as a PDF
... classical T-Tauri Stars (cTTSs), measured by millimeter continuum observations, preclude a simple spherical distribution of the circumstellar material about such stars (Rydgren et al. 1982). The mass involved would, if spherically distributed, yield much higher optical extinctions than are actually ...
... classical T-Tauri Stars (cTTSs), measured by millimeter continuum observations, preclude a simple spherical distribution of the circumstellar material about such stars (Rydgren et al. 1982). The mass involved would, if spherically distributed, yield much higher optical extinctions than are actually ...
The (galaxy-wide) IMF in giant elliptical galaxies: from top to bottom
... Accepted 2013 August 1. Received 2013 July 30; in original form 2013 June 12 ...
... Accepted 2013 August 1. Received 2013 July 30; in original form 2013 June 12 ...
stellar rotation in m35: mass–period relations, spin
... young main-sequence clusters, Barnes (2003) presented an interpretation of his own and other published rotation period data. Free of the ambiguities of v sin(i), Barnes identified, in each coeval stellar population, separate groups of fast and intermediate/ slowly rotating stars with different depen ...
... young main-sequence clusters, Barnes (2003) presented an interpretation of his own and other published rotation period data. Free of the ambiguities of v sin(i), Barnes identified, in each coeval stellar population, separate groups of fast and intermediate/ slowly rotating stars with different depen ...
The effect of starspots on the radii of low-mass
... an empirical radius–luminosity relation for inactive MS stars (e.g. from BM12). SW86 estimated the effect of starspots only for ZAMS stars, where the luminosity depends on the temperature of their nuclear burning cores. The cool M-dwarfs in NGC 2516, which show the largest apparent increase in radiu ...
... an empirical radius–luminosity relation for inactive MS stars (e.g. from BM12). SW86 estimated the effect of starspots only for ZAMS stars, where the luminosity depends on the temperature of their nuclear burning cores. The cool M-dwarfs in NGC 2516, which show the largest apparent increase in radiu ...
Polaris B, an optical companion of Polaris (alpha UMi) system
... potential members of the multiple system (Fernie, 1966), although recent observations refute that suggestion (Evans et al., 2007). It would therefore be interesting to establish the atmospheric parameters and chemical composition of component B for comparison with those for the Cepheid Polaris itsel ...
... potential members of the multiple system (Fernie, 1966), although recent observations refute that suggestion (Evans et al., 2007). It would therefore be interesting to establish the atmospheric parameters and chemical composition of component B for comparison with those for the Cepheid Polaris itsel ...
Astronomy 112: The Physics of Stars Class 1 Notes
... extended mnemonic Oh Be A Fine Girl/guy, Kiss Me Like That, which proves one thing – astronomers have way too much time on their hands. There has been a theoretical proposal that a new type of spectral class should appear for objects even dimmer than T dwarfs, although no examples of such an object ...
... extended mnemonic Oh Be A Fine Girl/guy, Kiss Me Like That, which proves one thing – astronomers have way too much time on their hands. There has been a theoretical proposal that a new type of spectral class should appear for objects even dimmer than T dwarfs, although no examples of such an object ...
STELLAR STRUCTURE AND EVOLUTION
... An important implication of this definition is that stars must evolve (why?). A star is born out of an interstellar (molecular) gas cloud, lives for a certain amount of time on its internal energy supply, and eventually dies when this supply is exhausted. As we shall see, a second implication of the ...
... An important implication of this definition is that stars must evolve (why?). A star is born out of an interstellar (molecular) gas cloud, lives for a certain amount of time on its internal energy supply, and eventually dies when this supply is exhausted. As we shall see, a second implication of the ...
The physics of neutron stars
... the mass M ∼ M⊙ have the radius R ∼ 104 km, which is comparable to Earth’s radius but almost 1000 times greater than the radius of a neutron star [3]. Therefore, the matter density in their interiors is less than one-thousandth of ρ0 . On the other hand, according to theoretical models, quark stars ...
... the mass M ∼ M⊙ have the radius R ∼ 104 km, which is comparable to Earth’s radius but almost 1000 times greater than the radius of a neutron star [3]. Therefore, the matter density in their interiors is less than one-thousandth of ρ0 . On the other hand, according to theoretical models, quark stars ...
Physical Properties of Wolf-Rayet Stars
... In particular, Wolf-Rayet (WR) stars typically have wind densities an order of magnitude higher than massive O stars. They contribute to the chemical enrichment of galaxies, they are the prime candidates for the immediate progenitors of long, soft gamma-ray bursts (GRBs, Woosley & Bloom 2006), and t ...
