The effects of galaxy interactions on star formation
... the star cluster populations of the interacting galaxies Arp 284 (NGC 7714/5) and Arp 261, using data from the Hubble Space Telescope along with ancillary data from the Spitzer Space Telescope and Galaxy Evolution Explorer to obtain broader wavelength coverage. Combined with starburst99 evolutionary ...
... the star cluster populations of the interacting galaxies Arp 284 (NGC 7714/5) and Arp 261, using data from the Hubble Space Telescope along with ancillary data from the Spitzer Space Telescope and Galaxy Evolution Explorer to obtain broader wavelength coverage. Combined with starburst99 evolutionary ...
High-mass X-ray Binaries: X-raying the winds Ángel Giménez García
... XSPEC, versión 12.8.08 , especializado en el ajuste de modelos a espectros de rayos X. En la Tabla 4.2 presentamos todos los modelos del continuo que hemos probado en cada uno de los espectros analizados. Los modelos has sido aceptados o rechazados en función del χ2 -reducido asociado a cada ajuste ...
... XSPEC, versión 12.8.08 , especializado en el ajuste de modelos a espectros de rayos X. En la Tabla 4.2 presentamos todos los modelos del continuo que hemos probado en cada uno de los espectros analizados. Los modelos has sido aceptados o rechazados en función del χ2 -reducido asociado a cada ajuste ...
Photometric Variability and Rotation in Magnetic White Dwarfs
... emerged between the spin period and magnetic field strength and temperature, suggesting hotter MWDs spin faster and have higher field strengths, characteristics possibly associated with MWDs that might have formed in binary mergers. A similar investigation is carried out on longer timescales (months ...
... emerged between the spin period and magnetic field strength and temperature, suggesting hotter MWDs spin faster and have higher field strengths, characteristics possibly associated with MWDs that might have formed in binary mergers. A similar investigation is carried out on longer timescales (months ...
Physics of Neutron Star Crusts
... is expected to be very different from that formed during the aftermath of a supernova explosion. We show how it can be a site for nuclear reactions. We study its thermal structure during accretion, and briefly review the phenomenon of X-ray bursts. We quantitatively analyze the phenomenon of deep cru ...
... is expected to be very different from that formed during the aftermath of a supernova explosion. We show how it can be a site for nuclear reactions. We study its thermal structure during accretion, and briefly review the phenomenon of X-ray bursts. We quantitatively analyze the phenomenon of deep cru ...
On the Rising of the Pleiades
... On November 18, the Pleiades are in opposition—1800 from the sun, rising at sunset, culminating at midnight, and setting at sunrise (fig. 6). It is of interest—perhaps significance—that culmination in Hawai'i occurs at the zenith. But the Pleiades rising at opposition is a non-event; it cannot be se ...
... On November 18, the Pleiades are in opposition—1800 from the sun, rising at sunset, culminating at midnight, and setting at sunrise (fig. 6). It is of interest—perhaps significance—that culmination in Hawai'i occurs at the zenith. But the Pleiades rising at opposition is a non-event; it cannot be se ...
Physics of Neutron Star Crusts - Institut d`Astronomie et d
... (Section 3.1) is formed of a body centered cubic lattice of iron 56 Fe. At ρ ∼ 104 g/cm3 , the atoms are fully ionized owing to the high density. At densities above 107 g/cm3 , the composition of the nuclei becomes more neutron rich as a result of electron captures. The inner crust (Section 3.2), wh ...
... (Section 3.1) is formed of a body centered cubic lattice of iron 56 Fe. At ρ ∼ 104 g/cm3 , the atoms are fully ionized owing to the high density. At densities above 107 g/cm3 , the composition of the nuclei becomes more neutron rich as a result of electron captures. The inner crust (Section 3.2), wh ...
Accretion Power in Astrophysics, Third Editiion
... the larger the ratio M/R∗ , the greater the efficiency. Thus, in treating accretion on to objects of stellar mass we shall certainly want to consider neutron stars (R∗ ∼ 10 km) and black holes with radii R∗ ∼ 2GM/c2 ∼ 3(M/M ) km (see Section 7.7). For white dwarfs with M ∼ M , R∗ ∼ 109 cm, nuclear b ...
... the larger the ratio M/R∗ , the greater the efficiency. Thus, in treating accretion on to objects of stellar mass we shall certainly want to consider neutron stars (R∗ ∼ 10 km) and black holes with radii R∗ ∼ 2GM/c2 ∼ 3(M/M ) km (see Section 7.7). For white dwarfs with M ∼ M , R∗ ∼ 109 cm, nuclear b ...
Contents - arXiv.org
... Gravitational Microlensing can be thought of as a version of strong gravitational lensing in which the image separation is too small to be resolved. Multiple images are formed, but their typical separation – ∆θ ≈ 2 θE – is far below the limiting resolution determined by observational constraints. Gi ...
