Galactic Evolution of Silicon Isotopes: Application to Presolar SiC
... more AGB stars seeding a cloud with SiC grains. Should SiC grains survive longer than the 108 yr lifetime of a cloud (say 109 yr), another factor of ten is gained, and the number of AGB stars seeding a cloud with SiC grains is 5000 times greater than the canonical estimate given above. Either way, t ...
... more AGB stars seeding a cloud with SiC grains. Should SiC grains survive longer than the 108 yr lifetime of a cloud (say 109 yr), another factor of ten is gained, and the number of AGB stars seeding a cloud with SiC grains is 5000 times greater than the canonical estimate given above. Either way, t ...
2013. CCAT. All Rights Reserved.
... We are developing X-Spec, a multi-object wide-band direct-detection spectrometer for CCAT. X-Spec is designed for rapid full-band (195-510 GHz), moderate resolution (R~700) spectral surveys of galaxies, measuring the bright atomic fine-structure and molecular rotational transitions which cool the in ...
... We are developing X-Spec, a multi-object wide-band direct-detection spectrometer for CCAT. X-Spec is designed for rapid full-band (195-510 GHz), moderate resolution (R~700) spectral surveys of galaxies, measuring the bright atomic fine-structure and molecular rotational transitions which cool the in ...
Galactic Evolution of Silicon Isotopes: Applications to
... We calculate and discuss the chemical evolution of the isotopic silicon abundances in the interstellar medium (ISM) at distances and times appropriate to the birth of the solar system. This has several objectives, some of which are related to anomalous silicon isotope ratios within presolar grains e ...
... We calculate and discuss the chemical evolution of the isotopic silicon abundances in the interstellar medium (ISM) at distances and times appropriate to the birth of the solar system. This has several objectives, some of which are related to anomalous silicon isotope ratios within presolar grains e ...
![Cosmic variance in [O/Fe] in the Galactic disk](http://s1.studyres.com/store/data/014331057_1-996ec6eddf93071c5e835624d4620c7e-300x300.png)
Cosmic variance in [O/Fe] in the Galactic disk
... We examine the distribution of the [O/Fe] abundance ratio in stars across the Galactic disk using H-band spectra from the Apache Point Galactic Evolution Experiment (APOGEE). We minimize systematic errors by considering groups of stars with similar atmospheric parameters. The APOGEE measurements in ...
... We examine the distribution of the [O/Fe] abundance ratio in stars across the Galactic disk using H-band spectra from the Apache Point Galactic Evolution Experiment (APOGEE). We minimize systematic errors by considering groups of stars with similar atmospheric parameters. The APOGEE measurements in ...
Powerpoint slides - Earth & Planetary Sciences
... estimates of nebular composition are correct F.Nimmo EART164 Spring 11 ...
... estimates of nebular composition are correct F.Nimmo EART164 Spring 11 ...
Analytic Models for the Mechanical Structure of the Solar Core
... Sun. Figures 2(a,b), 3(a,b) respectively show the ρ and P/ρ profiles for the BP98 ZAMS and present standard solar models (Pinsonneault 1998), which include helium and metal diffusion, both normalized to central values. These figures also show our fits to the ZAMS (present) SSM cores derived from our ...
... Sun. Figures 2(a,b), 3(a,b) respectively show the ρ and P/ρ profiles for the BP98 ZAMS and present standard solar models (Pinsonneault 1998), which include helium and metal diffusion, both normalized to central values. These figures also show our fits to the ZAMS (present) SSM cores derived from our ...
A Perspective from Extinct Radionuclides on a Young
... Sm (t1/2 = 103 Myr), were inherited from the long-term chemical evolution of the Galaxy (Clayton 1988, Nittler & Dauphas 2006). Others, such as 26 Al (t1/2 = 0.717 Myr), were produced in one or several nearby stars and were mixed with solar system material shortly before formation of planetary bodie ...
... Sm (t1/2 = 103 Myr), were inherited from the long-term chemical evolution of the Galaxy (Clayton 1988, Nittler & Dauphas 2006). Others, such as 26 Al (t1/2 = 0.717 Myr), were produced in one or several nearby stars and were mixed with solar system material shortly before formation of planetary bodie ...
large particles in active asteroid p/2010 a2
... We computed models to follow the motion of spherical particles (density ρ = 3000 kg m−3 ) under the action of solar gravity and radiation pressure. In these models, the ratio of the radiation pressure acceleration to gravitational acceleration is β = 0.2 aµ−1 , where aµ is the particle radius in mic ...
