ph507weeks1
... Technological advances (including the Hubble Space Telescope) have improved parallax accuracy to 0.001” within a few years. Before 1990, fewer than 10,000 stellar parallaxes had been measured (and only 500 known well), but there are about 1012 stars in our Galaxy. Space observations made by the Euro ...
... Technological advances (including the Hubble Space Telescope) have improved parallax accuracy to 0.001” within a few years. Before 1990, fewer than 10,000 stellar parallaxes had been measured (and only 500 known well), but there are about 1012 stars in our Galaxy. Space observations made by the Euro ...
On gamma-ray emission from pulsar magnetosphere
... understood within a model of a unipolar inductor generating very large v x B electric fields capable of pulling charges from the neutron star surface against the force of gravity. Hence, the magnetosphere of the neutron star is filled with charge separated plasma that tends to oppose the induced v x ...
... understood within a model of a unipolar inductor generating very large v x B electric fields capable of pulling charges from the neutron star surface against the force of gravity. Hence, the magnetosphere of the neutron star is filled with charge separated plasma that tends to oppose the induced v x ...
The first focused hard X-ray images of the sun with
... asymptotes toward a maximum of 400 counts s−1 per telescope as the incident count rate increases. In practice this can mean that fainter secondary spectral components (e.g., hot plasma from above an active region or non-thermal emissions from accelerated electrons) may produce small numbers of obser ...
... asymptotes toward a maximum of 400 counts s−1 per telescope as the incident count rate increases. In practice this can mean that fainter secondary spectral components (e.g., hot plasma from above an active region or non-thermal emissions from accelerated electrons) may produce small numbers of obser ...
McConnell XGPolarimetry SSE
... Controversy remains over the site of this emission - directly above the polar cap, where the coherent radio pulses originate [e.g., 1], in the the outer magnetosphere near the light cylinder radius [e.g., 2], or in the so called "slot gap'' along the open magnetic field lines between the polar cap a ...
... Controversy remains over the site of this emission - directly above the polar cap, where the coherent radio pulses originate [e.g., 1], in the the outer magnetosphere near the light cylinder radius [e.g., 2], or in the so called "slot gap'' along the open magnetic field lines between the polar cap a ...
T. Thompson, Jan 2007
... – Because from secondary electrons/positrons, another process (not synchrotron) must dominate CR electron cooling. ...
... – Because from secondary electrons/positrons, another process (not synchrotron) must dominate CR electron cooling. ...
Differential rotation of the Sun
... latitudes have different angular velocities. The most obvious being tracking spots on the stellar surface. By doing helioseismological measurements of solar "p-modes" it is possible to deduce the differential rotation. The Sun has very many acoustic modes that oscillate in the interior simultaneousl ...
... latitudes have different angular velocities. The most obvious being tracking spots on the stellar surface. By doing helioseismological measurements of solar "p-modes" it is possible to deduce the differential rotation. The Sun has very many acoustic modes that oscillate in the interior simultaneousl ...
Star-Planet Interactions
... and differences with the Sun-planet interactions. In the Solar system, planets are located√in a region where the velocity of the solar wind vw is greater than the local Alfven velocity vA = B/ µρ, where B is the magnetic field in the interplanetary space, µ the permeability of the plasma, and ρ its ...
... and differences with the Sun-planet interactions. In the Solar system, planets are located√in a region where the velocity of the solar wind vw is greater than the local Alfven velocity vA = B/ µρ, where B is the magnetic field in the interplanetary space, µ the permeability of the plasma, and ρ its ...
PHY418 Particle Astrophysics
... • But it’s quite hard to work out how they do it • magnetic geometry at the termination shock must be quasiperpendicular, which disfavours diffusive shock acceleration • but maybe enough small-scale turbulence is generated at the shock • the expected electron power law of E−2.2 is right for the Crab ...
... • But it’s quite hard to work out how they do it • magnetic geometry at the termination shock must be quasiperpendicular, which disfavours diffusive shock acceleration • but maybe enough small-scale turbulence is generated at the shock • the expected electron power law of E−2.2 is right for the Crab ...
Solaria Binaria - The Grazian Archive
... stellar binaries elsewhere. The explosive or catastrophic Universe poses basic problems to chronology. The span of astronomical time has been increasing dramatically even in the face of time-collapsing explosive events that reduce drastically the constraints upon time as a factor in change. Great st ...
... stellar binaries elsewhere. The explosive or catastrophic Universe poses basic problems to chronology. The span of astronomical time has been increasing dramatically even in the face of time-collapsing explosive events that reduce drastically the constraints upon time as a factor in change. Great st ...
Chandra HETGS Multiphase Spectroscopy Of The Young
... the field still manages to divert some material toward the magnetic equator, leading to a noticeable density enhancement. Because the magnetic field energy density falls off significantly faster than the wind kinetic energy density, at large radii the wind always dominates over the field, even for ...
