Article PDF - IOPscience
... the simulations were run with the binary parameters turned off. Since for this study we required detailed information regarding the companion stars and their orbital properties, these were added after the fact as follows. From the TRILEGAL output, we constructed a distance-limited sample with maximu ...
... the simulations were run with the binary parameters turned off. Since for this study we required detailed information regarding the companion stars and their orbital properties, these were added after the fact as follows. From the TRILEGAL output, we constructed a distance-limited sample with maximu ...
Solar Convection Zone
... Fig. 5 shows two volume renderings of the enstrophy density (vorticity squared, jr uj2 ) in a snapshot from a 253 253 163 simulation of the solar surface layers. The renderings each cover a small depth interval, with the rightmost panel corresponding to about 1 Mm larger depth than the leftmost ...
... Fig. 5 shows two volume renderings of the enstrophy density (vorticity squared, jr uj2 ) in a snapshot from a 253 253 163 simulation of the solar surface layers. The renderings each cover a small depth interval, with the rightmost panel corresponding to about 1 Mm larger depth than the leftmost ...
stellar diameters and temperatures. iii. main-sequence a, f, g
... Cousins (RC IC ), Kron (RK IK ), Sloan (griz), and WISE (W3 W4 ) photometric systems. These relations have an average standard deviation of ∼3% and are valid for stars with spectral types A0–M4. To derive even more accurate relations for Sun-like stars, we also determined these temperature relations ...
... Cousins (RC IC ), Kron (RK IK ), Sloan (griz), and WISE (W3 W4 ) photometric systems. These relations have an average standard deviation of ∼3% and are valid for stars with spectral types A0–M4. To derive even more accurate relations for Sun-like stars, we also determined these temperature relations ...
Neutron Degeneracy Pressure
... astrophysics. A vital application is the degeneracy pressure found in the interior of a white dwarf or neutron star. The degeneracy pressure is greatly needed in the interior of these stars to counteract the pressure due to gravity. The balance of the gravitational pressure and degeneracy pressure i ...
... astrophysics. A vital application is the degeneracy pressure found in the interior of a white dwarf or neutron star. The degeneracy pressure is greatly needed in the interior of these stars to counteract the pressure due to gravity. The balance of the gravitational pressure and degeneracy pressure i ...
A CCD Search for Variable Stars of Spectral Type B in the Northern
... appreciably changing the DAO P HOT’s standard deviations of the individual magnitudes. Consequently, the less accurate magnitudes enter the LS analysis with high weight, so that the scatter translates into increased power at low frequencies. Some credibility to this reasoning is lent by the fact tha ...
... appreciably changing the DAO P HOT’s standard deviations of the individual magnitudes. Consequently, the less accurate magnitudes enter the LS analysis with high weight, so that the scatter translates into increased power at low frequencies. Some credibility to this reasoning is lent by the fact tha ...
Hydrodynamic simulations with a radiative surface Atefeh Barekat
... helioseismology that gives insight about some properties of the interior of the Sun. In this technique oscillatory acoustic waves are used to gain information such as temperature and velocities as the differential rotation of the interior of the Sun. For instance, we have an independent verification ...
... helioseismology that gives insight about some properties of the interior of the Sun. In this technique oscillatory acoustic waves are used to gain information such as temperature and velocities as the differential rotation of the interior of the Sun. For instance, we have an independent verification ...
this article
... that LIMS do not explode as supernovae. We cannot understand mass loss fully until we understand the physical nature of the dust. As will be discussed below, interferometric techniques can provide data on evolved LIMS that are essential to understanding dust formation. 2. Stellar evolution LIMS ev ...
... that LIMS do not explode as supernovae. We cannot understand mass loss fully until we understand the physical nature of the dust. As will be discussed below, interferometric techniques can provide data on evolved LIMS that are essential to understanding dust formation. 2. Stellar evolution LIMS ev ...
stars - KIAS
... (Lehmann & Mkrtichian (A&A, submitted) N=970 spectra (R=40,000, S/N~200 ) in 12 nights in October at the 2.0m tel. of TLS Tautenburg. The complete orbital period was covered 3 times, time sampling ~200 sec. Accuracy of of RVs 110 m/s for primary, 1.5 km/sec for secondary: ...
... (Lehmann & Mkrtichian (A&A, submitted) N=970 spectra (R=40,000, S/N~200 ) in 12 nights in October at the 2.0m tel. of TLS Tautenburg. The complete orbital period was covered 3 times, time sampling ~200 sec. Accuracy of of RVs 110 m/s for primary, 1.5 km/sec for secondary: ...
