BREATHING IN LOW MASS GALAXIES: A STUDY - N
... the fluctuations are strictly periodic, though they would be unlikely to be so in a full cosmological context. The periods of their oscillation are 292, 342, and 387 Myr, respectively. These times are characteristic of the dynamical time of the central region of constant density gas that forms after ...
... the fluctuations are strictly periodic, though they would be unlikely to be so in a full cosmological context. The periods of their oscillation are 292, 342, and 387 Myr, respectively. These times are characteristic of the dynamical time of the central region of constant density gas that forms after ...
Transiting planets from WASP
... evolved. Consequently, they have relatively large radii (R = 1.7−2.1 R ), translating into long (5–6 h) and low-amplitude transits for the three planets: ∼0.6% for WASP-68 b, ∼0.3% for WASP-73 b (the shallowest transits yet for a WASP planet), and ∼0.7% for WASP-88 b. Their detection demonstrates, ...
... evolved. Consequently, they have relatively large radii (R = 1.7−2.1 R ), translating into long (5–6 h) and low-amplitude transits for the three planets: ∼0.6% for WASP-68 b, ∼0.3% for WASP-73 b (the shallowest transits yet for a WASP planet), and ∼0.7% for WASP-88 b. Their detection demonstrates, ...
A Dozen Colliding-Wind X-Ray Binaries in the Star - UvA-DARE
... Large Magellanic Cloud. The image contains 20 X-ray point sources with luminosities between 5 1032 and 2 1035 ergs s1 (0.2–3.5 keV). A dozen sources have bright WN Wolf-Rayet or spectral type O stars as optical counterparts. Nine of these are within 3.4 pc of R136, the central star cluster of ...
... Large Magellanic Cloud. The image contains 20 X-ray point sources with luminosities between 5 1032 and 2 1035 ergs s1 (0.2–3.5 keV). A dozen sources have bright WN Wolf-Rayet or spectral type O stars as optical counterparts. Nine of these are within 3.4 pc of R136, the central star cluster of ...
the Launching of Be-Star Disks
... Before discussing speci c driving mechanisms, it is helpful to review the general requirements for propelling material into orbit from a rotating surface. As re ected in the choice of launch sites for terrestrial satellites, this is easiest when the launch occurs from near the equator and into the d ...
... Before discussing speci c driving mechanisms, it is helpful to review the general requirements for propelling material into orbit from a rotating surface. As re ected in the choice of launch sites for terrestrial satellites, this is easiest when the launch occurs from near the equator and into the d ...
gravitational collapse to black holes
... For both reasons, it is clear that the iron core cannot exist forever, and will collapse under its own weight ...
... For both reasons, it is clear that the iron core cannot exist forever, and will collapse under its own weight ...
Stellar Evolution - Astrophysics
... Define Fλ to be a monochromatic flux per unit area, per unit wavelength interval emergent from the stellar surface; integrating this quantity over all wavelengths gives an integrated flux per unit area which is identical to that of a black body whose temperature is Teff as specified in the first equ ...
... Define Fλ to be a monochromatic flux per unit area, per unit wavelength interval emergent from the stellar surface; integrating this quantity over all wavelengths gives an integrated flux per unit area which is identical to that of a black body whose temperature is Teff as specified in the first equ ...
Jeremy Heyl et al. (PDF document)
... rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution and the timescale for dynamical relaxation are similar. The relaxat ...
... rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution and the timescale for dynamical relaxation are similar. The relaxat ...
Differentially-rotating neutron star models with a parametrized
... our reference value for the onset of secular instability (see discussion at the end of the last paragraph). 2) The mass-shedding limit, which is reached when the angular frequency of matter at the equatorial surface comes close to the local Keplerian frequency and a further spin-up of a star leads t ...
... our reference value for the onset of secular instability (see discussion at the end of the last paragraph). 2) The mass-shedding limit, which is reached when the angular frequency of matter at the equatorial surface comes close to the local Keplerian frequency and a further spin-up of a star leads t ...
Accretion Disk Assembly During Common Envelope Evolution
... net angular momentum relative to the accreting object. Even small gradients thus can have large-scale impacts on the flow, leading to rotational support for material, instead of radial infall as envisioned in HLA. The radial inflow approximation breaks down when the gas reaches a radius Rcirc = lz 2 ...