... In particular, Wolf-Rayet (WR) stars typically have wind densities an order of magnitude higher than massive O stars. They contribute to the chemical enrichment of galaxies, they are the prime candidates for the immediate progenitors of long, soft gamma-ray bursts (GRBs, Woosley & Bloom 2006), and t ...
Near-uniform internal rotation of the main sequence γ Doradus
... attributed to rotation, contrary to previous suggestions concerning the origin of such signals. Key words: asteroseismology – stars: individual: KIC 7660154 – stars: oscillations – stars: rotation – techniques: spectroscopic ...
... attributed to rotation, contrary to previous suggestions concerning the origin of such signals. Key words: asteroseismology – stars: individual: KIC 7660154 – stars: oscillations – stars: rotation – techniques: spectroscopic ...
(n,γ) x-sections of 63 Ni
... evolution and nucleosynthesis. n_TOF offers the best conditions to obtain these nuclear physics quantities with the required accuracy. The n_TOF Collaboration is carrying on an extensive plan to measure cross sections relevant for nuclear astrophysics, in particular for s-process nucleosynthesis stu ...
... evolution and nucleosynthesis. n_TOF offers the best conditions to obtain these nuclear physics quantities with the required accuracy. The n_TOF Collaboration is carrying on an extensive plan to measure cross sections relevant for nuclear astrophysics, in particular for s-process nucleosynthesis stu ...
Measuring Reddening with SDSS Stellar Spectra and Recalibrating
... colors is used as a measurement of reddening to each star. These reddening measurements are then used to test the calibration of SFD and the reddening law. We test the calibration of SFD and the reddening law by comparing our reddening measurements with the predictions from SFD and a reddening law. ...
... colors is used as a measurement of reddening to each star. These reddening measurements are then used to test the calibration of SFD and the reddening law. We test the calibration of SFD and the reddening law by comparing our reddening measurements with the predictions from SFD and a reddening law. ...
The rebirth of Supernova 1987A a study of the ejecta-ring collision
... SNe. The first type (Type I) shows no hydrogen emission lines, whereas the second type (Type II) has prominent hydrogen lines. Baade & Zwicky were also the first ones to suggest that SNe were results of the great energy release of collapsing stars (Baade & Zwicky 1934). The idea of the collapsing co ...
... SNe. The first type (Type I) shows no hydrogen emission lines, whereas the second type (Type II) has prominent hydrogen lines. Baade & Zwicky were also the first ones to suggest that SNe were results of the great energy release of collapsing stars (Baade & Zwicky 1934). The idea of the collapsing co ...
An atlas of 2.4 to 4.1 mu m ISO/SWS spectra of early - UvA-DARE
... (SWS) during the Post-Helium program of the Infrared Space Observatory (ISO). This program is aimed at extending the Morgan & Keenan classification scheme into the near-infrared. Later type stars will be discussed in a separate publication. The observations consist of 57 SWS Post-Helium spectra from ...
... (SWS) during the Post-Helium program of the Infrared Space Observatory (ISO). This program is aimed at extending the Morgan & Keenan classification scheme into the near-infrared. Later type stars will be discussed in a separate publication. The observations consist of 57 SWS Post-Helium spectra from ...
Jaká kritéria jsou vhodná ke klasifikaci hvězd horní části hlavní
... Spectroscopy today is a highly developed method of studying electromagnetic radiation and stands as method bringing a vast amount of information about distant objects to us. Product of a spectroscopic measurement is called a spectrum and it is essentially a function of distribution of radiation resp ...
... Spectroscopy today is a highly developed method of studying electromagnetic radiation and stands as method bringing a vast amount of information about distant objects to us. Product of a spectroscopic measurement is called a spectrum and it is essentially a function of distribution of radiation resp ...
they might be giants: luminosity class, planet occurrence, and planet
... those planets is higher. For M dwarf stars in general, and particularly for the coolest Kepler target stars, parameters such as radius are uncertain or even very unreliable (e.g. Johnson et al. 2012, M11). Brown et al. (2011) metallicities are reliable to 0.4 dex for solar-type stars, but are essent ...
... those planets is higher. For M dwarf stars in general, and particularly for the coolest Kepler target stars, parameters such as radius are uncertain or even very unreliable (e.g. Johnson et al. 2012, M11). Brown et al. (2011) metallicities are reliable to 0.4 dex for solar-type stars, but are essent ...
They might be giants: luminosity class, planet frequency, and planet
... catalog and the M2K Doppler survey could be achieved if the former was incomplete compared to estimates based on KIC radii. They further point out that Kepler planet candidates were conspicuously sparse among late K stars with colors that are shared by both dwarfs and giant stars. Finally, Muirhead ...
