The Alpha Centauri binary system
... published analyses of its atmospheric parameters and abundances. Aims. We compare the many published analyses of the system, and attempt to resolve the significant discrepancies still extant in the determinations of the atmospheric parameters and abundances of these stars. Methods. We report a detai ...
... published analyses of its atmospheric parameters and abundances. Aims. We compare the many published analyses of the system, and attempt to resolve the significant discrepancies still extant in the determinations of the atmospheric parameters and abundances of these stars. Methods. We report a detai ...
Isotopic composition of Hg and Pt in 5 slowly rotating HgMn stars *
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
ASTRONOMY AND ASTROPHYSICS (ASTRO)
... and sources of opacity. Non-LTE and statistical equilibrium. Line profiles. Interpretation of stellar spectra: temperature, pressure, and abundance determinations. Stellar evolution from formation to final phases. ASTRO 582: High Energy Astrophysics (3-0) Cr. 3. Alt. F., offered even-numbered years. ...
... and sources of opacity. Non-LTE and statistical equilibrium. Line profiles. Interpretation of stellar spectra: temperature, pressure, and abundance determinations. Stellar evolution from formation to final phases. ASTRO 582: High Energy Astrophysics (3-0) Cr. 3. Alt. F., offered even-numbered years. ...
Chemical abundances and winds of massive stars in M31: a B
... in the OB 10 association of our nearest giant spiral, Andromeda (= M31 = NGC 224). OB 10 (van den Bergh 1964, Massey et al. 1986) is located at 23.6’ from the centre of M31, and has an apparent size of 2×1.0′ . Assuming a distance to M31 of 783 kpc (Holland 1998, Stanek & Garnavich 1998, assumed thr ...
... in the OB 10 association of our nearest giant spiral, Andromeda (= M31 = NGC 224). OB 10 (van den Bergh 1964, Massey et al. 1986) is located at 23.6’ from the centre of M31, and has an apparent size of 2×1.0′ . Assuming a distance to M31 of 783 kpc (Holland 1998, Stanek & Garnavich 1998, assumed thr ...
Brochure - Institut für Raumfahrtsysteme
... dust populations improves our understanding of its origins. Obvious evidence of dust in interplanetary space is the Zodiacal light, visible as a faint glow along the ecliptic after sunset or before dawn (Fig. 7). It is due to the reflection of sunlight by dust particles. The glow is concentrated in ...
... dust populations improves our understanding of its origins. Obvious evidence of dust in interplanetary space is the Zodiacal light, visible as a faint glow along the ecliptic after sunset or before dawn (Fig. 7). It is due to the reflection of sunlight by dust particles. The glow is concentrated in ...
Tracing the Evolution and Impact of the Stellar Winds
... layout is one of the unique flavors of the echelle spectroscopy technique that is necessitated by the peculiarity of its diffraction grating. A diffraction grating diffracts different wavelengths of light in particular directions, and one of its defining characteristics is the spacing between the sl ...
... layout is one of the unique flavors of the echelle spectroscopy technique that is necessitated by the peculiarity of its diffraction grating. A diffraction grating diffracts different wavelengths of light in particular directions, and one of its defining characteristics is the spacing between the sl ...
The local spiral structure of the Milky Way
... main arc of the Local Arm. Instead, these sources, as well as G059.78+00.06 and ON 1, branch off and curve inward in the Milky Way. As the dotted line in Fig. 2 suggests, these sources trace what appears to be a high-inclination spur bridging the Local Arm to the Sagittarius Arm near l ≈ 50°. Additi ...
... main arc of the Local Arm. Instead, these sources, as well as G059.78+00.06 and ON 1, branch off and curve inward in the Milky Way. As the dotted line in Fig. 2 suggests, these sources trace what appears to be a high-inclination spur bridging the Local Arm to the Sagittarius Arm near l ≈ 50°. Additi ...
9th Conference of Hel.A.S. Athens, 20
... A common acceleration process downstream of (quasi-perpendicular) CIR reverse shocks, planetary bow shocks and the termination shock The January 17, 2005 complex radio event (CME- CME interaction) Metric radio bursts and fine structures observed on 20 January, 2005 Combining ground-based and space m ...
... A common acceleration process downstream of (quasi-perpendicular) CIR reverse shocks, planetary bow shocks and the termination shock The January 17, 2005 complex radio event (CME- CME interaction) Metric radio bursts and fine structures observed on 20 January, 2005 Combining ground-based and space m ...
Neutrino Astrophysics
... The Sun belongs to a class of “main sequence” stars that derive their energy from burning protons to He in their cores. The SSM employs the standard theory of main-sequence stellar evolution, calibrated by the many detailed measurements only possible for the Sun, to follow the Sun from the onset of ...
... The Sun belongs to a class of “main sequence” stars that derive their energy from burning protons to He in their cores. The SSM employs the standard theory of main-sequence stellar evolution, calibrated by the many detailed measurements only possible for the Sun, to follow the Sun from the onset of ...
