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Astrology
Astrology

... • Sun sign compatibility? No correlation with 3000 couples marrying or 500 divorcing. • Choice of profession: No correlation with Sun sign for 6000 politicians or 17,000 scientists • Horoscope of mass murderer sent to 150 people. 94% said it described them well. • 3000 specific predictions about cel ...
Astrology
Astrology

... •  Sun sign compatibility? No correlation with 3000 couples marrying or 500 divorcing. •  Choice of profession: No correlation with Sun sign for 6000 politicians or 17,000 scientists •  Horoscope of mass murderer sent to 150 people. 94% said it described them well. •  3000 specific predictions about ...
View PDF
View PDF

... Some protoplanetary disks may spawn many carbon planets simply because they are especially rich in carbon overall, and planet formation proceeds by a carbon-rich condensation sequence. The planets around the pulsar PSR 1257+12 (Wolszczan & Frail 1992) might have been formed in a carbon-rich nebula c ...
Improving the Gaia planet catch by combining the astrometry with
Improving the Gaia planet catch by combining the astrometry with

On disc driven inward migration of resonantly coupled planets with
On disc driven inward migration of resonantly coupled planets with

... mass. The ratio of semi-major axes a1 /a2 of the planets decreases until the planets “lock” into a 2:1 commensurability with n2 ≈ 2n1 at a time t ≈ 400 orbits. Both planets then subsequently migrate inwards a further 10% maintaining this ratio, showing the resonance to be robust. Figure 1 also shows ...
The Galactic Halo The Galactic Disk Height and Thickness of MW
The Galactic Halo The Galactic Disk Height and Thickness of MW

... Shapley’s Center of the Galaxy " To find the center of the Galaxy, Shapley measured the distance to each cluster using RR Lyrae stars and produced a three dimensional plot of the clusters’ positions. The center of the Galaxy was then identified by the average position of the clusters. " We now know ...
Program and abstracts in one word document
Program and abstracts in one word document

... High contrast imaging: a view on extrasolar planetary systems beyond the snow line Although very successful (more than 350 planets discovered up to now) indirect methods for extrasolar planet detection (radial velocity, transits) are sensitive to planets quite close to their hosts. Moreover, accurat ...
Planetary Radii Across Five Orders of Magnitude in Mass and Stellar
Planetary Radii Across Five Orders of Magnitude in Mass and Stellar

... We are still in the early days of a revolution in the field of planetary sciences that was triggered by the discovery of planets around other stars. Exoplanets now number over 200, with masses as small as 5–7 M (Rivera et al. 2005; Beaulieu et al. 2006). Comparative planetology, which once include ...
hot CNO cycle
hot CNO cycle

... power is 8 x 1037 erg s-1, but only 1.3 x 1035 erg s-1 is escaping from the surface - small compared with the accretion luminosity. ...
Planetary Formation - Scholarly Commons @ Ouachita
Planetary Formation - Scholarly Commons @ Ouachita

... Follow this and additional works at: http://scholarlycommons.obu.edu/honors_theses Part of the Physical Processes Commons, and the The Sun and the Solar System Commons ...
Light: The Cosmic Messenger
Light: The Cosmic Messenger

arXiv:1502.04693v1 [gr
arXiv:1502.04693v1 [gr

PHYS3380_111115_bw - The University of Texas at Dallas
PHYS3380_111115_bw - The University of Texas at Dallas

Gilmore - Astrometry and Astrophysics in the Gaia sky
Gilmore - Astrometry and Astrophysics in the Gaia sky

... distances to 1% for 18 million stars to 2.5 kpc distances to 10% for 150 million stars to 25 kpc rare stellar types and rapid evolutionary phases in large numbers parallax calibration of all distance indicators e.g. Cepheids and RR Lyrae to LMC/SMC ...
Stars III The Hertzsprung
Stars III The Hertzsprung

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13.1 Introduction 13.2 The Red Giant Branch
13.1 Introduction 13.2 The Red Giant Branch

... phase is mass loss. As the stellar luminosity and radius increase while a star evolves along the giant branch, the envelope becomes loosely bound and it is relatively easy for the large photon flux to remove mass from the stellar surface via radiation pressure (Lecture 9.2.2) on atoms and grains. Gr ...
Formation, Habitability, and Detection of Extrasolar Moons
Formation, Habitability, and Detection of Extrasolar Moons