Subrahmanyan Chandrasekhar
... In the years 1929 to 1939, when he was aged 18 to 28, Chandrasekhar was intensely interested in the physics of stars – astrophysics. Traveling by ship in 1930 to begin his Ph.D. at Cambridge University, he had calculated a number. In his honor this number is now called The Chandrasekhar Limit: its v ...
... In the years 1929 to 1939, when he was aged 18 to 28, Chandrasekhar was intensely interested in the physics of stars – astrophysics. Traveling by ship in 1930 to begin his Ph.D. at Cambridge University, he had calculated a number. In his honor this number is now called The Chandrasekhar Limit: its v ...
L25 A NEW CULPRIT IN THE SECOND
... reveal that the red horizontal branch (RHB) stars are strongly concentrated toward the center of the galaxy relative to the dominant old population in Sculptor, confirming an earlier claim of such a gradient. Since we find no radial gradients of the age or metallicity distribution within Sculptor, n ...
... reveal that the red horizontal branch (RHB) stars are strongly concentrated toward the center of the galaxy relative to the dominant old population in Sculptor, confirming an earlier claim of such a gradient. Since we find no radial gradients of the age or metallicity distribution within Sculptor, n ...
Nuclear Astrophysics
... [C/Fe] abundance ratios is what we would expect from CNO1 burning deep down in the star combined with a convective process that is able to dredge CNO processed material up to the atmosphere of the star. For the Li “rich” stars, C is high and N is low. This is not what we expect from CNO1 burning. Th ...
... [C/Fe] abundance ratios is what we would expect from CNO1 burning deep down in the star combined with a convective process that is able to dredge CNO processed material up to the atmosphere of the star. For the Li “rich” stars, C is high and N is low. This is not what we expect from CNO1 burning. Th ...
Self-similarity in the chemical evolution of galaxies and the delay
... cut at MV < 4.75 and on a somewhat less reproducible selection of stars with "a well defined probability function" (H13). H13 note that their absolute age scale could be off by 1 to 1.5 Gyr, while relative ages would have uncertainties of 1 Gyr. The H13 definition of [α/Fe] includes the mean of Mg, ...
... cut at MV < 4.75 and on a somewhat less reproducible selection of stars with "a well defined probability function" (H13). H13 note that their absolute age scale could be off by 1 to 1.5 Gyr, while relative ages would have uncertainties of 1 Gyr. The H13 definition of [α/Fe] includes the mean of Mg, ...
Circumstellar medium around rotating massive stars at solar metallicity
... demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (see Fig. 13 and the discussion in Sect. 4.6). The second new tool is an elaborate, object-oriented implementation of the description of time-dependent stellar boundary conditions for entire stella ...
... demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (see Fig. 13 and the discussion in Sect. 4.6). The second new tool is an elaborate, object-oriented implementation of the description of time-dependent stellar boundary conditions for entire stella ...
High Resolution Observations of Hot Molecular Cores
... Search for the presence of large (cm-size) grains The basic idea is to search for mm spectra that approach the black body spectrum this limiting case is reached only if the disk is optically thick or the ...
... Search for the presence of large (cm-size) grains The basic idea is to search for mm spectra that approach the black body spectrum this limiting case is reached only if the disk is optically thick or the ...
Circum-stellar medium around rotating massive stars at solar
... by stellar winds, for a whole grid of massive stellar models from 15 to 120 M and following the stellar evolution from the zero-age main-sequence to the time of supernova explosion. In addition to the usual quantities, we also follow five chemical species: H, He, C, N, and O. Results. We show how v ...
... by stellar winds, for a whole grid of massive stellar models from 15 to 120 M and following the stellar evolution from the zero-age main-sequence to the time of supernova explosion. In addition to the usual quantities, we also follow five chemical species: H, He, C, N, and O. Results. We show how v ...
Accretion Processes of Binaries of White Dwarfs
... shed a large amount of mass in the form of the slow stellar wind 2. SPH simulations show that steady accretion disk can be formed via gravitational capture of slow stellar wind ...
... shed a large amount of mass in the form of the slow stellar wind 2. SPH simulations show that steady accretion disk can be formed via gravitational capture of slow stellar wind ...
Empirical properties of Very Massive Stars
... ter R136. Their conclusions were based on the results of Massey & Hunter (1998) who obtained masses of about 140–155 M⊙ for the most massive members. We will see later that the most massive members of R136 may actually be more massive than 150 M⊙ , which could slightly change the conclusions of Weid ...
