7 November 2012 X-ray Astrophysics
... so radiate most strongly in the visible waveband. But not all stars are the same temperature or colour: whilst blue stars are at 15,000-80,000 K, yellower stars like our Sun are at 5,000-8000 K and the coolest, reddest stars have temperatures of 2,000-4000K. Of course, many young massive stars are s ...
... so radiate most strongly in the visible waveband. But not all stars are the same temperature or colour: whilst blue stars are at 15,000-80,000 K, yellower stars like our Sun are at 5,000-8000 K and the coolest, reddest stars have temperatures of 2,000-4000K. Of course, many young massive stars are s ...
Potential for Life on the Terrestrial Planets
... have applied a thermal balance model at various XUV flux input values for simulating the thermospheric heating by photodissociation and ionization processes, due to exothermic chemical reactions and cooling by the CO2 IR radiation in the 15 µm band. Our study shows that intense XUV radiation of acti ...
... have applied a thermal balance model at various XUV flux input values for simulating the thermospheric heating by photodissociation and ionization processes, due to exothermic chemical reactions and cooling by the CO2 IR radiation in the 15 µm band. Our study shows that intense XUV radiation of acti ...
Mass transport in the heliosphere by energetic neutral atoms
... in the heliospheric sheath are less subjected to ionization and, consequently, the relative abundances of hydrogen ENAs and interstellar hydrogen could be significantly different in the Sun’s vicinity. Therefore mass transport by heliospheric ENAs may become important. We note that there is another ...
... in the heliospheric sheath are less subjected to ionization and, consequently, the relative abundances of hydrogen ENAs and interstellar hydrogen could be significantly different in the Sun’s vicinity. Therefore mass transport by heliospheric ENAs may become important. We note that there is another ...
Katya Georgieva: Solar dynamo theory – recent progress, questions
... two surges of the toroidal field double-peaked sunspot max ...
... two surges of the toroidal field double-peaked sunspot max ...
(Preprint) AAS 11-665 - Long Now > Media > Uploader
... has not drifted more than 12 hours. This allows the clock to successfully recover after more than a century of overcast skies. In that case it will require at least as many sunny days to recover the correct solar time as the number of 5-minute ticks the clock has drifted, 12 days per hour of drift. ...
... has not drifted more than 12 hours. This allows the clock to successfully recover after more than a century of overcast skies. In that case it will require at least as many sunny days to recover the correct solar time as the number of 5-minute ticks the clock has drifted, 12 days per hour of drift. ...
astro7a_sun_shortv3
... • We can directly measure sound waves moving through the interior • we observe “sunquakes” in the photosphere by using Doppler shifts • motion of sound waves can be checked against interior conditions predicted by models ...
... • We can directly measure sound waves moving through the interior • we observe “sunquakes” in the photosphere by using Doppler shifts • motion of sound waves can be checked against interior conditions predicted by models ...
The Electric Universe by Wallace Thornhill and David Talbott
... models, physicists imagined vast regions of invisible ‘dark matter.’ Since no one could see it, they were free to place it wherever needed to preserve appearances. Then, when other dubious assumptions led them to think that the universe is expanding ever faster—the ultimate violation of gravitationa ...
... models, physicists imagined vast regions of invisible ‘dark matter.’ Since no one could see it, they were free to place it wherever needed to preserve appearances. Then, when other dubious assumptions led them to think that the universe is expanding ever faster—the ultimate violation of gravitationa ...
On the dimensionally correct kinetic theory of turbulence
... the underlying equations can be readily solved by computational means. This cannot be accomplished unless the foundational nonlinear response functions—which are expressed in terms of formal momentum integrals over the derivatives of the particle distribution functions, and also involve multiple inf ...
... the underlying equations can be readily solved by computational means. This cannot be accomplished unless the foundational nonlinear response functions—which are expressed in terms of formal momentum integrals over the derivatives of the particle distribution functions, and also involve multiple inf ...
Can a Fast-Mode EUV Wave Generate a Stationary Front?
... it becomes very similar to the piston-driven shock wave straddling over the source active region as numerically simulated by Chen et al. (2002). The two flanks of the shock wave sweep the flux systems in the background and the separatrices between neighboring flux systems. As revealed by Figure 3, t ...
... it becomes very similar to the piston-driven shock wave straddling over the source active region as numerically simulated by Chen et al. (2002). The two flanks of the shock wave sweep the flux systems in the background and the separatrices between neighboring flux systems. As revealed by Figure 3, t ...
