Time evolution and rotation of starspots on CoRoT
... Sun, Carrington (1863) noticed that their sidereal angular velocity could be approximated by: Ω = A − B cos2 θ, ...
... Sun, Carrington (1863) noticed that their sidereal angular velocity could be approximated by: Ω = A − B cos2 θ, ...
Neutron Stars – Cooling and Transport
... which serves as a mediator of the internal heat into the outgoing thermal radiation. It will be considered in Sect. 5. Solutions to the thermal evolution equations and their implications are briefly reviewed in Sect. 6. For weak magnetic fields, we can assume that the temperature gradients are essen ...
... which serves as a mediator of the internal heat into the outgoing thermal radiation. It will be considered in Sect. 5. Solutions to the thermal evolution equations and their implications are briefly reviewed in Sect. 6. For weak magnetic fields, we can assume that the temperature gradients are essen ...
Injection mechanisms of short-lived radionuclides and their
... timescales. The use of these isotopes as chronometers is, however, predicated on two assumptions: (1) that the SLRs 26Al and 53Mn were distributed homogeneously throughout the Solar System at an early time and (2) the abundances of these isotopes changed only because of radioactive decay, and were n ...
... timescales. The use of these isotopes as chronometers is, however, predicated on two assumptions: (1) that the SLRs 26Al and 53Mn were distributed homogeneously throughout the Solar System at an early time and (2) the abundances of these isotopes changed only because of radioactive decay, and were n ...
Geophysical Turbulence Program
... GTP visitors and graduate students - 07 &/or 08 M-E Brachet, ENS-Paris: codes with symmetries in MHD, RK4 and Euler flow with helicity. J.F. Cossette (grad. student, U. Montreal, with Piotr Smolarkiewicz): Semi-Lagrangian schemes. M. Damron (grad. student, U. Arizona, with Larry Winter): a non-Mark ...
... GTP visitors and graduate students - 07 &/or 08 M-E Brachet, ENS-Paris: codes with symmetries in MHD, RK4 and Euler flow with helicity. J.F. Cossette (grad. student, U. Montreal, with Piotr Smolarkiewicz): Semi-Lagrangian schemes. M. Damron (grad. student, U. Arizona, with Larry Winter): a non-Mark ...
Rotation, activity, and stellar obliquities in a large uniform sample of
... stars which are like the Sun and thus might shed light on characteristics of its composition, structure, activity, planetary system, evolution, and future. Solar analogs are useful in many ways, ranging from finding night-time proxies for the Sun for calibration purposes to their use as snapshots of ...
... stars which are like the Sun and thus might shed light on characteristics of its composition, structure, activity, planetary system, evolution, and future. Solar analogs are useful in many ways, ranging from finding night-time proxies for the Sun for calibration purposes to their use as snapshots of ...
radiation and matter interaction in strong magnetic field of accreting
... It is obvious nowadays that quantum processes are very important to understand the physics of a number of astrophysical objects as well as for the understanding of the processes in the early Universe (Raffelt, 1996). Extreme conditions, including high temperature and density as well as strong electr ...
... It is obvious nowadays that quantum processes are very important to understand the physics of a number of astrophysical objects as well as for the understanding of the processes in the early Universe (Raffelt, 1996). Extreme conditions, including high temperature and density as well as strong electr ...
Latitudinal and radial gradients of galactic cosmic ray protons in the
... and tilt angle (red curve), respectively, indicating a period of several years of very low solar activity. Marked by shading are two periods after the launch of the PAMELA spacecraft in October 2006 and July 2008 when Ulysses was at about 3.5 AU and 50◦ . The polar passes are defined to be those per ...
... and tilt angle (red curve), respectively, indicating a period of several years of very low solar activity. Marked by shading are two periods after the launch of the PAMELA spacecraft in October 2006 and July 2008 when Ulysses was at about 3.5 AU and 50◦ . The polar passes are defined to be those per ...
The Jansky Very Large Array – New Capabilities, New Science
... • Three of the four prior examples employed mm (PdBI) interferometer observations as well as VLA. • The rise of ALMA will strengthen this complementarity, with stellar scientific results. • New example – Wagg and Carilli combine VLA and ALMA for early forming galaxies: – Massive galaxies at z~2 must ...
... • Three of the four prior examples employed mm (PdBI) interferometer observations as well as VLA. • The rise of ALMA will strengthen this complementarity, with stellar scientific results. • New example – Wagg and Carilli combine VLA and ALMA for early forming galaxies: – Massive galaxies at z~2 must ...
