- UCL Discovery
... The evolution of the Sun’s magnetic field with time is crucial to the understanding of solar activity, particularly in the context of the 11 year sunspot cycle. The Sun’s magnetic field undergoes an oscillation between a poloidal configuration at sunspot minimum and a toroidal configuration at sunsp ...
... The evolution of the Sun’s magnetic field with time is crucial to the understanding of solar activity, particularly in the context of the 11 year sunspot cycle. The Sun’s magnetic field undergoes an oscillation between a poloidal configuration at sunspot minimum and a toroidal configuration at sunsp ...
solar twins and solar analogues in galactic surveys
... we call a solar twin a star that has the same observed parameters as the Sun within its errors. These stars can be used as stand-in suns when doing observations, as normal night-time telescopes are not built to be pointed at the Sun. There have been many searches for these twins and every one of the ...
... we call a solar twin a star that has the same observed parameters as the Sun within its errors. These stars can be used as stand-in suns when doing observations, as normal night-time telescopes are not built to be pointed at the Sun. There have been many searches for these twins and every one of the ...
PDF file
... the stored huge energy is released into the solar atmosphere in a short time. As a result of the energy release, a lot of phenomena are observed in various wavelengths; ejections of plasma, post-flare loops, nonthermal emission from energetic particles, and so on. Magnetic reconnection is widely acc ...
... the stored huge energy is released into the solar atmosphere in a short time. As a result of the energy release, a lot of phenomena are observed in various wavelengths; ejections of plasma, post-flare loops, nonthermal emission from energetic particles, and so on. Magnetic reconnection is widely acc ...
the next decade - Lowell Observatory
... Today “Mount Wilson S” is universally recognized as a standard measure of stellar activity, but it contains a color term (due to its dependence on nearby continua) that render it unsuitable for direct physical comparison of stars of different temperature, or for interpretation in the context of abso ...
... Today “Mount Wilson S” is universally recognized as a standard measure of stellar activity, but it contains a color term (due to its dependence on nearby continua) that render it unsuitable for direct physical comparison of stars of different temperature, or for interpretation in the context of abso ...
SOFT X-RAY EMISSIONS FROM PLANETS, MOONS, AND COMETS
... by CXO to be a source of soft x-rays [9]. Though the xrays from Jupiter were discovered in 1979 by Einstein observatory [cf. Ref. 2], the recent high spatial resolution observations by CXO/HRC-I have revealed a mysterious pulsating (period ~45 minutes) x-ray hot spot in the northern polar regions o ...
... by CXO to be a source of soft x-rays [9]. Though the xrays from Jupiter were discovered in 1979 by Einstein observatory [cf. Ref. 2], the recent high spatial resolution observations by CXO/HRC-I have revealed a mysterious pulsating (period ~45 minutes) x-ray hot spot in the northern polar regions o ...
The Galactic Environment of the Sun
... moves with a speed of about 16.5 kilometers per second, or nearly 50 lightyears per million years. The sun’s path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of ...
... moves with a speed of about 16.5 kilometers per second, or nearly 50 lightyears per million years. The sun’s path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of ...
Thermal Convection, Magnetic Field, and Differential Rotation in
... details of the structure are controversial, the tachocline is thought to be ellipsoidal. For example, Charbonneau et al. (1999) show that the center of the tachocline is rt /R⊙ = 0.693 ± 0.003 at the equator which is below the base of the convection zone and rt /R⊙ = 0.717 ± 0.003 at the pole which ...
... details of the structure are controversial, the tachocline is thought to be ellipsoidal. For example, Charbonneau et al. (1999) show that the center of the tachocline is rt /R⊙ = 0.693 ± 0.003 at the equator which is below the base of the convection zone and rt /R⊙ = 0.717 ± 0.003 at the pole which ...
Powerpoint slides - Earth & Planetary Sciences
... • Which elements actually condense will depend on the local nebular conditions (temperature) • E.g. volatile species will only be stable beyond a “snow line”. This is why the inner planets are rock-rich and the outer planets gas- and ice-rich • The compounds formed from the elements will be determin ...
... • Which elements actually condense will depend on the local nebular conditions (temperature) • E.g. volatile species will only be stable beyond a “snow line”. This is why the inner planets are rock-rich and the outer planets gas- and ice-rich • The compounds formed from the elements will be determin ...
