Near-infrared (2-4 Micron) Spectroscopy of Near-earth Asteroids PDF Download
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Author: Nathanael Richard Wigton
Publisher:
ISBN:
Category :
Languages : en
Pages : 61
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Book Description
Near-Earth asteroids (NEAs) are not expected to have H2O [water] ice on their surfaces because a) most accreted dry and therefore never contained H2O, and b) their relatively high surface temperatures should drive rapid H2O ice sublimation. However, OH/H2O has been detected on other anhydrous inner solar system objects, including the Moon and Vesta. Possible sources for OH/H2O in the inner Solar System might include production via solar wind interactions, carbonaceous chondrite or cometary impact delivery, or native OH/H2O molecules bound to phyllosilicates. As these processes are active in near-Earth space, detectable levels of OH/H2O might also be present on NEAs. OH/H2O can be detected by its absorption feature at wavelengths near 3 microns using near-infrared (2 - 4 microns) spectroscopy from ground-based infrared telescopes. Analysis of the shape of the 3-micron feature, coupled with the observed NEA orbital parameters and albedos, can help distinguish between the possible sources of OH/H2O. I used the SpeX instrument on NASA's Infrared Telescope Facility (IRTF) to measure spectra in from ~2 to 4 [mu]m[microns]. The study presented here uses 13 observations for 8 NEAs: (443) Eros (two observations), (1036) Ganymed (four observations), (3122) Florence, (54789) 2001 MZ7, (96590) 1998 XB, (285944) 2001 RZ11, (214088) 2004 JN13, (357439) 2004 BL86. The objects are split into two spectral groups based on band depth: No feature or shallow feature (
Author: Nathanael Richard Wigton
Publisher:
ISBN:
Category :
Languages : en
Pages : 61
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Book Description
Near-Earth asteroids (NEAs) are not expected to have H2O [water] ice on their surfaces because a) most accreted dry and therefore never contained H2O, and b) their relatively high surface temperatures should drive rapid H2O ice sublimation. However, OH/H2O has been detected on other anhydrous inner solar system objects, including the Moon and Vesta. Possible sources for OH/H2O in the inner Solar System might include production via solar wind interactions, carbonaceous chondrite or cometary impact delivery, or native OH/H2O molecules bound to phyllosilicates. As these processes are active in near-Earth space, detectable levels of OH/H2O might also be present on NEAs. OH/H2O can be detected by its absorption feature at wavelengths near 3 microns using near-infrared (2 - 4 microns) spectroscopy from ground-based infrared telescopes. Analysis of the shape of the 3-micron feature, coupled with the observed NEA orbital parameters and albedos, can help distinguish between the possible sources of OH/H2O. I used the SpeX instrument on NASA's Infrared Telescope Facility (IRTF) to measure spectra in from ~2 to 4 [mu]m[microns]. The study presented here uses 13 observations for 8 NEAs: (443) Eros (two observations), (1036) Ganymed (four observations), (3122) Florence, (54789) 2001 MZ7, (96590) 1998 XB, (285944) 2001 RZ11, (214088) 2004 JN13, (357439) 2004 BL86. The objects are split into two spectral groups based on band depth: No feature or shallow feature (
Author: Skylar S. Larsen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
The near-infrared spectra of four near-Earth asteroids, 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan, were analyzed for traces of surface water. NEAs are widely thought to be the source of water and organics delivered to early Earth. Additionally, some NEAs are considered potentially hazardous objects (PHOs), and they could make threateningly close approaches to our planet. The Infrared Telescope Facility (IRTF), located at Mauna Kea, Hawaii, was used to measure long wavelength cross-dispersed (LXD) spectra of these four asteroids with SpeX mode. The measured spectra wavelength ranged from 1.67-4.2 [mu]m, which includes the 3-[mu]m feature attributed to water/hydroxyl. The 3[mu]m spectral feature was found on Florence, but not on 2004 BL86; meanwhile, the Ganymed and Magellan results were inconclusive. Discovering water on a celestial body such as Florence, an S-type asteroid, is highly unusual and warrants further study.
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309493986
Category : Science
Languages : en
Pages : 75
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Book Description
Near Earth objects (NEOs) have the potential to cause significant damage on Earth. In December 2018, an asteroid exploded in the upper atmosphere over the Bering Sea (western Pacific Ocean) with the explosive force of nearly 10 times that of the Hiroshima bomb. While the frequency of NEO impacts rises in inverse proportion to their sizes, it is still critical to monitor NEO activity in order to prepare defenses for these rare but dangerous threats. Currently, NASA funds a network of ground-based telescopes and a single, soon-to-expire space-based asset to detect and track large asteroids that could cause major damage if they struck Earth. This asset is crucial to NEO tracking as thermal-infrared detection and tracking of asteroids can only be accomplished on a space-based platform. Finding Hazardous Asteroids Using Infrared and Visible Wavelength Telescopes explores the advantages and disadvantages of infrared (IR) technology and visible wavelength observations of NEOs. This report reviews the techniques that could be used to obtain NEO sizes from an infrared spectrum and delineate the associated errors in determining the size. It also evaluates the strengths and weaknesses of these techniques and recommends the most valid techniques that give reproducible results with quantifiable errors.