ABSTRACT XMM-Newton X-Ray Spectroscopy of the B2 Bright Giant
... For several decades there have been two major theories of X-ray production on 0 and B stars: coronal heating, and radiatively driven wind shocks (Cohen et al. 1996). The first theory is that the X-rays are produced in the corona, near the surface of the star. Coronal heating requires the presence of ...
... For several decades there have been two major theories of X-ray production on 0 and B stars: coronal heating, and radiatively driven wind shocks (Cohen et al. 1996). The first theory is that the X-rays are produced in the corona, near the surface of the star. Coronal heating requires the presence of ...
pdf - at www.arxiv.org.
... important by itself. These properties must also be discussed with other general properties of GM events, such as their possible cyclicity or stochastic nature, which are under debate. Although giant planets quasi-conjunctions are events that generate very particular gravitational forces, so far, no ...
... important by itself. These properties must also be discussed with other general properties of GM events, such as their possible cyclicity or stochastic nature, which are under debate. Although giant planets quasi-conjunctions are events that generate very particular gravitational forces, so far, no ...
The imprint of the crustal magnetic field on the thermal
... tran codes by A. Potekhin (Potekhin 1999; Potekhin et al. 1999; Cassisi et al. 2007; Chugunov & Haensel 2007), which are available online1 . At fixed temperature, transport across magnetic field lines is strongly suppressed for high magnetic field strengths, because ωB ∝ B, and the anisotropy in the ...
... tran codes by A. Potekhin (Potekhin 1999; Potekhin et al. 1999; Cassisi et al. 2007; Chugunov & Haensel 2007), which are available online1 . At fixed temperature, transport across magnetic field lines is strongly suppressed for high magnetic field strengths, because ωB ∝ B, and the anisotropy in the ...
seismic constraints on interior solar convection
... are able to bound from above the magnitudes of solar convective cells as a function of spatial convective scale. We find that convection at a depth of r/R = 0.95 with spatial extent < 20, where is the spherical harmonic degree, comprises weak flow systems, on the order of 15 m s−1 or less. Conv ...
... are able to bound from above the magnitudes of solar convective cells as a function of spatial convective scale. We find that convection at a depth of r/R = 0.95 with spatial extent < 20, where is the spherical harmonic degree, comprises weak flow systems, on the order of 15 m s−1 or less. Conv ...
Infrared Solar Physics - National Optical Astronomy Observatory
... “Why does anyone still observe the Sun using visible wavelengths of light?” a colleague recently asked of me. Certainly night-time astronomers have been exploiting the infrared spectrum for many years to address critical science questions in that field. The spatial resolution, flux and background pr ...
... “Why does anyone still observe the Sun using visible wavelengths of light?” a colleague recently asked of me. Certainly night-time astronomers have been exploiting the infrared spectrum for many years to address critical science questions in that field. The spatial resolution, flux and background pr ...
Electromagnetic field intensity distribution along focal region of a
... fields is important in the current arena of advanced technologies for microwave, millimeter-wave, and optical device applications. The analysis of focal region filed is useful for optical spectroscopy, medical treatment and hyperthermia. The image field may be also useful to generate images of the h ...
... fields is important in the current arena of advanced technologies for microwave, millimeter-wave, and optical device applications. The analysis of focal region filed is useful for optical spectroscopy, medical treatment and hyperthermia. The image field may be also useful to generate images of the h ...
Particle kinematics in solar flares: observations - ETH E
... Solar flares are amongst the most powerful and energetic activity phenomena our Sun exhibits. They release energy of the order of 1032 erg in seconds to minutes. In the process, electrons and protons are accelerated to relativistic energies, making flares very efficient particle accelerators. The mo ...
... Solar flares are amongst the most powerful and energetic activity phenomena our Sun exhibits. They release energy of the order of 1032 erg in seconds to minutes. In the process, electrons and protons are accelerated to relativistic energies, making flares very efficient particle accelerators. The mo ...
Excitation of transverse magnetic tube waves in stellar convection
... external turbulent motions. The tube is embedded in a non-magnetic medium and is assumed to be thin and oriented vertically. Its interaction with the external turbulence, which is considered to be subsonic and known a priori, is assumed to be weak enough so that only linear transverse tube waves are ...
... external turbulent motions. The tube is embedded in a non-magnetic medium and is assumed to be thin and oriented vertically. Its interaction with the external turbulence, which is considered to be subsonic and known a priori, is assumed to be weak enough so that only linear transverse tube waves are ...
