additional 15% ...
3. Measuring Distances and Magnitudes
... Telescope) have improved parallax accuracy to 0.001” within a few years. Prior to 1990, less than 10,000 stellar parallaxes had been measured (and only 500 known well), but there are about 1012 stars in our Galaxy. Space observations made by the European Space Agency with the Hipparcos mission (1989 ...
... Telescope) have improved parallax accuracy to 0.001” within a few years. Prior to 1990, less than 10,000 stellar parallaxes had been measured (and only 500 known well), but there are about 1012 stars in our Galaxy. Space observations made by the European Space Agency with the Hipparcos mission (1989 ...
Process of Science: PreMainSequence Stellar Life Tracks on the HR
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
The LMC transition star R84 and the core of the LH 39 OB association
... other hand, the SUSI CCD produced some non-Gaussian noise in the images but at a very low level, negligible at the S/N ratio of the stars studied here. Since R 84 is a very bright object, it was not always possible to avoid saturation, especially on our good seeing observations. These are the SUSI R ...
... other hand, the SUSI CCD produced some non-Gaussian noise in the images but at a very low level, negligible at the S/N ratio of the stars studied here. Since R 84 is a very bright object, it was not always possible to avoid saturation, especially on our good seeing observations. These are the SUSI R ...
The Kinematics of Star Formation: Theory and Observation in the
... of the cluster are able to accrete more mass because of their location at the deepest point in the cluster potential. These cores are therefore more likely to grow to become the most massive stars in the cluster. Competitive accretion therefore predicts that the most massive stars should form at th ...
... of the cluster are able to accrete more mass because of their location at the deepest point in the cluster potential. These cores are therefore more likely to grow to become the most massive stars in the cluster. Competitive accretion therefore predicts that the most massive stars should form at th ...
The End of the Dark Ages
... larger in the L20 run because of the higher ionizing power of the sources. Their shape, particularly for larger ones, appears distorted by nearby high density peaks. (To a good approximation these correspond to peaks in the HI distribution.) The ionization front slows when it encounter such overdens ...
... larger in the L20 run because of the higher ionizing power of the sources. Their shape, particularly for larger ones, appears distorted by nearby high density peaks. (To a good approximation these correspond to peaks in the HI distribution.) The ionization front slows when it encounter such overdens ...
Observations with Herschel: High-mass star formation and the
... At the same time as the ISM is the birthplace of stars and planets, the bright stars regulate the structure, composition and chemical evolution of the ISM, thus influencing the star formation rate and galactic evolution. In a cyclic process, gas and dust clouds collapse gravitationally to form stars ...
... At the same time as the ISM is the birthplace of stars and planets, the bright stars regulate the structure, composition and chemical evolution of the ISM, thus influencing the star formation rate and galactic evolution. In a cyclic process, gas and dust clouds collapse gravitationally to form stars ...
2P10.pdf
... The scientific goals of the Gaia mission require complementary astrometry, photometry and radial velocity data. After five years scanning the entire sky, Gaia will have performed measurements with broad (BBP), and medium (MBP) bands, and white light (G magnitude). The main goal of the photometry is ...
... The scientific goals of the Gaia mission require complementary astrometry, photometry and radial velocity data. After five years scanning the entire sky, Gaia will have performed measurements with broad (BBP), and medium (MBP) bands, and white light (G magnitude). The main goal of the photometry is ...
Figure 1. Map showing the region of the Fourth Quadrant selected
... in these denser clumps (leading to short lifetimes before collapse). Furthermore, the frequent disruption of clouds by turbulence (preventing collapse in many clumps) can account for the low observed star formation efficiency, which is ultimately set by the rate and characteristic scale of the energ ...
... in these denser clumps (leading to short lifetimes before collapse). Furthermore, the frequent disruption of clouds by turbulence (preventing collapse in many clumps) can account for the low observed star formation efficiency, which is ultimately set by the rate and characteristic scale of the energ ...
Introduc on to the Fundamental Astrophysics Course
... Being more specific … Stellar Evolu)on • Stellar evolu)on is the process by which a star undergoes a sequence of radical changes during its life)me. • Depending on the mass of the star, this lif ...
