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Post Info TOPIC: Datura cluster
Blobrana


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RE: Datura cluster
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Optical spectroscopy from the Gemini telescopes has revealed a relatively uncommon type of asteroid in the main-belt for the first time. The discovery was made by a joint Brazil and US project led by Thais Mothé-Diniz of the Observatório Nacional in Rio de Janeiro and David Nesvorný of the Southwest Research Institute (Boulder, Colorado). The team used both GMOS North and South to obtain optical spectra of asteroids with estimated ages of less than 1 Myr which they then compared to laboratory spectra of meteorites that have fallen to Earth. They found that spectra of asteroids in the newly discovered Datura family have a deep absorption feature near 0.8 microns which classifies them as Q-type asteroids. This spectral feature is produced by silicate material, in particular olivine and pyroxene. Most interestingly, the spectra of Q-type objects are well-matched to the most common type of meteorite found on Earth called an ordinary chondrite (OC).

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-- Edited by Blobrana at 13:47, 2008-09-15

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Blobrana


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Title: Rotation-Resolved Spectroscopy of a Very Young Asteroid, (1270) Datura
Authors: Naruhisa Takato (Subaru telescope)

(1270) Datura is the largest member of a very young asteroid cluster that was thought to be broken-up 0.45 Myr ago. The light-curve and the rotation-resolved reflectance spectra (0.6 um - 1.0 um) were observed in order to find "fresh" surface. Our data show no significant spectral variation along the rotation phase. The depth of the 0.95 um absorption band, which indicates the degree of space weathering, was similar to that of an old S-type asteroid. This suggests that the reflectance spectrum in this wavelength range changes rapidly and saturates the depth of the 0.95 um absorption in less than 0.45 Myr in the main belt environment.

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Blobrana


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Asteroid (1270) Datura
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Discovery of the source of the most common meteorites
When observing with the GEMINI telescopes, two astronomers from Brazil and the United States discovered for the first time asteroids that are similar to “ordinary chondrites”, the most common meteorites found on Earth. Until now, astronomers have failed to identify their asteroidal sources because of the various geologic processes that occur after the meteorites are ejected from their asteroidal parent body. This discovery is being published this week in Astronomy & Astrophysics.

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Blobrana


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Title: New Candidates for Recent Asteroid Breakups
Authors: D. Nesvorný and D. Vokrouhlický

Asteroids in our solar system formed in a dynamically quiescent disk, but their orbits became gravitationally stirred enough by Jupiter to lead to high-speed collisions. As a result, several dozen large asteroids have been disrupted by impacts over the past several gigayears and have produced groups of fragments called asteroid families. Here we report three new candidates for asteroid families that were formed by collisions occurring in the last 1 Myr. According to our modelling of the past orbital histories of known cluster members, we estimate that the Emilkowalski, 1992 YC2, and Lucascavin clusters are 220±30, 50 - 250, and 300 - 800 kyr old, respectively. Together with the previously identified Datura cluster, estimated to be 450±50 kyr old, they are the most recent asteroid breakups ever discovered in the main belt. Astronomical observations of identified family members can be used to better understand impact physics, asteroid composition, and surface-aging processes. Discovered breakups may also be important sources of interplanetary dust.

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David Vokrouhlicky is currently investigating possible new members,  (89309) 2001VN36 & 2001 WY35,  that were formed within the past million years.

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Blobrana


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Title: The Breakup of a Main-Belt Asteroid 450 Thousand Years Ago
Authors: David Nesvorny, David Vokrouhlicky, William F. Bottke

Collisions in the asteroid belt frequently lead to catastrophic breakups, where more than half of the target's mass is ejected into space. Several dozen large asteroids have been disrupted by impacts over the past several billion years. These impact events have produced groups of fragments with similar orbits called asteroid families. Here we report the discovery of a very young asteroid family around the object 1270 Datura. Our work takes advantage of a method for identification of recent breakups in the asteroid belt using catalogues of osculating (i.e., instantaneous) asteroid orbits. The very young families show up in these catalogues as clusters in a five-dimensional space of osculating orbital elements.

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