... ter R136. Their conclusions were based on the results of Massey & Hunter (1998) who obtained masses of about 140–155 M⊙ for the most massive members. We will see later that the most massive members of R136 may actually be more massive than 150 M⊙ , which could slightly change the conclusions of Weid ...
RESEARCH STATEMENT Chromospheres and winds
... pulsations strong enough to deliver sufficient acoustic energy to the outer layers of cool stars are also not evident. Magnetic processes such as Alfvén waves are likely a major contributor to winds of dust–free, non–pulsating K and M giant and supergiant stars. However, current magnetic models do ...
... pulsations strong enough to deliver sufficient acoustic energy to the outer layers of cool stars are also not evident. Magnetic processes such as Alfvén waves are likely a major contributor to winds of dust–free, non–pulsating K and M giant and supergiant stars. However, current magnetic models do ...
Population synthesis of Be/white dwarf binaries in the Galaxy
... peaks at 2 104 K for all white dwarfs and at 4 104 K for white dwarfs paired with early-type Be stars (between B0 and B2). The registration of white dwarfs in such systems is hampered by the fact that the entire orbit of a white dwarf is embedded in the dense circumstellar envelope of the primary st ...
... peaks at 2 104 K for all white dwarfs and at 4 104 K for white dwarfs paired with early-type Be stars (between B0 and B2). The registration of white dwarfs in such systems is hampered by the fact that the entire orbit of a white dwarf is embedded in the dense circumstellar envelope of the primary st ...
ISOLATED, MASSIVE SUPERGIANTS NEAR THE GALACTIC
... C iii, N ii, and /or Mg ii (see Morris et al. 1996; Figer et al. 1999). We measured the equivalent widths of the lines by modeling the continuum between 2.1 and 2.4 m as a second-order polynomial and the lines as Gaussians. The equivalent widths also are listed in Table 2. The presence of strong H ...
... C iii, N ii, and /or Mg ii (see Morris et al. 1996; Figer et al. 1999). We measured the equivalent widths of the lines by modeling the continuum between 2.1 and 2.4 m as a second-order polynomial and the lines as Gaussians. The equivalent widths also are listed in Table 2. The presence of strong H ...
THE LUYINOSITY VARIABILITY OF SOLAR
... Galileo, who played a central role in the modern discovery of sunspots, may have wondered whether the Sun varies. Certainly, his 17th century contemporaries did. The Sun itself all but answered this question a few decades later when it nearly stopped forming sunspots as it entered what is now known ...
... Galileo, who played a central role in the modern discovery of sunspots, may have wondered whether the Sun varies. Certainly, his 17th century contemporaries did. The Sun itself all but answered this question a few decades later when it nearly stopped forming sunspots as it entered what is now known ...
Ch. 19 - Astro1010
... Often as a large star ages much of the fuel is used up and deposited as ‘ash’ in the iron core. The inward pressure on the iron core is enormous, due to the high mass of the star. As the core continues to become more and more dense, the protons react with one another to become neutrons + a flood of ...
... Often as a large star ages much of the fuel is used up and deposited as ‘ash’ in the iron core. The inward pressure on the iron core is enormous, due to the high mass of the star. As the core continues to become more and more dense, the protons react with one another to become neutrons + a flood of ...
Detection of isolated population III stars with the James Webb Space
... 1995). This code computes 1D, non-LTE, plane-parallel stellar model atmospheres and spectra, given a certain input stellar composition, surface temperature and gravity. We set the chemical composition of our stars to the primordial mixture of H and He (Iocco et al. 2009). For our models of populatio ...
... 1995). This code computes 1D, non-LTE, plane-parallel stellar model atmospheres and spectra, given a certain input stellar composition, surface temperature and gravity. We set the chemical composition of our stars to the primordial mixture of H and He (Iocco et al. 2009). For our models of populatio ...
THE YELLOW SUPERGIANT PROGENITOR OF THE TYPE II
... have been performed with the QUBA pipeline (Valenti et al. 2011). The photometry were calibrated using a subset of the reference stars presented in Pastorello et al. (2009). Our data are presented in Figure 5, where we compare SN 2011dh to the Type IIb SNe 2008ax (Pastorello et al. 2008; Taubenberge ...
... have been performed with the QUBA pipeline (Valenti et al. 2011). The photometry were calibrated using a subset of the reference stars presented in Pastorello et al. (2009). Our data are presented in Figure 5, where we compare SN 2011dh to the Type IIb SNe 2008ax (Pastorello et al. 2008; Taubenberge ...