Growing the Terrestrial Planets from the Gradual
... shows the value of ξ in our fiducial disk (which is described in the Methods section) for two values of τ that are consistent with the requirements of the two competing models of planetesimal formation. In particular, the top panel employs τ = 0.1 pebbles that are required for the so-called streamin ...
... shows the value of ξ in our fiducial disk (which is described in the Methods section) for two values of τ that are consistent with the requirements of the two competing models of planetesimal formation. In particular, the top panel employs τ = 0.1 pebbles that are required for the so-called streamin ...
Exploring Comets
... 6. Comets have three parts: the nucleus, the coma and the tails. The nucleus is the solid center component made of ice, gas and rocky debris. The coma is the gas and dust atmosphere around the nucleus, which results when heat from the Sun warms the surface of the nucleus so that gas and dust spew fo ...
... 6. Comets have three parts: the nucleus, the coma and the tails. The nucleus is the solid center component made of ice, gas and rocky debris. The coma is the gas and dust atmosphere around the nucleus, which results when heat from the Sun warms the surface of the nucleus so that gas and dust spew fo ...
Full Paper - PDF - Armagh Observatory
... in view of his remarks about high orbital eccentricity, it seems more likely that he was envisaging a much more extended distribution of transneptunian objects. In this context, a popular article published by Frederick C. Leonard soon after the discovery of Pluto seems more à propos (Marsden, 2000). ...
... in view of his remarks about high orbital eccentricity, it seems more likely that he was envisaging a much more extended distribution of transneptunian objects. In this context, a popular article published by Frederick C. Leonard soon after the discovery of Pluto seems more à propos (Marsden, 2000). ...
The Primordial Excitation and Clearing of the Asteroid Belt
... completely formed. Note, however, that some of these objects could be fragments from gigantic collisions between embryos during the very early phases. The few large bodies that were destroyed generally yielded at most one large fragment (larger than 50 km), with mostly unchanged dynamical characteri ...
... completely formed. Note, however, that some of these objects could be fragments from gigantic collisions between embryos during the very early phases. The few large bodies that were destroyed generally yielded at most one large fragment (larger than 50 km), with mostly unchanged dynamical characteri ...
Other topics
... Divide the history of the asteroid belt into an early accretion phase followed by an extended depletion phase Bottke et al. (2005a,b) evolved the asteroid belt over billions of years, starting from a size distribution which matches the current one for bodies larger than 120 km in diameter ...
... Divide the history of the asteroid belt into an early accretion phase followed by an extended depletion phase Bottke et al. (2005a,b) evolved the asteroid belt over billions of years, starting from a size distribution which matches the current one for bodies larger than 120 km in diameter ...
Lesson Plan D2 Comets and Meteors
... awe and wonder. This exercise allows students to learn some basic facts about the nature of comets and how they orbit the Sun. ...
... awe and wonder. This exercise allows students to learn some basic facts about the nature of comets and how they orbit the Sun. ...
Project GLAD Adapted from Santa Ana Unified School District by
... one full year to travel around the sun. How many days and months does one year represent? Write your answer on the back. Axis is the point on which the earth spins or rotates. It takes the earth one day to rotate all the way around on its axis. The earth’s axis is the north and south pole. Make a sk ...
... one full year to travel around the sun. How many days and months does one year represent? Write your answer on the back. Axis is the point on which the earth spins or rotates. It takes the earth one day to rotate all the way around on its axis. The earth’s axis is the north and south pole. Make a sk ...
AST1001.ch9
... • Most have been discovered very recently so little is known about them. • NASA’s New Horizons mission will study Pluto and a few other Kuiper Belt Objects in a planned flyby. ...
... • Most have been discovered very recently so little is known about them. • NASA’s New Horizons mission will study Pluto and a few other Kuiper Belt Objects in a planned flyby. ...
AST1001.ch9
... • Most have been discovered very recently so little is known about them. • NASA’s New Horizons mission will study Pluto and a few other Kuiper Belt Objects in a planned flyby. ...