Insights into planet formation from debris disks: II. Giant impacts in
Insights into planet formation from debris disks: II. Giant impacts in

... The majority of the processes that contribute to the formation of a planetary system are thought to take place in the massive circumstellar disks that surround young stars called protoplanetary disks. Such disks last for up to around 10 Myr before dispersing through mechanisms that are still debated ...
Transit surveys for Earths in the habitable zones of white dwarfs
Transit surveys for Earths in the habitable zones of white dwarfs

... The search for habitable planets has focused on stars similar to the Sun as it is the sole example we have of a star with a habitable planet, and nuclear burning provides a long-lived source of energy (Kasting et al. 1993; Lunine et al. 2008). White dwarfs, which are as common as Sun-like stars, may ...
Pulsed  Accretion  in  the Young  Binary &
Pulsed Accretion in the Young Binary &

... low fractional levels over the course of 10 Myr or less. Accretion would also be enhanced by a smaller binary separation and a smaller orbital period (Ostriker et al. 1992). But recently, White and Ghez (2001) found that the mass accretion rates for primary stars are similar to single stars, which s ...
16_Testbank
16_Testbank

... cloud becomes so dense that the thermal radiation cannot escape, the temperature rises rapidly, nuclear fusion begins and the dense core becomes a protostar. As the cloud has collapsed from a large size to a small size, it must spin very fast to conserve angular momentum. This results in the formati ...
Untitled - METU Astrophysics Home Page
Untitled - METU Astrophysics Home Page

... calculations of neutron star mass and radii. However, the first observational evidence of a rotation powered pulsar hasn’t come until 1967, when Bell detected radio pulsations from outside the solar system which later was understood to be the first detection of a pulsar by the humankind. Following t ...
– 1 – 1. Nucleosynthetic Yields From Various Sources
– 1 – 1. Nucleosynthetic Yields From Various Sources

... searches. Thus it was believed that if PISN acutally occur, they would be confined to the early Universe, where 0 metallicity would permit such high mass stars to be formed and to evolve. Such stars, if present, would be tremendously important in chemical evolution because of the very large amount o ...
white dwarfs, neutron stars, black hole
white dwarfs, neutron stars, black hole

... our Sun. After the outer layers of the star have swollen into a red supergiant (i.e., a very big red giant), the core begins to yield to gravity and starts to shrink. As it shrinks, it grows hotter and denser, and a new series of nuclear reactions begin to occur, temporarily halting the collapse of ...
Astrophysical Conditions for Planetary Habitability - Max
Astrophysical Conditions for Planetary Habitability - Max

... remain speculative, however, until they are observed, and one would not want to count on their existence while defining the requirements for a telescope to search for extrasolar life (Kasting et al., 2014). Recently, Kopparapu et al. (2013) rederived the HZ boundaries using a new 1-D climate model b ...
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Nebular hypothesis

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System. It suggests that the Solar System formed from nebulous material. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heaven. Originally applied to our own Solar System, this process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular hypothesis is the solar nebular disk model (SNDM) or simply solar nebular model. This nebular hypothesis offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the nebular hypothesis are echoed in modern theories of planetary formation, but most elements have been superseded.According to the nebular hypothesis, stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC). These clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk around the young star. This may give birth to planets in certain circumstances, which are not well known. Thus the formation of planetary systems is thought to be a natural result of star formation. A Sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10-100 million years.The protoplanetary disk is an accretion disk that feeds the central star. Initially very hot, the disk later cools in what is known as the T tauri star stage; here, formation of small dust grains made of rocks and ice is possible. The grains eventually may coagulate into kilometer-sized planetesimals. If the disk is massive enough, the runaway accretions begin, resulting in the rapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos. Near the star, the planetary embryos go through a stage of violent mergers, producing a few terrestrial planets. The last stage takes approximately 100 million to a billion years.The formation of giant planets is a more complicated process. It is thought to occur beyond the so-called frost line, where planetary embryos mainly are made of various types of ice. As a result, they are several times more massive than in the inner part of the protoplanetary disk. What follows after the embryo formation is not completely clear. Some embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of the hydrogen–helium gas from the disk. The accumulation of gas by the core is initially a slow process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses (M⊕) it accelerates and proceeds in a runaway manner. Jupiter- and Saturn-like planets are thought to accumulate the bulk of their mass during only 10,000 years. The accretion stops when the gas is exhausted. The formed planets can migrate over long distances during or after their formation. Ice giants such as Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.
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