Gravitational-wave signal from binary neutron star merger
... short gamma ray bursts [15–18], even if the exact mechanism for their emission is still investigated with astrophysical modelling and numerical simulations [19–28]. Other EM emissions, both in the coalescent phase (before the merger, from the interaction of the stars magnetosphere [29, 30]), and in ...
... short gamma ray bursts [15–18], even if the exact mechanism for their emission is still investigated with astrophysical modelling and numerical simulations [19–28]. Other EM emissions, both in the coalescent phase (before the merger, from the interaction of the stars magnetosphere [29, 30]), and in ...
The old Nuclear Star Cluster in the Milky Way
... Histogram of the extinction AK based on H − K colors for all the stars. . . Average differential extinction of nuclear cluster stars plotted as a function of υl and υb proper motion. . . . . . . . . . . . . . . . . . . . . . . . . . . Extinction derived from the observed ratio of Paα to H92α radio r ...
... Histogram of the extinction AK based on H − K colors for all the stars. . . Average differential extinction of nuclear cluster stars plotted as a function of υl and υb proper motion. . . . . . . . . . . . . . . . . . . . . . . . . . . Extinction derived from the observed ratio of Paα to H92α radio r ...
THE CHEMICAL COMPOSITION AND AGE OF THE METAL
... throughout the Galaxy’s history (see Wheeler, Sneden, & Truran 1989 and references therein). Thus, while barium appears to be synthesized by the r-process at earliest times, this element is predominantly produced in solar system material by the s-process (see B00) in low- to intermediatemass stars ( ...
... throughout the Galaxy’s history (see Wheeler, Sneden, & Truran 1989 and references therein). Thus, while barium appears to be synthesized by the r-process at earliest times, this element is predominantly produced in solar system material by the s-process (see B00) in low- to intermediatemass stars ( ...
Studies of dark matter in and around stars
... There is by now compelling evidence that most of the matter in the Universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is ...
... There is by now compelling evidence that most of the matter in the Universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is ...
ppt - ciera
... 1-2 : A more massive MS star exchanges into a MS-MS binary 3 : the primary evolves off the MS and fills its Roche lobe 4: the secondary gains mass from the primary becoming a BSS ...
... 1-2 : A more massive MS star exchanges into a MS-MS binary 3 : the primary evolves off the MS and fills its Roche lobe 4: the secondary gains mass from the primary becoming a BSS ...
astro-ph/9808039 PDF
... the optical fluxes reported in Paper I were a factor of 1.7 too high, because an incorrect aperture diameter was applied to the Hii region HK11 (Kennicutt 1988), whose Hα flux was the calibration standard. The corrected calibration of the GAFPIC data has been confirmed by comparison to another study ...
... the optical fluxes reported in Paper I were a factor of 1.7 too high, because an incorrect aperture diameter was applied to the Hii region HK11 (Kennicutt 1988), whose Hα flux was the calibration standard. The corrected calibration of the GAFPIC data has been confirmed by comparison to another study ...
Chemical gradients in the Milky Way from the RAVE data
... helps minimising these differences, which should not affect the results on the abundance gradients significantly. In fact, although the spectrum quality parameters change as a function of the distance (because RAVE is a magnitude-limited survey with constant integration time, more distant stars have o ...
... helps minimising these differences, which should not affect the results on the abundance gradients significantly. In fact, although the spectrum quality parameters change as a function of the distance (because RAVE is a magnitude-limited survey with constant integration time, more distant stars have o ...
Models of the Structure and Evolution of Protoplanetary Disks
... we will show in Section 3, most of the disk is ‘irradiationdominated’, and consequently has temperature given approximately by Tc ∼ r−1/2 . This results in the surface density going as Σ ∼ r−1 . This surface density distribution is less steep than the so-called “minimum mass solar nebula” (MMSN), gi ...
... we will show in Section 3, most of the disk is ‘irradiationdominated’, and consequently has temperature given approximately by Tc ∼ r−1/2 . This results in the surface density going as Σ ∼ r−1 . This surface density distribution is less steep than the so-called “minimum mass solar nebula” (MMSN), gi ...