Sun Powerpoint
... http://www.answersingenesis.org/assets/images/articles/tba/chapter-one/sun-moon-earth.jpg http://www.astro.washington.edu/labs/clearinghouse/labs/Propsun/images/chang_sun2.gif http://hometown.aol.com/falconmaster29/downloads/SolarFlare.jpg http://www.nasa.gov/images/content/171925main_heliolayers_la ...
... http://www.answersingenesis.org/assets/images/articles/tba/chapter-one/sun-moon-earth.jpg http://www.astro.washington.edu/labs/clearinghouse/labs/Propsun/images/chang_sun2.gif http://hometown.aol.com/falconmaster29/downloads/SolarFlare.jpg http://www.nasa.gov/images/content/171925main_heliolayers_la ...
Galaxy / Cluster Ecosystem Ming Sun (University of Alabama in Huntsville)
... Coronae survived for many cluster galaxies, esp. massive ones (e.g., > 60 % for L > 2 L* galaxies); they are metal rich ( ~ solar) and hotter than stars (spec = 0.3 – 1.1). Origin: a) galactic cool cores (stellar mass loss); b) remnants of large cool cores after stripping or AGN heating? Embedded c ...
... Coronae survived for many cluster galaxies, esp. massive ones (e.g., > 60 % for L > 2 L* galaxies); they are metal rich ( ~ solar) and hotter than stars (spec = 0.3 – 1.1). Origin: a) galactic cool cores (stellar mass loss); b) remnants of large cool cores after stripping or AGN heating? Embedded c ...
ASTROPHYSICS LAB: THE LUMINOSITY OF THE SUN
... c) reasons for the calculated answer being too low or too high or have no effect (1) the orbit of the earth around the sun is not perfectly circular; on or around January 3, the earth is closest to the sun (1.7% closer than average)... on or around July 4, the earth is farthest from the sun (1.7% fa ...
... c) reasons for the calculated answer being too low or too high or have no effect (1) the orbit of the earth around the sun is not perfectly circular; on or around January 3, the earth is closest to the sun (1.7% closer than average)... on or around July 4, the earth is farthest from the sun (1.7% fa ...
Theory of pulsar winds and nebulae - Max-Planck
... If one traces the escaping (“open”) magnetic field lines back to the stellar surface, they define areas which, in a dipole geometry, lie close to the magnetic axis and are called “polar caps”. To maintain a steady state, plasma must be continuously generated on the open field lines in these polar re ...
... If one traces the escaping (“open”) magnetic field lines back to the stellar surface, they define areas which, in a dipole geometry, lie close to the magnetic axis and are called “polar caps”. To maintain a steady state, plasma must be continuously generated on the open field lines in these polar re ...
Particle acceleration and synchrotron emission in blazar jets
... so weak, that no significant further contribution to the emitted spectrum arises, despite the fact that particles accumulate there over the entire life of the source. However, a problem arises in the homogeneous model concerning time variability – only if the physical dimensions of the source are su ...
... so weak, that no significant further contribution to the emitted spectrum arises, despite the fact that particles accumulate there over the entire life of the source. However, a problem arises in the homogeneous model concerning time variability – only if the physical dimensions of the source are su ...
Development of electric currents in a magnetic field configuration
... field. The currents should satisfy ∇ · J = 0, hence, perpendicular currents might connect to return currents to close the current system. The currents propagate along the field lines at the local Alfvén speed, following the perturbations of the magnetic field. It is known that fast-mode waves can al ...
... field. The currents should satisfy ∇ · J = 0, hence, perpendicular currents might connect to return currents to close the current system. The currents propagate along the field lines at the local Alfvén speed, following the perturbations of the magnetic field. It is known that fast-mode waves can al ...
The role of the sun in climate forcing
... The long-term energy #ow from the sun (luminositiy) is determined by the fusion rate of hydrogen to helium in the solar core on a billion year time scale and follows a hyperbolic trend (Fig. 1) (Gough, 1977). The deviations from this trend are extremely small. From physical models of the Sun's evolu ...
... The long-term energy #ow from the sun (luminositiy) is determined by the fusion rate of hydrogen to helium in the solar core on a billion year time scale and follows a hyperbolic trend (Fig. 1) (Gough, 1977). The deviations from this trend are extremely small. From physical models of the Sun's evolu ...
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.