... • Most have been discovered very recently so little is known about them. • NASA’s New Horizons mission will study Pluto and a few other Kuiper Belt Objects in a planned flyby. ...
Theme 10.1 -- Leftovers: Comets
... Far away from the sun, however, the comet is completely inconspicuous and can be thought of as a “dirty snowball,” to use the phrase first introduced by astronomer Fred Whipple in the 1950s. The nucleus would be about 10 kilometres in diameter and consist of pebbles and small stones in a matrix of ...
... Far away from the sun, however, the comet is completely inconspicuous and can be thought of as a “dirty snowball,” to use the phrase first introduced by astronomer Fred Whipple in the 1950s. The nucleus would be about 10 kilometres in diameter and consist of pebbles and small stones in a matrix of ...
Primordial Excitation and Depletion of the Main Belt
... ones with a radial density profile of r –3/2 and a time decay, independent of r, governed only by e–t/t 0. Nonetheless, encouraging results followed: e values were pumped to likely levels, easily reaching 0.3 during nebula dissipation times in the range 104 < t 0 < 105 yr. During these times both ν5 ...
... ones with a radial density profile of r –3/2 and a time decay, independent of r, governed only by e–t/t 0. Nonetheless, encouraging results followed: e values were pumped to likely levels, easily reaching 0.3 during nebula dissipation times in the range 104 < t 0 < 105 yr. During these times both ν5 ...
lecture 3
... long-period comets requires that most new comets are destroyed after their first passage • formation efficiency is rather low – only about 3% for classical Oort cloud and another 3% in the inner cloud. Given current mass of about 5 M⊕ in the classical cloud, this requires 200M⊕ or more in residual ...
... long-period comets requires that most new comets are destroyed after their first passage • formation efficiency is rather low – only about 3% for classical Oort cloud and another 3% in the inner cloud. Given current mass of about 5 M⊕ in the classical cloud, this requires 200M⊕ or more in residual ...
Unit: Exploring Planetary Systems (Science/Grade 8)
... The Sun, planets, moons, comets, asteroids, and meteoroids in our solar system comprise a system of interacting bodies. The Sun is at the center of the solar system. Planets, asteroids, comets, and meteoroids orbit the Sun. Gravity is the force that keeps the planets in orbit around the Sun and gove ...
... The Sun, planets, moons, comets, asteroids, and meteoroids in our solar system comprise a system of interacting bodies. The Sun is at the center of the solar system. Planets, asteroids, comets, and meteoroids orbit the Sun. Gravity is the force that keeps the planets in orbit around the Sun and gove ...
The populations of comet-like bodies in the Solar system
... & Duncan 1997). Centaur orbits are typically planet-crossing and have relatively short dynamical lifetimes (∼106 yr). Chiron, which is one of a number of exceptionally large minor bodies with perihelia close to or within the orbit of Saturn, exhibits cometary activity (e.g. Luu & Jewitt 1990) and ev ...
... & Duncan 1997). Centaur orbits are typically planet-crossing and have relatively short dynamical lifetimes (∼106 yr). Chiron, which is one of a number of exceptionally large minor bodies with perihelia close to or within the orbit of Saturn, exhibits cometary activity (e.g. Luu & Jewitt 1990) and ev ...
Origin and Evolution of Trojan Asteroids
... The large discrepancies between some of these estimates might be due to some extent to the statistical limitations in the detection capabilities of the surveys. Bias correction for the selection effects in the observed populations is a difficult task, in particular for Trojans. Their librational mot ...
... The large discrepancies between some of these estimates might be due to some extent to the statistical limitations in the detection capabilities of the surveys. Bias correction for the selection effects in the observed populations is a difficult task, in particular for Trojans. Their librational mot ...
Comets - Helios
... Comets are generally named after their discoverers, e. g. Comet Hale-Bopp More and more comets are being found by automated ...
... Comets are generally named after their discoverers, e. g. Comet Hale-Bopp More and more comets are being found by automated ...