... the field still manages to divert some material toward the magnetic equator, leading to a noticeable density enhancement. Because the magnetic field energy density falls off significantly faster than the wind kinetic energy density, at large radii the wind always dominates over the field, even for ...
GCR Neon Isotopic Abundances: Comparison with Wolf
... stars in the high velocity winds have incorporated the lower WR mass loss rates, updated nuclear reaction rates, and extended the reaction networks included in the models. Additionally, they have considered the effects of rotation, which has a strong effect on isotopic production. Their model is a t ...
... stars in the high velocity winds have incorporated the lower WR mass loss rates, updated nuclear reaction rates, and extended the reaction networks included in the models. Additionally, they have considered the effects of rotation, which has a strong effect on isotopic production. Their model is a t ...
Jack Eddy`s Study of the Maunder Minimum Inspires a Long Series
... Spectral Regions of the Solar Spectrum ...
... Spectral Regions of the Solar Spectrum ...
EQUATION OF STATE AND OPACITIES FOR HYDROGEN
... We present an equation of state and radiative opacities for a strongly magnetized hydrogen plasma at magnetic fields B, temperatures T, and densities typical for atmospheres of isolated neutron stars. The first- and second-order thermodynamic functions, monochromatic radiative opacities, and Rosse ...
... We present an equation of state and radiative opacities for a strongly magnetized hydrogen plasma at magnetic fields B, temperatures T, and densities typical for atmospheres of isolated neutron stars. The first- and second-order thermodynamic functions, monochromatic radiative opacities, and Rosse ...
UVIS Team Meeting - Laboratory for Atmospheric and Space Physics
... Review of FUV results explains modeling technique solar angles are average over disk the UVIS disk airglow spectrum and regression model fit over the spectral range of 1150-1750 Å is shown in Figure. It is observed that there are about 20 well-defined emission features from the LBH bands of N2 and t ...
... Review of FUV results explains modeling technique solar angles are average over disk the UVIS disk airglow spectrum and regression model fit over the spectral range of 1150-1750 Å is shown in Figure. It is observed that there are about 20 well-defined emission features from the LBH bands of N2 and t ...
PDF - Isaac Scientific Publishing
... corresponds directly to the observed time given in the ancient sources, while ET needs to be calibrated. The great problem with this calibration is that it is impossible to avoid circular arguments for the ancient observations, and the period of telescopic observations used by Morrison and Ward in c ...
... corresponds directly to the observed time given in the ancient sources, while ET needs to be calibrated. The great problem with this calibration is that it is impossible to avoid circular arguments for the ancient observations, and the period of telescopic observations used by Morrison and Ward in c ...
Cross-sectional area and intensity variations of sausage modes⋆
... expected φδφB,0B = 0. Note that the terms in Eqs. (12)–(14) before J1 (nR)/nR are the same as the terms in Eqs. (9)–(11) before I1 (κR)/κR. We shall use I1 to indicate the first term in Eq. (9), I2 to indicate the second term in Eq. (9), and S 1 to indicate the first term in Eq. (10). Looking at Eqs ...
... expected φδφB,0B = 0. Note that the terms in Eqs. (12)–(14) before J1 (nR)/nR are the same as the terms in Eqs. (9)–(11) before I1 (κR)/κR. We shall use I1 to indicate the first term in Eq. (9), I2 to indicate the second term in Eq. (9), and S 1 to indicate the first term in Eq. (10). Looking at Eqs ...
3D WHOLE-PROMINENCE FINE STRUCTURE MODELING
... of the gravity-induced dips of Heinzel & Anzer (2001). These authors developed a novel iterative technique to fill magnetic dips with prominence plasma in hydrostatic equilibrium. They used a semi-empirical temperature structure that includes the PCTR, similar to that used by Heinzel & Anzer (2001). ...
... of the gravity-induced dips of Heinzel & Anzer (2001). These authors developed a novel iterative technique to fill magnetic dips with prominence plasma in hydrostatic equilibrium. They used a semi-empirical temperature structure that includes the PCTR, similar to that used by Heinzel & Anzer (2001). ...
Slide 1
... match the current luminosity and radius of the Sun One input to models is ratio of mass fraction of H ( = X) to mass fraction of heavy elements (= Z) Mass fraction of He ( = Y) follows from X + Y + Z = 1 Z is the sum of the mass fraction of all elements heavier than He (the “metals”) Z is dominated ...
... match the current luminosity and radius of the Sun One input to models is ratio of mass fraction of H ( = X) to mass fraction of heavy elements (= Z) Mass fraction of He ( = Y) follows from X + Y + Z = 1 Z is the sum of the mass fraction of all elements heavier than He (the “metals”) Z is dominated ...
The Cosmic Rays and Our Galaxy
... presented in Sect. 2.6. Most CRs originate outside the solar system and the physical properties of the Galaxy (dimension, matter density, magnetic fields, described in Sect. 2.7) have an effect on their journey from sources to the Earth. Only low-energy particles (below few GeV) are of solar origin ...