Fundamental properties of Ana González Galán
... The discovery of the first extra-solar X-ray source [Sco X-1; Giacconi et al., 1962] constituted the beginning of X-ray astronomy. Since then, the interest and discoveries related to X/γ-ray astronomy has grown thanks to the ability to send X-ray space missions above the Earth’s atmosphere with more ...
... The discovery of the first extra-solar X-ray source [Sco X-1; Giacconi et al., 1962] constituted the beginning of X-ray astronomy. Since then, the interest and discoveries related to X/γ-ray astronomy has grown thanks to the ability to send X-ray space missions above the Earth’s atmosphere with more ...
Debris disks: seeing dust, thinking of planetesimals and planets
... mt mp where mt and mp are masses of the p two colliders. Thus two like-sized objects will be destroyed if they collide at a speed exceeding 8Q?D . For two dust grains, the critical speed is several hundred m s−1 . At several tens of AU from a star, this would imply eccentricities of ∼ 0.1 or higher. ...
... mt mp where mt and mp are masses of the p two colliders. Thus two like-sized objects will be destroyed if they collide at a speed exceeding 8Q?D . For two dust grains, the critical speed is several hundred m s−1 . At several tens of AU from a star, this would imply eccentricities of ∼ 0.1 or higher. ...
CENTRAL STARS OF PLANETARY NEBULAE IN THE LARGE
... wind signatures. SMP LMC 62 has questionable O vi wind features, and its UV lines are contaminated by nebular emission features. The FUSE spectrum of SMP LMC 35, the dimmest object, has the lowest S/ N and is not of sufficient quality to make a definitive statement about the existence of a wind. In ...
... wind signatures. SMP LMC 62 has questionable O vi wind features, and its UV lines are contaminated by nebular emission features. The FUSE spectrum of SMP LMC 35, the dimmest object, has the lowest S/ N and is not of sufficient quality to make a definitive statement about the existence of a wind. In ...
Properties of simulated Milky Way-mass galaxies in loose group and
... pairs (Ellison et al. 2008; Michel-Dansac et al. 2008; Kewley et al. 2010) where the influence on star formation rates extends to projected separations of up to 40 h−1 kpc (Ellison et al. 2008). Interactions are far more common in denser environments and one would expect to see the effect of these in ...
... pairs (Ellison et al. 2008; Michel-Dansac et al. 2008; Kewley et al. 2010) where the influence on star formation rates extends to projected separations of up to 40 h−1 kpc (Ellison et al. 2008). Interactions are far more common in denser environments and one would expect to see the effect of these in ...
Decoding Galaxy Evolution with Gas
... guidance that made this dissertation possible. His excellent grasp of the larger picture continually forced me to understand our results in a broader context. His questions cut straight to the heart of the matter and would evoke sheer terror if asked by anyone who does not possess David’s constantly ...
... guidance that made this dissertation possible. His excellent grasp of the larger picture continually forced me to understand our results in a broader context. His questions cut straight to the heart of the matter and would evoke sheer terror if asked by anyone who does not possess David’s constantly ...
X-ray spectra of highly magnetized neutron stars in binary systems
... whole surface of the neutron star, but from one or two hot spots. This again revealed another striking feature of neutron stars: magnetic fields with a strength B of the order of ∼1012 G. These magnetic fields disrupt the accretion flow and funnel the material along the magnetic field lines to the m ...
... whole surface of the neutron star, but from one or two hot spots. This again revealed another striking feature of neutron stars: magnetic fields with a strength B of the order of ∼1012 G. These magnetic fields disrupt the accretion flow and funnel the material along the magnetic field lines to the m ...
Population effects on the red giant clump absolute magnitude, and
... between the local clump revealed by the Hipparcos colour±magnitude diagram (CMD), and the clump stars observed in distant galaxies. In this paper, we re-address the problem of these systematic `population' effects. First, we present tables with the theoretically predicted I-band clump magnitude as a ...
... between the local clump revealed by the Hipparcos colour±magnitude diagram (CMD), and the clump stars observed in distant galaxies. In this paper, we re-address the problem of these systematic `population' effects. First, we present tables with the theoretically predicted I-band clump magnitude as a ...