... catalog and the M2K Doppler survey could be achieved if the former was incomplete compared to estimates based on KIC radii. They further point out that Kepler planet candidates were conspicuously sparse among late K stars with colors that are shared by both dwarfs and giant stars. Finally, Muirhead ...
Numerical Star-Formation Studies-
... Today we also know that many stars harbor planetary systems around them, about 300 are known as of fall 2008 (Udry and Santos, 2007). The build-up of planets is intimately coupled to the formation of their host stars. Understanding the origin of our solar system and of planets around other stars has ...
... Today we also know that many stars harbor planetary systems around them, about 300 are known as of fall 2008 (Udry and Santos, 2007). The build-up of planets is intimately coupled to the formation of their host stars. Understanding the origin of our solar system and of planets around other stars has ...
Annual Report 2012 - Max Planck Institute for Astrophysics
... quickly repaired by a complete exchange of the computer. In addition to the desktop systems, which, in large part are younger than 5 years and which (in 2012) amount to more than 170 fully equipped working places, users have access to central number crunchers (about 20 machines, all 64-bit architect ...
... quickly repaired by a complete exchange of the computer. In addition to the desktop systems, which, in large part are younger than 5 years and which (in 2012) amount to more than 170 fully equipped working places, users have access to central number crunchers (about 20 machines, all 64-bit architect ...
Chapter 1
... ratios are higher than a cooler nebula. This is because to produce [O iii] λ4363 an electron needs to be excited to 5.3 eV, which requires more energy than for 4959/5007 which result from decay from 1 D2 level, 2.5 eV above the ground-state (see Figure 2.2). Therefore, these ratios can be used to co ...
... ratios are higher than a cooler nebula. This is because to produce [O iii] λ4363 an electron needs to be excited to 5.3 eV, which requires more energy than for 4959/5007 which result from decay from 1 D2 level, 2.5 eV above the ground-state (see Figure 2.2). Therefore, these ratios can be used to co ...
Chapter 7 in the LSST Science Book
... interpretation of local data within a larger context: the stars that make galaxies are expected to form within dark matter halos that are themselves growing through gravitational collapse and mergers. In fact, we are very fortunate to live in a hierarchical Universe where the LV galaxies contain the ...
... interpretation of local data within a larger context: the stars that make galaxies are expected to form within dark matter halos that are themselves growing through gravitational collapse and mergers. In fact, we are very fortunate to live in a hierarchical Universe where the LV galaxies contain the ...
THE ORION NEBULA AND ITS ASSOCIATED POPULATION C. R. O
... makes it one of the most famous celestial objects and the subject of investigation by almost every new type of observation. This pattern has held true since the advent of the first optical telescopes through today’s X-ray observatories. It is no surprise, therefore, that we know more about this one ...
... makes it one of the most famous celestial objects and the subject of investigation by almost every new type of observation. This pattern has held true since the advent of the first optical telescopes through today’s X-ray observatories. It is no surprise, therefore, that we know more about this one ...
Classical Oe Stars in the Field of the Small Magellanic Cloud
... However, gravitational limb darkening may cause these rotational rates to be underestimated (e.g., Stoeckley 1968; Townsend et al. 2004; Frémat et al. 2005), thus suggesting that Be stars may rotate closer to vcrit than observations find. Determining how Be stars form with subcritical rotation rate ...
... However, gravitational limb darkening may cause these rotational rates to be underestimated (e.g., Stoeckley 1968; Townsend et al. 2004; Frémat et al. 2005), thus suggesting that Be stars may rotate closer to vcrit than observations find. Determining how Be stars form with subcritical rotation rate ...
Runaway collisions in young star clusters – II. Numerical results
... It is important to stress, however, that our MC simulations probe a different regime from that explored by the direct N-body approach. We consider systems with higher number of stars in the central region (inside a few core radii). For this reason, some of our most important results are only superfi ...
... It is important to stress, however, that our MC simulations probe a different regime from that explored by the direct N-body approach. We consider systems with higher number of stars in the central region (inside a few core radii). For this reason, some of our most important results are only superfi ...
Finding high-redshift dark stars with the James Webb Space
... fusion processes eventually take over as the dominant power source if the dark matter is not replenished. At this point, the dark star will essentially transform into a conventional population III star, albeit more massive because the increased duration of the formation phase has allowed it to accre ...
... fusion processes eventually take over as the dominant power source if the dark matter is not replenished. At this point, the dark star will essentially transform into a conventional population III star, albeit more massive because the increased duration of the formation phase has allowed it to accre ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.