... presented in Sect. 2.6. Most CRs originate outside the solar system and the physical properties of the Galaxy (dimension, matter density, magnetic fields, described in Sect. 2.7) have an effect on their journey from sources to the Earth. Only low-energy particles (below few GeV) are of solar origin ...
Flare Observations
... at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ra ...
... at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ra ...
Large-scale magnetic flux concentrations from turbulent stresses 331 A. Brandenburg , N. Kleeorin
... 1 Introduction Turbulence effects generally refer to the occurrence of correlations between components of velocity, temperature, and/or magnetic fields at small scales. A typical example is turbulent viscosity, which results from the spatial exchange of turbulent eddies characterized by velocity cor ...
... 1 Introduction Turbulence effects generally refer to the occurrence of correlations between components of velocity, temperature, and/or magnetic fields at small scales. A typical example is turbulent viscosity, which results from the spatial exchange of turbulent eddies characterized by velocity cor ...
Altair -- the ``hottest`` magnetically active star in X-rays
... periods of Altair are close to each other, supporting that rotational modulated X-ray emission is indeed present during the observation. The absence of larger or even moderate flares, which are commonly observed in more active stars, may be a chance effect, but indicates the rareness of such events ...
... periods of Altair are close to each other, supporting that rotational modulated X-ray emission is indeed present during the observation. The absence of larger or even moderate flares, which are commonly observed in more active stars, may be a chance effect, but indicates the rareness of such events ...
New Suns in the Cosmos?
... IDs 100746852, 102709980, and 105693572, present periods in the range ≈ 25 ± 5 days, i.e., matching closely the Sun’s rotation period, which is 24.47 days at the equator, 33.5 days on the poles, and 26.09 days on average (Lanza et al. 2003; Mamajek 2012). Physical parameters of the selected candidat ...
... IDs 100746852, 102709980, and 105693572, present periods in the range ≈ 25 ± 5 days, i.e., matching closely the Sun’s rotation period, which is 24.47 days at the equator, 33.5 days on the poles, and 26.09 days on average (Lanza et al. 2003; Mamajek 2012). Physical parameters of the selected candidat ...
Numerical models of sunspot formation and fine structure
... Sunspots are central to our understanding of solar (and stellar) magnetism in many respects. On the large scale, they link the magnetic field observable in the photosphere to the dynamo processes operating in the solar interior. Properly interpreting the constraints that sunspots impose on the dynamo ...
... Sunspots are central to our understanding of solar (and stellar) magnetism in many respects. On the large scale, they link the magnetic field observable in the photosphere to the dynamo processes operating in the solar interior. Properly interpreting the constraints that sunspots impose on the dynamo ...
Solar Irradiance
... future impacts that these changes can have on the global community, it is important to understand the factors which cause climate change to take place. One important aspect, which has been linked to climate change by scientists and used by climate change skeptics as an argument against human-induced ...
... future impacts that these changes can have on the global community, it is important to understand the factors which cause climate change to take place. One important aspect, which has been linked to climate change by scientists and used by climate change skeptics as an argument against human-induced ...
Corona
A corona (Latin, 'crown') is an aura of plasma that surrounds the sun and other celestial bodies. The Sun's corona extends millions of kilometres into space and is most easily seen during a total solar eclipse, but it is also observable with a coronagraph. The word ""corona"" is a Latin word meaning ""crown"", from the Ancient Greek κορώνη (korōnē, “garland, wreath”).The high temperature of the Sun's corona gives it unusual spectral features, which led some in the 19th century to suggest that it contained a previously unknown element, ""coronium"". Instead, these spectral features have since been explained by highly ionized iron (Fe-XIV). Bengt Edlén, following the work of Grotrian (1939), first identified the coronal lines in 1940 (observed since 1869) as transitions from low-lying metastable levels of the ground configuration of highly ionised metals (the green Fe-XIV line at 5303 Å, but also the red line Fe-X at 6374 Å). These high stages of ionisation indicate a plasma temperature in excess of 1,000,000 kelvin, much hotter than the surface of the sun.Light from the corona comes from three primary sources, which are called by different names although all of them share the same volume of space. The K-corona (K for kontinuierlich, ""continuous"" in German) is created by sunlight scattering off free electrons; Doppler broadening of the reflected photospheric absorption lines completely obscures them, giving the spectral appearance of a continuum with no absorption lines. The F-corona (F for Fraunhofer) is created by sunlight bouncing off dust particles, and is observable because its light contains the Fraunhofer absorption lines that are seen in raw sunlight; the F-corona extends to very high elongation angles from the Sun, where it is called the zodiacal light. The E-corona (E for emission) is due to spectral emission lines produced by ions that are present in the coronal plasma; it may be observed in broad or forbidden or hot spectral emission lines and is the main source of information about the corona's composition.