... We computed models to follow the motion of spherical particles (density ρ = 3000 kg m−3 ) under the action of solar gravity and radiation pressure. In these models, the ratio of the radiation pressure acceleration to gravitational acceleration is β = 0.2 aµ−1 , where aµ is the particle radius in mic ...
Wind Loading of Large Telescopes
... Seeing and buffeting • wind helps to mitigate thermally-induced local seeing • wind buffeting affects pointing and tracking and causes localized deformations of mirrors ...
... Seeing and buffeting • wind helps to mitigate thermally-induced local seeing • wind buffeting affects pointing and tracking and causes localized deformations of mirrors ...
Infrared Solar Physics - National Optical Astronomy Observatory
... and many of those observations have produced breakthrough science. But one thing is certain: the Sun is still stubbornly keeping secrets from us. The goal of this review is to clearly show how we can attack those outstanding questions in solar physics by looking through the window provided by the in ...
... and many of those observations have produced breakthrough science. But one thing is certain: the Sun is still stubbornly keeping secrets from us. The goal of this review is to clearly show how we can attack those outstanding questions in solar physics by looking through the window provided by the in ...
POISE AND EVOLUTION OF THE GALAXY : STRUCTURE ,
... reconstituted shape is by no way exceptional : quite a lot of galaxies, probably spiral as seen edgeon, in profile, indeed, display such a sandwich structure in direct observation, through the lengthy side (ex. : M104 , ESO510 , NGC 678/ 891 / 4013 / 4565 / 5866/ 7814 …) [Fig. 1b, 1c] . Even the dis ...
... reconstituted shape is by no way exceptional : quite a lot of galaxies, probably spiral as seen edgeon, in profile, indeed, display such a sandwich structure in direct observation, through the lengthy side (ex. : M104 , ESO510 , NGC 678/ 891 / 4013 / 4565 / 5866/ 7814 …) [Fig. 1b, 1c] . Even the dis ...
Unravelling the Origin and Evolution of Our Galaxy
... Approximately one-half of all spiral galaxies have discs that warp significantly out of the plane defined by the inner galaxy. Remarkably, there is no realistic explanation of this common phenomenon, though the large-scale structure of the dark matter, and tidal interactions, must be important, as t ...
... Approximately one-half of all spiral galaxies have discs that warp significantly out of the plane defined by the inner galaxy. Remarkably, there is no realistic explanation of this common phenomenon, though the large-scale structure of the dark matter, and tidal interactions, must be important, as t ...
UNIVERSITÀ DEGLI STUDI DI PADOVA Tesi di
... to direct solar radiation to a single linear elevated xed receiver. The rst to apply this principle in a real system for solar collection was Francia (1968) who developed both linear and two axis tracking Fresnel re ector systems. One substantial di culty with the Linear Fresnel Re ector (LFR) tec ...
... to direct solar radiation to a single linear elevated xed receiver. The rst to apply this principle in a real system for solar collection was Francia (1968) who developed both linear and two axis tracking Fresnel re ector systems. One substantial di culty with the Linear Fresnel Re ector (LFR) tec ...
Differential rotation of the Sun
... The Sun has an equatorial rotation speed of ~2 km/s; its differential rotation implies that the angular velocity decreases with increased latitude. The poles make one rotation every 34.3 days and the equator every 25.05 days, as measured relative to distant stars (sidereal rotation). The highly turb ...
... The Sun has an equatorial rotation speed of ~2 km/s; its differential rotation implies that the angular velocity decreases with increased latitude. The poles make one rotation every 34.3 days and the equator every 25.05 days, as measured relative to distant stars (sidereal rotation). The highly turb ...
Is $^ 6$ Li in metal-poor halo stars produced in situ by solar
... Li abundance measured in that star. However, Lemoine et al. (1997) have questioned this result on the basis of the 6 Li production efficiency: assuming the flaring activity of the contemporary Sun for one billion years, they found the amount of flareproduced 6 Li to be negligible as compared with the ...