... Gravitational Microlensing can be thought of as a version of strong gravitational lensing in which the image separation is too small to be resolved. Multiple images are formed, but their typical separation – ∆θ ≈ 2 θE – is far below the limiting resolution determined by observational constraints. Gi ...
MASSIVE GALAXIES IN COSMOLOGICAL SIMULATIONS: ULTRAVIOLET-SELECTED
... stellar masses of k1011 M, and their observed-frame GR colors lie in the range 0:0 < G R < 1:0. They typically have been continuously forming stars at a rate exceeding 30 M yr1 over a few gigayears from z ¼ 10 to z ¼ 2, although the TVD simulation indicates a more sporadic star formation histo ...
... stellar masses of k1011 M, and their observed-frame GR colors lie in the range 0:0 < G R < 1:0. They typically have been continuously forming stars at a rate exceeding 30 M yr1 over a few gigayears from z ¼ 10 to z ¼ 2, although the TVD simulation indicates a more sporadic star formation histo ...
Co-production of Nitrogen-15 and Oxygen-18 in
... 4 times the solar value in the green perimeter while the δ 18 O/16 O value peaks at 5200 parts per mil in the two red spots, corresponding to ...
... 4 times the solar value in the green perimeter while the δ 18 O/16 O value peaks at 5200 parts per mil in the two red spots, corresponding to ...
Kuchnig_CW8 - Sciences et techniques
... • eta Boo - follow up for consistency check • tau Boo - follow up on orbital/rotation signatures seen in 2004 • eps Oph - red Giant p-mode investigation (just started…) ...
... • eta Boo - follow up for consistency check • tau Boo - follow up on orbital/rotation signatures seen in 2004 • eps Oph - red Giant p-mode investigation (just started…) ...
The COMPLETE Survey of Outflows in Perseus
... the shocked gas. This is why CO has mostly been used for studying the impact of outflows on the surrounding molecular cloud. However, the CO fails as an outflow tracer in regions where there is little molecular gas (i.e., in the outskirts of the cloud), and so molecular outflows give a lower limit o ...
... the shocked gas. This is why CO has mostly been used for studying the impact of outflows on the surrounding molecular cloud. However, the CO fails as an outflow tracer in regions where there is little molecular gas (i.e., in the outskirts of the cloud), and so molecular outflows give a lower limit o ...
Full Text - University of Toronto Astronomy
... In this dissertation, we develop new tools for the study of stellar atmospheres, pulsating stellar atmospheres and mass loss from pulsating stars. These tools provide new insights into the structure and evolution of stars and complement modern observational techniques such as optical interferometry ...
... In this dissertation, we develop new tools for the study of stellar atmospheres, pulsating stellar atmospheres and mass loss from pulsating stars. These tools provide new insights into the structure and evolution of stars and complement modern observational techniques such as optical interferometry ...
Direct Evidence for Termination of Obscured Star Formation by
... presence of both starburst and AGN activity in many IR-luminous systems at all redshifts (see e.g. Blain et al. 2002; Lagache et al. 2005; Lonsdale et al. 2006; Hernán-Caballero et al. 2009). Recently, interest into the relationship between starburst and AGN activity has been stimulated by what fir ...
... presence of both starburst and AGN activity in many IR-luminous systems at all redshifts (see e.g. Blain et al. 2002; Lagache et al. 2005; Lonsdale et al. 2006; Hernán-Caballero et al. 2009). Recently, interest into the relationship between starburst and AGN activity has been stimulated by what fir ...
PPT - IAC
... R Aqr nebula known since 1921 (Lampland 1923 PAAS 4, 319), but the concept that a large fraction of symbiotic Miras have (collimated) nebulae very similar to PNe, which illustrate the potential importance of binary interactions for the shaping of PNe, started growing from the moment that Hugo discov ...
... R Aqr nebula known since 1921 (Lampland 1923 PAAS 4, 319), but the concept that a large fraction of symbiotic Miras have (collimated) nebulae very similar to PNe, which illustrate the potential importance of binary interactions for the shaping of PNe, started growing from the moment that Hugo discov ...
VLA OBSERVATIONS OF AMMONIA IN HIGH
... and to resolve the energy feedback (Liu et al. 2012a; Wang et al. 2012). An example is a recent study by Sánchez-Monge et al. (2013) that reported 0.05 pc resolution National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) NH3 observations towards 15 intermediate-/high-mass star-forming r ...
... and to resolve the energy feedback (Liu et al. 2012a; Wang et al. 2012). An example is a recent study by Sánchez-Monge et al. (2013) that reported 0.05 pc resolution National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) NH3 observations towards 15 intermediate-/high-mass star-forming r ...