Oxygen and Neon Abundances of B-Type Stars in Comparison with
... To revisit the long-standing problem of a possible inconsistency concerning the oxygen composition in the current Galactic gas and in the solar atmosphere (i.e., the former being appreciably lower by 0.3 dex), apparently contradicting the Galactic chemical evolution, we carried out oxygen abundanc ...
... To revisit the long-standing problem of a possible inconsistency concerning the oxygen composition in the current Galactic gas and in the solar atmosphere (i.e., the former being appreciably lower by 0.3 dex), apparently contradicting the Galactic chemical evolution, we carried out oxygen abundanc ...
8th International Workshop on Planetary, Solar and Heliospheric
... starting at 8 PM as a kind of icebreaker party. The region of southern Styria is well-known for its excellent white wines, for example, wines from Erich and Walter Polz were served at the wedding dinner of Princess Madeleine of Sweden in 2013. The wines of “Schloss Seggau” are also produced by Erich ...
... starting at 8 PM as a kind of icebreaker party. The region of southern Styria is well-known for its excellent white wines, for example, wines from Erich and Walter Polz were served at the wedding dinner of Princess Madeleine of Sweden in 2013. The wines of “Schloss Seggau” are also produced by Erich ...
Magnetic quenching of turbulent diffusivity - Andrés Muñoz
... magnetic field to a narrow layer in the interface between the convection and radiative zones and its amplification to superequipartition values; Gilman & Rempel (2005) studied how quenching can contribute to the generation of strong superequipartition fields at the bottom of the convection zone, eve ...
... magnetic field to a narrow layer in the interface between the convection and radiative zones and its amplification to superequipartition values; Gilman & Rempel (2005) studied how quenching can contribute to the generation of strong superequipartition fields at the bottom of the convection zone, eve ...
Betelgeuse – Challenging our Understanding for more than 2000
... Abstract: AJ 65, 503 (1960); arVcle: ApJ 136, 844 (1962) ...
... Abstract: AJ 65, 503 (1960); arVcle: ApJ 136, 844 (1962) ...
Lecture Notes and Essays in Astrophysics VOLUME III
... thickness of the cloud layers and being representative of the mean particle size. This multilayered cloud structure implies a total optical depth at the surface of ∼ 30. VIRTIS observations depend strongly on the wavelength and three cloud layers are clearly observed with uncorrelated structures at ...
... thickness of the cloud layers and being representative of the mean particle size. This multilayered cloud structure implies a total optical depth at the surface of ∼ 30. VIRTIS observations depend strongly on the wavelength and three cloud layers are clearly observed with uncorrelated structures at ...
STELLAR ABLATION OF PLANETARY ATMOSPHERES
... and the heavy, gravitationally bound majority ion species, O+. The first definitive measurements of this classical light ion polar wind outflow were obtained by a polar orbiting satellite above 1000 km altitude in the early 1970s [Hoffman et al., 1974]. However, as a result of satellite measurements ...
... and the heavy, gravitationally bound majority ion species, O+. The first definitive measurements of this classical light ion polar wind outflow were obtained by a polar orbiting satellite above 1000 km altitude in the early 1970s [Hoffman et al., 1974]. However, as a result of satellite measurements ...
Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic
... Goedbloed & Poedts 2004). This would generalize the notion of a stellar dynamo as discussed by Parker (1975) for the convective envelope. This specific approach is however critiqued in recent papers by Denissenkov & Pinsonneault (2007) and Zahn et al. (2007). In the rest of this note, we do not adop ...
... Goedbloed & Poedts 2004). This would generalize the notion of a stellar dynamo as discussed by Parker (1975) for the convective envelope. This specific approach is however critiqued in recent papers by Denissenkov & Pinsonneault (2007) and Zahn et al. (2007). In the rest of this note, we do not adop ...
X-ray astronomy of stellar coronae (Review)
... with data from previous rocket flights, our modern picture of the solar and therefore stellar coronae. The solar X-ray corona is now understood as a dynamic ensemble of magnetic loops that contain hot plasma in ever-changing constellations, yet always related to the underlying photospheric magnetic ...
... with data from previous rocket flights, our modern picture of the solar and therefore stellar coronae. The solar X-ray corona is now understood as a dynamic ensemble of magnetic loops that contain hot plasma in ever-changing constellations, yet always related to the underlying photospheric magnetic ...