Cepheids
... Hertzsprung Sequence of Cepheids (normalized) light curves. Bump position. (from P.Wils) ...
... Hertzsprung Sequence of Cepheids (normalized) light curves. Bump position. (from P.Wils) ...
The Relation between Interstellar Turbulence and Star Formation
... stars have produced the bulk of all chemical el- visible light. It is now possible to observe asements heavier than H and He that made up tronomical objects at wavelengths ranging highthe primordial gas. The Earth itself consists pri- energy γ -rays down to radio frequencies. Espemarily of these hea ...
... stars have produced the bulk of all chemical el- visible light. It is now possible to observe asements heavier than H and He that made up tronomical objects at wavelengths ranging highthe primordial gas. The Earth itself consists pri- energy γ -rays down to radio frequencies. Espemarily of these hea ...
Submm Observations of Massive Star Formation in the Giant
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
Synthetic Light Curves of Shocked Dense Circumstellar Shells
... R-band LC without the bolometric correction. We need to compare LCs in the R band (Figure 1b). We find that the numerical R-band LCs do not match the observed R-band LC even in the models which give a good fit in Figure 1a. This is simply because of high temperatures in the shell and most of the emi ...
... R-band LC without the bolometric correction. We need to compare LCs in the R band (Figure 1b). We find that the numerical R-band LCs do not match the observed R-band LC even in the models which give a good fit in Figure 1a. This is simply because of high temperatures in the shell and most of the emi ...
Present
... Maybe they are more extended starbursts less opacity and less absorption of PAH emission With perhaps strong superwind as in M82 ? But scaled by a factor > 10 enrichment of intergalactic medium in heavy elements?? ...
... Maybe they are more extended starbursts less opacity and less absorption of PAH emission With perhaps strong superwind as in M82 ? But scaled by a factor > 10 enrichment of intergalactic medium in heavy elements?? ...
Three Binary Millisecond Pulsars in NGC 6266
... (minimum masses of 0.12 and 0.07 M, respectively). The pulsar in the closest system is the fifth member of an emerging class of millisecond pulsars displaying irregular radio eclipses and having a relatively massive companion. This system is a good candidate for optical identification of the companio ...
... (minimum masses of 0.12 and 0.07 M, respectively). The pulsar in the closest system is the fifth member of an emerging class of millisecond pulsars displaying irregular radio eclipses and having a relatively massive companion. This system is a good candidate for optical identification of the companio ...
The Evolution of Protostars - Max-Planck
... Herschel results. We focus this review on the progress made with these facilities toward answering several key questions about protostellar evolution, as outlined below. How do surveys find protostars and distinguish them from background galaxies, AGB stars, and more evolved star plus disk systems? ...
... Herschel results. We focus this review on the progress made with these facilities toward answering several key questions about protostellar evolution, as outlined below. How do surveys find protostars and distinguish them from background galaxies, AGB stars, and more evolved star plus disk systems? ...
Star formation in quasar hosts and the origin of radio emission in
... than in type 2s at the same emission line luminosity (Zakamska et al. in preparation). Both these factors suggest that 12 μm luminosity is not an isotropic measure of quasar luminosity and that type 2 quasars are obscured even at mid-infrared wavelengths. The bolometric corrections of type 2 quasars ...
... than in type 2s at the same emission line luminosity (Zakamska et al. in preparation). Both these factors suggest that 12 μm luminosity is not an isotropic measure of quasar luminosity and that type 2 quasars are obscured even at mid-infrared wavelengths. The bolometric corrections of type 2 quasars ...
WTS-1 b: the fi rst extrasolar planet detected in the WFCAM Transit
... Example of the telluric lines in the observed spectra . TELL REMOV: telluric-free spectra . . . . . . . . . . . . CRs filtered spectra with COSMIC REMOV . . . . . . . Correlation function computed with rv.fxcor . . . . All the 64 raw RV values related to each single order Raw RV values related to al ...
... Example of the telluric lines in the observed spectra . TELL REMOV: telluric-free spectra . . . . . . . . . . . . CRs filtered spectra with COSMIC REMOV . . . . . . . Correlation function computed with rv.fxcor . . . . All the 64 raw RV values related to each single order Raw RV values related to al ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.