... net angular momentum relative to the accreting object. Even small gradients thus can have large-scale impacts on the flow, leading to rotational support for material, instead of radial infall as envisioned in HLA. The radial inflow approximation breaks down when the gas reaches a radius Rcirc = lz 2 ...
THE DEARTH OF UV-BRIGHT STARS IN M32
... A LLEN V. S WEIGART, R ANDY A. K IMBLE , C HARLES W. B OWERS Code 667, NASA Goddard Space Flight Center, Greenbelt, MD 20771; [email protected], [email protected], [email protected] Accepted for publication in The Astrophysical Journal ...
... A LLEN V. S WEIGART, R ANDY A. K IMBLE , C HARLES W. B OWERS Code 667, NASA Goddard Space Flight Center, Greenbelt, MD 20771; [email protected], [email protected], [email protected] Accepted for publication in The Astrophysical Journal ...
looking for progenitors of cool Ap stars
... the main-sequence phase, or are intrinsically slow rotators from their formation on. He also found no hint of magnetic braking on the MS from a study of the distribution of the rotation periods as a function of the gravity (North 1985), and this has been confirmed recently on the basis of new surfac ...
... the main-sequence phase, or are intrinsically slow rotators from their formation on. He also found no hint of magnetic braking on the MS from a study of the distribution of the rotation periods as a function of the gravity (North 1985), and this has been confirmed recently on the basis of new surfac ...
Evolution of the barium abundance in the early Galaxy from a NLTE
... levels and overpopulates the upper ones (this “pumping” is described e.g. in Bruls et al. 1992, or Asplund 2005). The depth of the effective formation of the radiation in b-b transitions changes significantly with the metallicity (and the corresponding barium abundance) of the star (Fig. 3). This exp ...
... levels and overpopulates the upper ones (this “pumping” is described e.g. in Bruls et al. 1992, or Asplund 2005). The depth of the effective formation of the radiation in b-b transitions changes significantly with the metallicity (and the corresponding barium abundance) of the star (Fig. 3). This exp ...
Be stars: one ring to rule them all
... In the preceding discussion we did not consider the problem of constructing CE in (or near) Keplerian rotation. Be stars are fast, though under-critical, rotators (Frémat et al. 2005). Comparing the angular momentum per unit mass in a disc at Keplerian rotation J = (GM∗ R)1/2 and at a distance R fr ...
... In the preceding discussion we did not consider the problem of constructing CE in (or near) Keplerian rotation. Be stars are fast, though under-critical, rotators (Frémat et al. 2005). Comparing the angular momentum per unit mass in a disc at Keplerian rotation J = (GM∗ R)1/2 and at a distance R fr ...
KELT-7b: A HOT JUPITER TRANSITING A BRIGHT V = 8.54
... directly predicted by the rotation velocity measured from the spectrum, combined with the transit depth and shape. The RM effect can therefore provide strong confirmation that the transit signal is due to a planetary-sized object transiting the target star. However, for Jupiter-sized companions, this ...
... directly predicted by the rotation velocity measured from the spectrum, combined with the transit depth and shape. The RM effect can therefore provide strong confirmation that the transit signal is due to a planetary-sized object transiting the target star. However, for Jupiter-sized companions, this ...
On the evolution and fate of supermassive stars
... for these stars and confirm the existence of their upper mass limit (≃ 1000 M⊙ ), and study their evolution with mass loss through the core hydrogen and core heliumburning stages. This allows us to determine the mass and nature of the pre-supernova objects and to predict the fate of these objects. T ...
... for these stars and confirm the existence of their upper mass limit (≃ 1000 M⊙ ), and study their evolution with mass loss through the core hydrogen and core heliumburning stages. This allows us to determine the mass and nature of the pre-supernova objects and to predict the fate of these objects. T ...
an approach to effective temperature and surface gravity in post
... SDSS gri photometric systems for main sequence stars. These transformations provide absolute magnitude and distance determinations which can be used in space density evaluations at short distances where some or all of the gri magnitudes are saturated. These authors also showed that those formulae we ...
... SDSS gri photometric systems for main sequence stars. These transformations provide absolute magnitude and distance determinations which can be used in space density evaluations at short distances where some or all of the gri magnitudes are saturated. These authors also showed that those formulae we ...
What powers luminous infrared galaxies?
... 0.1, strongly supporting the notion that an (even moderately extincted) AGN cannot be the main source of their luminosity. The only way out of this important constraint is to postulate that these sources contain AGNs that are hidden even at 15 to 30m, corresponding to AV 50 : : : 200 (N(H2 ) 1 ...