X-ray activity cycle on the active ultra
... stellar activity to also monitor the solar activity-cycle in integrated light and showed that the so-called S-index of the Sun varies between 0.16 and 0.22 between its activity minima and maxima; in fact, the Sun shows one of the most regular cycles in the whole stellar sample presented by Baliunas ...
... stellar activity to also monitor the solar activity-cycle in integrated light and showed that the so-called S-index of the Sun varies between 0.16 and 0.22 between its activity minima and maxima; in fact, the Sun shows one of the most regular cycles in the whole stellar sample presented by Baliunas ...
FY1995 Q1 Oct-Dec NO.. - National Optical Astronomy Observatory
... Globular clusters are typically characterized by a single abundance of heavy metals: the fraction of heavy elements compared to hydrogen is constant from star to star. This suggests that the cluster formation was rapid, occurring in less than the characteristic time for heavy metal enrichment by Typ ...
... Globular clusters are typically characterized by a single abundance of heavy metals: the fraction of heavy elements compared to hydrogen is constant from star to star. This suggests that the cluster formation was rapid, occurring in less than the characteristic time for heavy metal enrichment by Typ ...
DEPOLARIZATION OF RADIO BURSTS DUE TO REFLECTION OFF
... Depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the corona is much more highly and sharply structured than can be resolved from o ...
... Depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the corona is much more highly and sharply structured than can be resolved from o ...
No Slide Title
... One neutrino is created for each 13 MeV of thermal energy The “Solar Constant”, S (Flux of solar radiation at Earth) is S 1.37 106 erg/cm2s Neutrino flux at Earth, φν, ...
... One neutrino is created for each 13 MeV of thermal energy The “Solar Constant”, S (Flux of solar radiation at Earth) is S 1.37 106 erg/cm2s Neutrino flux at Earth, φν, ...
The origin of the strongest magnetic fields in dwarfs
... 2.2 Selection effects owing to differences in mass Decided differences are apparent in the fraction of white dwarfs that are magnetic between the apparent magnitude-limited and the volume-limited sample. In the Palomar Green sample, an example of the former, only 2% are strongly magnetic. In the Hol ...
... 2.2 Selection effects owing to differences in mass Decided differences are apparent in the fraction of white dwarfs that are magnetic between the apparent magnitude-limited and the volume-limited sample. In the Palomar Green sample, an example of the former, only 2% are strongly magnetic. In the Hol ...
Stellar coronal response to differential rotation and flux emergence
... period (Pallavicini et al. 1981; Walter & Bowyer 1981), as do chromospheric emission proxies (Middelkoop 1981; Mekkaden 1985). Similarly, the mean surface field strength, B, is found to increase with decreasing rotation period (Vidotto et al. 2014). In addition to the activity–rotation relation, t ...
... period (Pallavicini et al. 1981; Walter & Bowyer 1981), as do chromospheric emission proxies (Middelkoop 1981; Mekkaden 1985). Similarly, the mean surface field strength, B, is found to increase with decreasing rotation period (Vidotto et al. 2014). In addition to the activity–rotation relation, t ...
Astrospheres and Solar-like Stellar Winds | SpringerLink
... contaminated by very broad, saturated H I absorption. For a long time, this absorption was assumed to be entirely from interstellar H I. However, for some of the nearest stars, the interstellar medium (ISM) cannot account for all of the observed absorption. With the assistance of complex hydrodynami ...
... contaminated by very broad, saturated H I absorption. For a long time, this absorption was assumed to be entirely from interstellar H I. However, for some of the nearest stars, the interstellar medium (ISM) cannot account for all of the observed absorption. With the assistance of complex hydrodynami ...
Effects of neutron-star superconductivity on
... The separation between nuclei is only a few fermis larger than the nuclear diameter, so the nuclei almost touch each other. There is a first-order phase change at about this density at which the nuclei "dissolve. "' At higher densities, deeper within the star, protons are continuously distributed wi ...
... The separation between nuclei is only a few fermis larger than the nuclear diameter, so the nuclei almost touch each other. There is a first-order phase change at about this density at which the nuclei "dissolve. "' At higher densities, deeper within the star, protons are continuously distributed wi ...
X-Ray Spectroscopy of Stars
... Stars are among the most prominent sources accessible to modern X-ray telescopes. In fact, stars located across almost all regions of a Hertzsprung-Russell diagram have been identified as X-ray sources, with only a few exceptions, most notably A-type stars and the coolest giants of spectral type M. ...