Particle kinematics in solar flares: observations - ETH E
... the closest in our universe. The Sun is the only star of which the surface can be spatially resolved in detail by direct observations, allowing us to study fine structures as small as several hundred kilometers. Further, it is constantly monitored by both, ground based and space born instruments whi ...
... the closest in our universe. The Sun is the only star of which the surface can be spatially resolved in detail by direct observations, allowing us to study fine structures as small as several hundred kilometers. Further, it is constantly monitored by both, ground based and space born instruments whi ...
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 ...
THE PRIMORDIAL HELIUM ABUNDANCE Manuel Peimbert
... the values computed by Smits (36) and Benjamin, Skillman, & Smits (37); (c) in hightemperature H II regions, the hydrogen Balmer lines can be excited by collisions of neutral atoms with free electrons, this effect is generally small, usually contributing less than a few percent of the intensity of H ...
... the values computed by Smits (36) and Benjamin, Skillman, & Smits (37); (c) in hightemperature H II regions, the hydrogen Balmer lines can be excited by collisions of neutral atoms with free electrons, this effect is generally small, usually contributing less than a few percent of the intensity of H ...
THE CASSINI VISUAL AND INFRARED MAPPING SPECTROMETER
... The Cassini VIMS instrument has its roots in a long line of proposed imaging spectrometers, starting with a rudimentary instrument proposed for the Lunar Polar Orbiter in 1974. A more refined concept was proposed for the Mariner Jupiter Uranus (MJU) mission in 1975. This design was accepted for the ...
... The Cassini VIMS instrument has its roots in a long line of proposed imaging spectrometers, starting with a rudimentary instrument proposed for the Lunar Polar Orbiter in 1974. A more refined concept was proposed for the Mariner Jupiter Uranus (MJU) mission in 1975. This design was accepted for the ...
Presolar History Recorded in Extraterrestrial Materials
... The study of presolar grains is also a story of technological advances. Traditional laboratory methods, such as thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry, only allow for the study of bulk samples. Yet key to constraining the stellar sources of these grains ...
... The study of presolar grains is also a story of technological advances. Traditional laboratory methods, such as thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry, only allow for the study of bulk samples. Yet key to constraining the stellar sources of these grains ...
File
... larger in diameter than Earth. You can measure the Sun’s mass using Newton’s version of Kepler’s third law. It is about 2 ⫻ 1030 kilograms, which is some 300,000 times the mass of Earth and nearly 1000 times the mass of all the planets in our solar system put together. You can observe the Sun’s rota ...
... larger in diameter than Earth. You can measure the Sun’s mass using Newton’s version of Kepler’s third law. It is about 2 ⫻ 1030 kilograms, which is some 300,000 times the mass of Earth and nearly 1000 times the mass of all the planets in our solar system put together. You can observe the Sun’s rota ...
The energy spectrum of cosmic electrons measured with the MAGIC
... of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from such distances. In particular the cosmic electrons on which this thesis will focus, reach Earth from much smaller distances. This is due to the strong energy losses they undergo in the magnetic f ...
... of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from such distances. In particular the cosmic electrons on which this thesis will focus, reach Earth from much smaller distances. This is due to the strong energy losses they undergo in the magnetic f ...
Presolar Cloud Collapse and the Formation and Early Evolution of
... motions develop and soon result in the formation of an optically thick first core, with a size on the order of 10 AU. This central core is supported primarily by the thermal pressure of the molecular hydrogen gas, while the remainder of the cloud continues to fall onto the core. For a 1 M cloud, thi ...
... motions develop and soon result in the formation of an optically thick first core, with a size on the order of 10 AU. This central core is supported primarily by the thermal pressure of the molecular hydrogen gas, while the remainder of the cloud continues to fall onto the core. For a 1 M cloud, thi ...
A COMPREHENSIVE COMPARISON OF THE SUN TO
... that life needs nothing special from its host star and would support the idea that life may be common in the universe. More particularly, if there is nothing special about the Sun, we have little reason to limit our life-hunting efforts to planets orbiting Sunlike stars. As an example of the type of ...
... that life needs nothing special from its host star and would support the idea that life may be common in the universe. More particularly, if there is nothing special about the Sun, we have little reason to limit our life-hunting efforts to planets orbiting Sunlike stars. As an example of the type of ...
Advanced Composition Explorer
Advanced Composition Explorer (ACE) is a NASA Explorers program Solar and space exploration mission to study matter comprising energetic particles from the solar wind, the interplanetary medium, and other sources. Real-time data from ACE is used by the NOAA Space Weather Prediction Center to improve forecasts and warnings of solar storms. The ACE robotic spacecraft was launched August 25, 1997 and entered a Lissajous orbit close to the L1 Lagrangian point (which lies between the Sun and the Earth at a distance of some 1.5 million km from the latter) on December 12, 1997. The spacecraft is currently operating at that orbit. Because ACE is in a non-Keplerian orbit, and has regular station-keeping maneuvers, the orbital parameters at right are only approximate. The spacecraft is still in generally good condition in 2015, and is projected to have enough fuel to maintain its orbit until 2024. NASA Goddard Space Flight Center managed the development and integration of the ACE spacecraft.