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pptx
pptx

... In order to fuse hydrogen, the center of a star must be hot enough. If a star’s mass is too low, its core will be too cool to ignite hydrogen fusion. These stars that are too small in mass for hydrogen fusion are called brown dwarfs. After their birth, they become steadily cooler, fainter, and small ...
The Solar System 2003
The Solar System 2003

... Apart from the eight planets in the Solar System, there is also known a few hundreds of extrasolar planets, which orbit foreign stars. Contemporary astronomical instruments do not allow to observe these distant planets directly, but their properties are calculated from photometric and astrometric m ...
stars - allenscience
stars - allenscience

... These celestial objects are extremely dense (a lot of matter in a very small volume). ...
Habitibility of Earth, in our Solar System, and Beyond
Habitibility of Earth, in our Solar System, and Beyond

Homework 4
Homework 4

... 1. If a protostar is forming out of a cold molecular cloud, how can its luminosity be upto one hundred times as large as the luminosity of the star it will become? ...
PLANETS OF THE DOUBLE SUN - Space Frontier Foundation
PLANETS OF THE DOUBLE SUN - Space Frontier Foundation

Lecture 27 (pdf from the powerpoint)
Lecture 27 (pdf from the powerpoint)

... •fp = the fraction of those stars which have planets •Estimated by Drake as 0.5. It is now known from modern planet searches that at least 10% of sunlike stars have planets, and the true proportion may be much higher, since only planets gas-giant size and larger can be detected with current technolo ...
Collapse: Method 2
Collapse: Method 2

... critical mass – the Jeans mass (after Sir James Jeanss (1877-1946) - it collapses to form a star. Gas and dust are then pulled together by gravity until a star is formed. ...
ph600-12 - University of Kent
ph600-12 - University of Kent

... a singular isothermal sphere as the initial state of the core that undergoes collapse, as described by Shu. We include the evolution of a first hydrostatic core at early times and allow a disk to grow, as predicted by Adams & Shu. We use a onedimensional radiative transfer code to calculate the spec ...
AST 301 Fall 2007 AST 301: Review for Exam 3 This exam covers
AST 301 Fall 2007 AST 301: Review for Exam 3 This exam covers

INV 12B MOTION WITH CHANGING SPEED DRY LAB DATA
INV 12B MOTION WITH CHANGING SPEED DRY LAB DATA

... c. unit used to measure the distance inside our solar system d. process in which volcanic eruptions release gas to the early atmosphere e. galaxy we are in f. the only planet with Goldilocks conditions g. planet with hot, heavily-cratered surface h. space object that causes craters i. the force that ...
Sample multiple choice questions for Exam 3
Sample multiple choice questions for Exam 3

The Drake Equation
The Drake Equation

ppt-file 2.4 MB
ppt-file 2.4 MB

... To try to pin down the locations of planets that might host life, Franck and Manfred Cuntz, an astrophyicist at the University of Texas in Arlington, used a mathematical model to locate the 'habitable zone' of 47 UMa, a Sun-like star some 45 light years away. The pair devised equations coupling stel ...
3A8d
3A8d

... An underlying theme throughout the course was the comparison of observed properties of galaxies with expectations from the current ΛCDM hierarchical model, which integrates a picture for the growth of galaxies with the buildup of the large scale structure of the Universe itself. (a) Describe, in rou ...
Bella Nicole and Calli
Bella Nicole and Calli

... The Solar System began 5 billion years ago. There were 9 planets, but scientists think Pluto should not be considered a planet anymore. A solar system is the Sun and the group of planets and bodies that orbit around it. ...
ppt - UCSB Physics
ppt - UCSB Physics

... except satellites, in our Solar System be defined into three distinct categories in the following way: – (1) A planet is a celestial body that • (a) is in orbit around the Sun, • (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium ( ...
Origins - UCSB Physics
Origins - UCSB Physics

... except satellites, in our Solar System be defined into three distinct categories in the following way: –  (1) A planet is a celestial body that •  (a) is in orbit around the Sun, •  (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibriu ...
Planet Formation
Planet Formation

The Sun and the Origin of the Solar System
The Sun and the Origin of the Solar System

... Starting point: – A cloud of interstellar gas and dust, the "solar nebula“ – Most of it (98%) is hydrogen and helium, includes dust grains of heavier material, formed in previous generations of stars. ...
Our Solar System - sci9sage-wmci
Our Solar System - sci9sage-wmci

... formation. He believes the nebular theory does not explain the formation of the planets Uranus and Neptune. Although these planets are considered gas giants, they both have large rock and ice cores with a thin gas layer. ...
Round 1
Round 1

Can you write numbers in scientific notation
Can you write numbers in scientific notation

... lecture/discussion, which may include additional material not found within this review sheet. Star Properties Are you familiar with how astronomers use solar units as a way of describing physical qualities of other stars? Do you know the surface temperature, total lifespan, and general composition o ...
Summing up the solar system
Summing up the solar system

... Jupiter, which was also thought to be a storm Uranus & Neptune are about the same size Jupiter is the largest planet ...
Solar system formation by accretion has no observational evidence
Solar system formation by accretion has no observational evidence

... circumsolar dust were attributed to sun-grazing comets. Thus, dust from the nebula was absent, suggesting that there had been no nebula. On the other hand, observations of debris formation are common in astronomy, especially in cases of stellar instability discussed below. The cosmos seems to be und ...
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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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