... Stars are among the most prominent sources accessible to modern X-ray telescopes. In fact, stars located across almost all regions of a Hertzsprung-Russell diagram have been identified as X-ray sources, with only a few exceptions, most notably A-type stars and the coolest giants of spectral type M. ...
X-ray Observations of Cosmic Accelerators Greg Madejski SLAC/KIPAC
... • Why the X-ray band? Motivation and brief history • Tools of X-ray astronomy: detectors and telescopes • Observations: Zoo of X-ray sources in the sky • Case studies and “X-ray insights” into the questions of particle acceleration in the cosmos: today - supernova remnants and X-ray binaries ...
... • Why the X-ray band? Motivation and brief history • Tools of X-ray astronomy: detectors and telescopes • Observations: Zoo of X-ray sources in the sky • Case studies and “X-ray insights” into the questions of particle acceleration in the cosmos: today - supernova remnants and X-ray binaries ...
on the rotational dynamics of magnetically threaded disks around
... flow, artificial in the sense that the angular motion could easily be modified by the huge viscous stress estimated for the inner parts of the disk. For a disk around a nonmagnetized star, Glatzel (1992) solved this problem without making the assumption that the rotation rate is Keplerian except in ...
... flow, artificial in the sense that the angular motion could easily be modified by the huge viscous stress estimated for the inner parts of the disk. For a disk around a nonmagnetized star, Glatzel (1992) solved this problem without making the assumption that the rotation rate is Keplerian except in ...
Dynamical response of magnetic tubes to transverse
... Various tubes with plasma β ranging from 0.1 to 10 embedded in a uniform nonmagnetic atmosphere are considered. High spatial resolution was obtained by the application of a multiple nested grid strategy. Various kinds of internal longitudinal and transverse body waves as well as surface waves were f ...
... Various tubes with plasma β ranging from 0.1 to 10 embedded in a uniform nonmagnetic atmosphere are considered. High spatial resolution was obtained by the application of a multiple nested grid strategy. Various kinds of internal longitudinal and transverse body waves as well as surface waves were f ...
ASI 2017 Abstract Book - Astronomical Society of India
... One of the most outstanding challenges in extragalactic astronomy is to identify the astrophysical processes responsible for transforming simple dark matter haloes into the heterogenous population of galaxies inhabiting today's Universe. How did different morphological types form and evolve? Does th ...
... One of the most outstanding challenges in extragalactic astronomy is to identify the astrophysical processes responsible for transforming simple dark matter haloes into the heterogenous population of galaxies inhabiting today's Universe. How did different morphological types form and evolve? Does th ...
L95 IRON-RICH EJECTA IN THE SUPERNOVA
... core X-ray emission (again outer and inner) were extracted. Background-subtracted count rates are given in Table 1. Background represented less than 0.5% of the source count rate in the 0.2–5 keV band as taken from a 1⬘–2⬘ annulus outside the remnant. Before fitting, source spectra were rebinned to ...
... core X-ray emission (again outer and inner) were extracted. Background-subtracted count rates are given in Table 1. Background represented less than 0.5% of the source count rate in the 0.2–5 keV band as taken from a 1⬘–2⬘ annulus outside the remnant. Before fitting, source spectra were rebinned to ...
The Solar Tachocline: A Self-Consistent Model of Magnetic
... high pressure and temperature cause hydrogen nuclei to fuse into helium, releasing the energy that powers the Sun (and all life on Earth). The thermal energy released in the core is carried outward by photon radiation. Throughout the solar interior, pressure, density and temperature all decrease out ...
... high pressure and temperature cause hydrogen nuclei to fuse into helium, releasing the energy that powers the Sun (and all life on Earth). The thermal energy released in the core is carried outward by photon radiation. Throughout the solar interior, pressure, density and temperature all decrease out ...
Evolution of magnetic helicity in the course of kinetic magnetic
... E · B = 0, the helicity is still approximately conserved if the non ideal reconnection zone is small, as compared to the length scale of the magnetic structure. In general, however, a non vanishing E · B may be a source for helicity production (Hornig and Rastätter, 1997). These investigations, wh ...
... E · B = 0, the helicity is still approximately conserved if the non ideal reconnection zone is small, as compared to the length scale of the magnetic structure. In general, however, a non vanishing E · B may be a source for helicity production (Hornig and Rastätter, 1997). These investigations, wh ...
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.