... Being more specific … Stellar Evolu)on • Stellar evolu)on is the process by which a star undergoes a sequence of radical changes during its life)me. • Depending on the mass of the star, this lif ...
LesHouches_VanGrootel
... The Extreme Horizontal Branch (EHB) stars Hot (Teff ~ 30 000 K) and compact stars (log g ~ 5.5) belonging to Extreme Horizontal Branch (EHB), an intermediate stage of evolution Internal structure: ...
... The Extreme Horizontal Branch (EHB) stars Hot (Teff ~ 30 000 K) and compact stars (log g ~ 5.5) belonging to Extreme Horizontal Branch (EHB), an intermediate stage of evolution Internal structure: ...
The discovery based on GLIMPSE data of a protostar driving a
... Lada (1987) developed a widely used classification scheme for YSOs primarily based on their spectral energy distributions (SEDs) and the spectral index at the infrared. With an evolutionary sequence from early to late type, YSOs were classified into Class I to III (Lada 1987). Later on, an earlier e ...
... Lada (1987) developed a widely used classification scheme for YSOs primarily based on their spectral energy distributions (SEDs) and the spectral index at the infrared. With an evolutionary sequence from early to late type, YSOs were classified into Class I to III (Lada 1987). Later on, an earlier e ...
ppt - CIERA - Northwestern
... of galactic orbital periods and 10% or less of massive star evolutionary time scales. ...
... of galactic orbital periods and 10% or less of massive star evolutionary time scales. ...
HST Paα Survey of the Galactic Center – Seeking the Missing
... within the GC, compared to previous observations. We find 152 Paα emitting sources, which are evolved massive stars. Half of them are located outside of three young massive star clusters near Sgr A*. The spatial distribution of these field sources suggests that they are within less massive star clus ...
... within the GC, compared to previous observations. We find 152 Paα emitting sources, which are evolved massive stars. Half of them are located outside of three young massive star clusters near Sgr A*. The spatial distribution of these field sources suggests that they are within less massive star clus ...
Ultra faint dwarfs: probing early cosmic star formation
... rate depressed in these systems by the scarce availability of gas, mechanical feedback has negligible effects, and they evolve as a closed-box. As essentially all metals are retained they have a relatively high Fe-abundance which is seen as an almost inverted Fe-L relation below L = 104.5 L⊙ . Secon ...
... rate depressed in these systems by the scarce availability of gas, mechanical feedback has negligible effects, and they evolve as a closed-box. As essentially all metals are retained they have a relatively high Fe-abundance which is seen as an almost inverted Fe-L relation below L = 104.5 L⊙ . Secon ...
Article PDF - IOPscience
... Russell diagram as compared to the theoretical tracks. The errors on the stellar mass are dominated by the uncertainty on the metallicity. Here, we take into account uncertainties on the stellar temperature, metallicity, and density. We do not include systematic uncertainties on the chosen stellar m ...
... Russell diagram as compared to the theoretical tracks. The errors on the stellar mass are dominated by the uncertainty on the metallicity. Here, we take into account uncertainties on the stellar temperature, metallicity, and density. We do not include systematic uncertainties on the chosen stellar m ...
molecular observations of H CO , 13CO, HCN how to determine
... density. The stellar positions are from Kenyon (2007). The diamonds indicate diffuse or extended sources (of which there are 44 in the region mapped), the squares indicate Class I or younger stars (18), and the asterisks indicate T-Tauri stars (168). It is evident that the ...
... density. The stellar positions are from Kenyon (2007). The diamonds indicate diffuse or extended sources (of which there are 44 in the region mapped), the squares indicate Class I or younger stars (18), and the asterisks indicate T-Tauri stars (168). It is evident that the ...
The X-ray Bursters Problem and its Implications to the Equation of
... density) (9). The Tolman-Oppenheimer-Volkov (TOV) relativistic stellar structure equations describes the extremely dense cold matter in their cores by relating pressure and energy density (the equation of state, EoS hereafter). There is a unique map between the microscopic pressure-density relation ...
... density) (9). The Tolman-Oppenheimer-Volkov (TOV) relativistic stellar structure equations describes the extremely dense cold matter in their cores by relating pressure and energy density (the equation of state, EoS hereafter). There is a unique map between the microscopic pressure-density relation ...