... 0.1, strongly supporting the notion that an (even moderately extincted) AGN cannot be the main source of their luminosity. The only way out of this important constraint is to postulate that these sources contain AGNs that are hidden even at 15 to 30m, corresponding to AV 50 : : : 200 (N(H2 ) 1 ...
Homologous Stars: Simple Scaling Relations
... The case n = 0 corresponds to incompressible fluid, i.e. ρ = ρc = const, P = Pc θ, and it requires rewriting eq. (poly.6) in a different form. In this case pressure vanishes at the surface, but density is the same throughout the ”star”. This solution is a crude approximation to the interior structur ...
... The case n = 0 corresponds to incompressible fluid, i.e. ρ = ρc = const, P = Pc θ, and it requires rewriting eq. (poly.6) in a different form. In this case pressure vanishes at the surface, but density is the same throughout the ”star”. This solution is a crude approximation to the interior structur ...
Carbon Enhanced Stars in the Sloan Digital Sky Survey ( SDSS )
... Now we are ready for the science From the SDSS spectra 1. [C/Fe] versus [Fe/H] 2. [alpha/Fe] versus [Fe/H] 3. s-process and C abundance 4. relative frequency of s-process rich and no n- enrichment How they are distributed in metallicity ...
... Now we are ready for the science From the SDSS spectra 1. [C/Fe] versus [Fe/H] 2. [alpha/Fe] versus [Fe/H] 3. s-process and C abundance 4. relative frequency of s-process rich and no n- enrichment How they are distributed in metallicity ...
Mass segregation in star clusters is not energy equipartition
... profiles. If open clusters formed from initial conditions similar to observed star-forming regions, we therefore would not expect any energy equipartition to occur through dynamical evolution. We repeated the simulations without stellar evolution and find similar results; the most massive stars sink ...
... profiles. If open clusters formed from initial conditions similar to observed star-forming regions, we therefore would not expect any energy equipartition to occur through dynamical evolution. We repeated the simulations without stellar evolution and find similar results; the most massive stars sink ...
Sources of Stellar Energy and the Theory of the Internal Constitution
... inconsistency in the stellar energy problem arises for the reason that the main principles of interaction between matter and radiant energy need to be developed further. Much of the phenomena and empirical correlations discovered by observational astrophysics are linked to the problem of the origin ...
... inconsistency in the stellar energy problem arises for the reason that the main principles of interaction between matter and radiant energy need to be developed further. Much of the phenomena and empirical correlations discovered by observational astrophysics are linked to the problem of the origin ...
Neutron stars - Institut de Physique Nucleaire de Lyon
... nuclei and those of superconducting metal state,” [Phys. Rev. 110 (1958) 936]. A.B.Migdal (1959), V.L.Ginzburg & D.A.Kirzhnits (1964): Tc ~ 1010 K, ρ ~ 1013 – 1015 g/cc. Neutrino emission. H.-Y.Chiu & E.E.Salpeter (1964); J.N.Bahcall & R.A.Wolf ...
... nuclei and those of superconducting metal state,” [Phys. Rev. 110 (1958) 936]. A.B.Migdal (1959), V.L.Ginzburg & D.A.Kirzhnits (1964): Tc ~ 1010 K, ρ ~ 1013 – 1015 g/cc. Neutrino emission. H.-Y.Chiu & E.E.Salpeter (1964); J.N.Bahcall & R.A.Wolf ...
Chapter 12 Pre-supernova evolution of massive stars
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached in these stars is smaller than the temperature required for carbon fusion. During the lates ...
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached in these stars is smaller than the temperature required for carbon fusion. During the lates ...
Astrophysics in a Nutshell, Second Edition
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Stars with higher initial ...
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Stars with higher initial ...
Pulsar slow glitches in a solid quark star model
... in the star-quake model of quark stars, in order to have an effective small shear modulus. Soon after a quake, we assume that a superficial layer moves in order to set a new equilibrium (see Fig. 2), while most of the inner part of star keeps almost the same. Part of the energy released turns into h ...
... in the star-quake model of quark stars, in order to have an effective small shear modulus. Soon after a quake, we assume that a superficial layer moves in order to set a new equilibrium (see Fig. 2), while most of the inner part of star keeps almost the same. Part of the energy released turns into h ...