Jupiter - Friend or Foe
... The idea that Jupiter has protected the Earth from excessive bombardment dates back to when the main impact risk to the Earth was thought to arise from the Oort cloud comets. The idea probably dates back to the 1960s, when craters were first widely accepted as evidence of ongoing impacts upon the E ...
... The idea that Jupiter has protected the Earth from excessive bombardment dates back to when the main impact risk to the Earth was thought to arise from the Oort cloud comets. The idea probably dates back to the 1960s, when craters were first widely accepted as evidence of ongoing impacts upon the E ...
ori pro 02 semifin [sfn] - SwRI-Boulder`s
... Fernández & Ip (1984) showed that as the giant planets scattered residual planetesimals, Jupiter would have migrated inward and Saturn, Uranus, and Neptune would have migrated outward. In this process, the orbital separations of Jupiter and Saturn would have increased by ~1 AU (Malhotra 1995). Origi ...
... Fernández & Ip (1984) showed that as the giant planets scattered residual planetesimals, Jupiter would have migrated inward and Saturn, Uranus, and Neptune would have migrated outward. In this process, the orbital separations of Jupiter and Saturn would have increased by ~1 AU (Malhotra 1995). Origi ...
Jupiter – friend or foe? III: the Oort cloud comets
... massless particles, and were unable to gravitationally interact with each other. They felt the gravitational influence of the Sun, Jupiter and Saturn, but did not exert any force on those bodies. Whereas in Papers I and II we counted the number of collisions on an (inflated) Earth, for the Oort clo ...
... massless particles, and were unable to gravitationally interact with each other. They felt the gravitational influence of the Sun, Jupiter and Saturn, but did not exert any force on those bodies. Whereas in Papers I and II we counted the number of collisions on an (inflated) Earth, for the Oort clo ...
Astronomical Scale
... number is about 0.0000000004.4. Note that the units canceled each other out. This can be written in scientific notation as 4.4 X 10-10 or 4.4E-10, both of which are clearer to read. We will use 4.4E-10 because it is easier to type this number style into our calculators. Now that we have figured out ...
... number is about 0.0000000004.4. Note that the units canceled each other out. This can be written in scientific notation as 4.4 X 10-10 or 4.4E-10, both of which are clearer to read. We will use 4.4E-10 because it is easier to type this number style into our calculators. Now that we have figured out ...
Teacher Resource Guide - Sci-Port
... Dust Tail— This type of comet tail forms when the solar wind separates dust from the coma, pushing it outward away from the Sun in a slightly curved path. Formaldehyde (HCHO)— A chemical compound consisting of four atoms: two of hydrogen, one of carbon, and one of oxygen. At standard temperature and ...
... Dust Tail— This type of comet tail forms when the solar wind separates dust from the coma, pushing it outward away from the Sun in a slightly curved path. Formaldehyde (HCHO)— A chemical compound consisting of four atoms: two of hydrogen, one of carbon, and one of oxygen. At standard temperature and ...
Lecture 08
... The Asteroid with Our Name on It • We have found about 80% of the estimated 10,000 Near Earth Objects (NEOs). • About 1200 are potentially hazardous. • For large asteroids we may get a few years of warning. • Some hazardous asteroids will come close but none will strike the Earth in the next few ye ...
... The Asteroid with Our Name on It • We have found about 80% of the estimated 10,000 Near Earth Objects (NEOs). • About 1200 are potentially hazardous. • For large asteroids we may get a few years of warning. • Some hazardous asteroids will come close but none will strike the Earth in the next few ye ...
Evidence from the asteroid belt for a violent past evolution of
... We use the current orbital structure of large (> 50 km) asteroids in the main asteroid belt to constrain the evolution of the giant planets when they migrated from their primordial orbits to their current ones. Minton & Malhotra (2009) showed that the orbital distribution of large asteroids in the m ...
... We use the current orbital structure of large (> 50 km) asteroids in the main asteroid belt to constrain the evolution of the giant planets when they migrated from their primordial orbits to their current ones. Minton & Malhotra (2009) showed that the orbital distribution of large asteroids in the m ...