... Li abundance measured in that star. However, Lemoine et al. (1997) have questioned this result on the basis of the 6 Li production efficiency: assuming the flaring activity of the contemporary Sun for one billion years, they found the amount of flareproduced 6 Li to be negligible as compared with the ...
Thermal Convection, Magnetic Field, and Differential Rotation in
... Turbulent thermal convection fills the solar convection zone. Understanding thermal convection is crucial for the transport of energy and angular momentum, and the generation and the transport of magnetic field. The central interest in this thesis is the interaction of small- and large-scale convect ...
... Turbulent thermal convection fills the solar convection zone. Understanding thermal convection is crucial for the transport of energy and angular momentum, and the generation and the transport of magnetic field. The central interest in this thesis is the interaction of small- and large-scale convect ...
Powerpoint slides - UCLA - Earth, Planetary, and Space Sciences
... – the minimum mass solar nebula • This gives us a constraint on the initial nebula conditions e.g. how rapidly did its density fall off with distance? • The picture gets more complicated if the planets have moved . . . • The change in planetary compositions with distance gives us another clue – sili ...
... – the minimum mass solar nebula • This gives us a constraint on the initial nebula conditions e.g. how rapidly did its density fall off with distance? • The picture gets more complicated if the planets have moved . . . • The change in planetary compositions with distance gives us another clue – sili ...
Shock structure and ion dynamics
... ig. 6. Ion bulk parameters, normalized to their upstream vales, from simulation corresponding to Figure 4, calculated using ...
... ig. 6. Ion bulk parameters, normalized to their upstream vales, from simulation corresponding to Figure 4, calculated using ...
IATED_GomezdeCastro
... 1. To observe the highly collimated jets from young Solar Systems and determine the characteristic ejection time. How planets can be formed in such an active environment? Is the Sun a “normal” star? 2. To observe and determine how the Sun orbits around the Galactic Center. 3. Are the planetary syste ...
... 1. To observe the highly collimated jets from young Solar Systems and determine the characteristic ejection time. How planets can be formed in such an active environment? Is the Sun a “normal” star? 2. To observe and determine how the Sun orbits around the Galactic Center. 3. Are the planetary syste ...
Copyright 2004 Society of Photo-Optical Instrumentation Engineers. This
... The C-continuum measurements have the advantage of providing the effective area for nearly the entire Chandra energy band. But extreme care has to be taken for the data analysis and results evaluation details. Following issues has to be resolved and calculated correctly: • Pileup: Pileups occur whe ...
... The C-continuum measurements have the advantage of providing the effective area for nearly the entire Chandra energy band. But extreme care has to be taken for the data analysis and results evaluation details. Following issues has to be resolved and calculated correctly: • Pileup: Pileups occur whe ...
Artificial comets
... star, a “ball of gas” that constantly releases gas flows from its outer atmosphere – or solar wind - into space. When a comet is close to the Sun, gas particles within its nucleus are discharged and pushed in the opposite direction to the Sun by the solar wind. By the way, the ...
... star, a “ball of gas” that constantly releases gas flows from its outer atmosphere – or solar wind - into space. When a comet is close to the Sun, gas particles within its nucleus are discharged and pushed in the opposite direction to the Sun by the solar wind. By the way, the ...
Ultra-high-energy cosmic-rays
... One will need to significantly increase the statistics at the highest energies, where the number of sources within the GZK horizon is very limited, in order to isolate sources in the sky…! Major challenge for the coming years!! Glasgow, 13 Nov. 20012! ...
... One will need to significantly increase the statistics at the highest energies, where the number of sources within the GZK horizon is very limited, in order to isolate sources in the sky…! Major challenge for the coming years!! Glasgow, 13 Nov. 20012! ...
β-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N = 82
... predicted by the KTUY and DF3 mass models are very similar, our data indicate a failure of the second generation of gross theory (GT2) employed to calculate half-lives rather than to the KTUY mass model. The half-lives of the N ¼ 82 nuclei are of particular interest for probing shell model calculati ...
... predicted by the KTUY and DF3 mass models are very similar, our data indicate a failure of the second generation of gross theory (GT2) employed to calculate half-lives rather than to the KTUY mass model. The half-lives of the N ¼ 82 nuclei are of particular interest for probing shell model calculati ...
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.