The Norman Lockyer plate archive collection
... (which I believe you also have?). It would be useful, for instance, to get a ball-park figure for how many plates there are in that collection, and to show (if you can) a slide or quick scan that demonstrates a 'typical' exposure (if there is such a thing). My own suggestion for that collection woul ...
... (which I believe you also have?). It would be useful, for instance, to get a ball-park figure for how many plates there are in that collection, and to show (if you can) a slide or quick scan that demonstrates a 'typical' exposure (if there is such a thing). My own suggestion for that collection woul ...
Laboratory Astrophysics: Spectral Analysis of Photoionized Neon J ames MacArthur
... or stellar black hole) accreting mass from its large companion (an 0 or B star - the most luminous types of star). The compact object accretes mass in two ways: stellar wind from the companion a falling on to the compact object, and Roche Lobe overflow. In HMXBs, there is a figure-8 shaped region bo ...
... or stellar black hole) accreting mass from its large companion (an 0 or B star - the most luminous types of star). The compact object accretes mass in two ways: stellar wind from the companion a falling on to the compact object, and Roche Lobe overflow. In HMXBs, there is a figure-8 shaped region bo ...
The magnetic field and wind confinement of b Cephei: new clues for
... literature for b Cep. We must therefore estimate these parameters based on measurements of normal non-supergiant B stars of similar spectral type, using for instance the survey of Prinja (1989). We first obtain that b Cep should have a terminal velocity of the order of the escape velocity (equal to ...
... literature for b Cep. We must therefore estimate these parameters based on measurements of normal non-supergiant B stars of similar spectral type, using for instance the survey of Prinja (1989). We first obtain that b Cep should have a terminal velocity of the order of the escape velocity (equal to ...
Laboratory Astrophysics: Spectral Analysis of Photoionized Neon
... 1.2, hotter plasmas would have a larger standard deviation in energy). When only photoexcitation is included (no ionizing photons are present in the model) in the middle pane on the left, the higher n transitions like β and γ are more pronounced, since their upper levels (the 1snp He-like levels wit ...
... 1.2, hotter plasmas would have a larger standard deviation in energy). When only photoexcitation is included (no ionizing photons are present in the model) in the middle pane on the left, the higher n transitions like β and γ are more pronounced, since their upper levels (the 1snp He-like levels wit ...
The solar silicon abundance based on 3D non
... less than 0.001 dex in the abundance corrections was determined by comparing the abundance corrections derived from the individual snapshots with the final value obtained after integrating over the selected snapshots. The 3D non-LTE calculations were performed for three silicon abundances: lg Si = ...
... less than 0.001 dex in the abundance corrections was determined by comparing the abundance corrections derived from the individual snapshots with the final value obtained after integrating over the selected snapshots. The 3D non-LTE calculations were performed for three silicon abundances: lg Si = ...
Growth of the inner core in the mean
... planet, can change spatial spectrum of the observable magnetic field. These more or less evident assumptions were already tested in some 3D models, however the obtained conclusions still can not provide the robust scenario of the core evolution, supported by the paleomagnetic measurements [Reshetnya ...
... planet, can change spatial spectrum of the observable magnetic field. These more or less evident assumptions were already tested in some 3D models, however the obtained conclusions still can not provide the robust scenario of the core evolution, supported by the paleomagnetic measurements [Reshetnya ...
white dwarf
... Polars: Synchronisation • All of the variability in Polars occurs at a single period: the orbital period – radial velocity curves of the secondary – X-ray light curves from the primary – polarisation variations the white dwarf/red dwarf are locked into the same orientation: synchronised rotation ...
... Polars: Synchronisation • All of the variability in Polars occurs at a single period: the orbital period – radial velocity curves of the secondary – X-ray light curves from the primary – polarisation variations the white dwarf/red dwarf are locked into the same orientation: synchronised rotation ...
Origin and evolution of magnetars
... observations of all magnetars with known Ṗ . Thus, among the observed objects we have also included SGR 0526−66, which is located in the LMC, and CXOU J010043−721134, which is in the SMC, since their positions in the P − Ṗ diagram are unlikely to depend on which galaxy they reside. The predicted n ...
... observations of all magnetars with known Ṗ . Thus, among the observed objects we have also included SGR 0526−66, which is located in the LMC, and CXOU J010043−721134, which is in the SMC, since their positions in the P − Ṗ diagram are unlikely to depend on which galaxy they reside. The predicted n ...
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.