The Prevalence and Compositions of Small Planets The Harvard
... intelligent life beyond the Earth. The answer to that question is still unknown, but the prospects for detecting life elsewhere in the universe have changed considerably over the last twenty years. Prior to the first detections of planets orbiting other stars, astronomers could only speculate whethe ...
... intelligent life beyond the Earth. The answer to that question is still unknown, but the prospects for detecting life elsewhere in the universe have changed considerably over the last twenty years. Prior to the first detections of planets orbiting other stars, astronomers could only speculate whethe ...
Jets and Outflows From Star to Cloud: Observations Confront Theory
... also affect disk evolution and planet formation through disk irradiation or shielding, and enhanced radial mixing of both gas and solids. In this chapter we address this central question of outflow feedback on star and planet formation while also reviewing the current state of jet/outflow science. F ...
... also affect disk evolution and planet formation through disk irradiation or shielding, and enhanced radial mixing of both gas and solids. In this chapter we address this central question of outflow feedback on star and planet formation while also reviewing the current state of jet/outflow science. F ...
Observed emission rates in sprite streamer heads
... [8] The streamer heads are slightly elongated in the direction of propagation. With 50 ms gating the streamer heads would move 2 – 3 pixels during the exposure time. Thus the elongation appears to be an artifact of velocity. The streamer heads are brightest in the center and a Gaussian profile fits ...
... [8] The streamer heads are slightly elongated in the direction of propagation. With 50 ms gating the streamer heads would move 2 – 3 pixels during the exposure time. Thus the elongation appears to be an artifact of velocity. The streamer heads are brightest in the center and a Gaussian profile fits ...
Post-Common-Envelope Binaries from the Sloan Digital Sky Survey
... I deeply thank Dr. Boris Gänsicke for his excellent guidance through my PhD, for his help and suggestions, and most importantly for making it possible for me to develop my qualities as a researcher. I am also deeply thankful for his trust in me in this and other projects. Without him this thesis wo ...
... I deeply thank Dr. Boris Gänsicke for his excellent guidance through my PhD, for his help and suggestions, and most importantly for making it possible for me to develop my qualities as a researcher. I am also deeply thankful for his trust in me in this and other projects. Without him this thesis wo ...
Spherical planetary nebulae
... large spherical halo but an inner elliptical region is classified as an elliptical, rather than round PN. (3) Due to large uncertainties in the distances to PNe, and the fact that the PNe images are from very different telescopes and researchers, it will be difficult to use any meaningful subsample. ...
... large spherical halo but an inner elliptical region is classified as an elliptical, rather than round PN. (3) Due to large uncertainties in the distances to PNe, and the fact that the PNe images are from very different telescopes and researchers, it will be difficult to use any meaningful subsample. ...
Magnetic fields and mass loss in massive stars
... On the main sequence, magnetic fields are frequently found in late-type stars, which are thought to have dynamo generated fields, and in the chemically peculiar Ap/Bp stars. The chemical peculiarities in these stars are related to their strong magnetic fields. Only recently magnetic fields have been ...
... On the main sequence, magnetic fields are frequently found in late-type stars, which are thought to have dynamo generated fields, and in the chemically peculiar Ap/Bp stars. The chemical peculiarities in these stars are related to their strong magnetic fields. Only recently magnetic fields have been ...
Full Text - Digital Access to Scholarship at Harvard
... has a broad range of energy levels and can interact with light over much of a star’s spectrum, whereas atomic hydrogen gas, for instance, can interact with light primarily only within a few lines for all wavelengths longward of ionizing hydrogen. Because of this, about 30% of the light leaving the G ...
... has a broad range of energy levels and can interact with light over much of a star’s spectrum, whereas atomic hydrogen gas, for instance, can interact with light primarily only within a few lines for all wavelengths longward of ionizing hydrogen. Because of this, about 30% of the light leaving the G ...
Link - Max-Planck-Institut für Astronomie
... the star formation community. It is now viewed as a common, though still poorly understood, phenomenon in low-mass star formation. The FU Orionis objects (FUors) are long-studied examples of this phenomenon. FUors are believed to undergo accretion outbursts during which the accretion rate rapidly in ...
... the star formation community. It is now viewed as a common, though still poorly understood, phenomenon in low-mass star formation. The FU Orionis objects (FUors) are long-studied examples of this phenomenon. FUors are believed to undergo accretion outbursts during which the accretion rate rapidly in ...
- REAL-J
... IBVS is published on behalf of the 27th and 42nd Commissions of the IAU, by the Konkoly Observatory, Budapest, Hungary. Individual issues could be downloaded for scienti c and educational purposes free of charge. Bibliographic information of the recent issues could be entered to indexing systems. No ...
... IBVS is published on behalf of the 27th and 42nd Commissions of the IAU, by the Konkoly Observatory, Budapest, Hungary. Individual issues could be downloaded for scienti c and educational purposes free of charge. Bibliographic information of the recent issues could be entered to indexing systems. No ...
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.