Project Pan-STARRS and the Outer Solar System - UCLA
... behind the apparent brightness of a comet. Mantling, in particular, modulates the mass loss rate and total brightness in a profound way but is not quantitatively understood: we don’t know how mantling varies with nucleus size or age. Another is that the comets are diffuse objects and it is difficult ...
... behind the apparent brightness of a comet. Mantling, in particular, modulates the mass loss rate and total brightness in a profound way but is not quantitatively understood: we don’t know how mantling varies with nucleus size or age. Another is that the comets are diffuse objects and it is difficult ...
Section 2 Practice Test
... ____ 14. What is the current theory about the origin of the moon? a. The moon was a large asteroid captured by Earth’s gravity. b. The moon resulted when a large body struck Earth. c. The moon formed at the same time from the same materials. d. The moon spun off from a rapidly spinning Earth. ____ 1 ...
... ____ 14. What is the current theory about the origin of the moon? a. The moon was a large asteroid captured by Earth’s gravity. b. The moon resulted when a large body struck Earth. c. The moon formed at the same time from the same materials. d. The moon spun off from a rapidly spinning Earth. ____ 1 ...
Near-Earth object
A near-Earth object (NEO) is a small Solar System body whose orbit brings it into proximity with Earth. All NEOs have a closest approach to the Sun (perihelion) of less than 1.3 astronomical unit (AU). They include about thirteen thousand near-Earth asteroids (NEAs), more than one hundred near-Earth comets (NECs), and a number of solar-orbiting spacecraft and meteoroids, large enough to be tracked in space before striking the Earth. It is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the planet. NEOs have become of increased interest since the 1980s because of increased awareness of the potential danger some of the asteroids or comets pose to Earth, and active mitigations are being researched.NEAs have orbits that lie partly between 0.983 and 1.3 AU away from the Sun. When an NEA is detected it is submitted to the IAU's Minor Planet Center for cataloging. Some NEAs ' orbits intersect that of Earth's so they pose a collision danger. The United States, European Union, and other nations are currently scanning for NEOs in an effort called Spaceguard.In the United States, NASA has a congressional mandate to catalogue all NEOs that are at least 1 kilometer wide, as the impact of such an object would be catastrophic. As of June 2015, there have been 872 NEAs larger than 1 km discovered, of which 153 are potentially hazardous. It was estimated in 2006 that 20% of the mandated objects have not yet been found. As a result of NEOWISE in 2011, it is estimated that 93% of the NEAs larger than 1 km have been found and that only about 70 remain to be discovered. Our inventory is much less complete for smaller objects, which still have potential for large scale damage.Potentially hazardous objects (PHOs) are currently defined based on parameters that measure the object's potential to make threatening close approaches to the Earth. Mostly objects with an Earth minimum orbit intersection distance (MOID) of 0.05 AU or less and an absolute magnitude (H) of 22.0 or brighter (a rough indicator of large size) are considered PHOs. Objects that cannot approach closer to the Earth (i.e. MOID) than 0.05 AU (7,500,000 km; 4,600,000 mi), or are smaller than about 150 m (500 ft) in diameter (i.e. H = 22.0 with assumed albedo of 13%), are not considered PHOs. The NASA Near Earth Object Catalog also includes the approach distances of asteroids and comets measured in lunar distances, and this usage has become a common unit of measure used by the news media in discussing these objects.Some NEOs are of high interest because they can be physically explored with lower mission velocity even than the Moon, due to their combination of low velocity with respect to Earth (ΔV) and small gravity, so they may present interesting scientific opportunities both for direct geochemical and astronomical investigation, and as potentially economical sources of extraterrestrial materials for human exploitation. This makes them an attractive target for exploration. As of 2012, three near-Earth objects have been visited by spacecraft: 433 Eros, by NASA's Near Earth Asteroid Rendezvous probe, 25143 Itokawa, by the JAXA Hayabusa mission, and 4179 Toutatis, by CNSA's Chang'e 2 spacecraft.