Author: Ronald Adrey Fevig
Publisher:
ISBN:
Category :
Languages : en
Pages : 288
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Book Description
Results of visible to near-infrared spectrophotometric observations of 55 near-Earth asteroids (NEAs) are reported. The observing techniques, instrumentation, and method of data analysis are described. A new asteroid classification method that directly compares these NEA spectra with spectral features of meteorites is presented. Two major siliceous groups (having discernible"1-micron"absorptions) result from this method, OC-likes which match the spectra of ordinary chondrites and S-types. The dataset shows a preponderance of spectra consistent with ordinary chondrites (23 NEAs), as well as S-types (19), 2 with spectra consistent with black ordinary chondrites, 2 R-types, and 9 that show no 1-micron absorption. The spectral characteristics of the siliceous S-type and OC-like asteroids blend together, providing evidence that S-type asteroids are simply ordinary chondrites whose surface has been modified by weathering. This helps resolve the long standing question of the lack of main belt asteroids having spectra matching ordinary chondrite meteorites. Main belt asteroids have on average much older surfaces while NEAs that exhibit OC-like spectra have younger surfaces. It was found that fresh objects having spectra consistent with ordinary chondrites (1) occupy mostly highly eccentric Apollo orbits which encounter a strong collisional environment in the asteroid main-belt, (2) may have been recently injected into high eccentricity orbits, or (3) have suffered tidal disruption. S-type NEAs reside primarily in orbits that do not cross the asteroid main-belt. This orbit dependent trend is verified by using the larger NEA dataset of Binzel et al. (2004a). Nine NEAs from this survey exhibiting no 1-micron absorption can be associated with extinct comets, iron meteorites or enstatite meteorites. It is shown that most of these NEAs must be extinct comets, implying a considerably larger fraction of comets among the NEA population than previously thought. A correlation of these objects with low inclination orbits is found. This study finds that the NEA population is divided roughly as follows: 4̃0% fresh ordinary chondrites, 3̃5% S-types, 2̃0% extinct comet candidates, and 5̃% in minor classes. This work may guide NEA mitigation planning should such an emergency arise.
Author: Sean Ernest Marshall
Publisher:
ISBN:
Category :
Languages : en
Pages : 496
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Book Description
Chapter 1: Near-Earth asteroids are some of Earth's closest neighbors in space. Thousands are known, with dozens of new ones being discovered every week. Yet the physical characterization of near-Earth asteroids lags well behind discovery. Studying some asteroids in detail helps to reveal the properties of the overall population. This work focuses on the detailed characterization of a few specific near-Earth asteroids with high-quality data sets, particularly radar observations that can be used to determine their shapes and rotation states. Incorporating multiple types of observational data enables much better characterization than could be done with any single data set. Chapter 2: For (162421) 2000 ET70, incorporating lightcurves that had not been used for the modeling of Naidu et al. (2013) allows a better determination of its dimensions and rotation state. Incorporating infrared spectra further refines ET70's rotation state, since thermal modeling shows that some pole directions that provide good fits to the radar and lightcurve data are not compatible with the infrared observations. Thermal modeling also indicates that ET70's surface is heterogeneous, since no thermal model with uniform surface properties could provide an adequate fit to all of the infrared spectra. Chapter 3: (85989) 1999 JD6 was observed to have a large amplitude in visible and infrared lightcurves, suggesting that it is a highly elongated body. Radar images obtained during JD6's close approach in 2015 confirm this, revealing a contact binary with a maximum breadth of 3.0 km. Due to fortuitous observing geometry during some of the radar observations, its rotation state can be determined to great accuracy. The direction of JD6's rotation axis is known more accurately than that of any other asteroid for which only Earth-based observations are available. Chapter 4: One promising way to speed up part of the asteroid shape modeling process is by using Bayesian optimization to test pole directions autonomously. This requires less computational time and less human oversight than a traditional grid search.
Author: Janice L. Bishop
Publisher: Cambridge University Press
ISBN: 110718620X
Category : Language Arts & Disciplines
Languages : en
Pages : 655
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Book Description
Comprehensive overview of the spectroscopic, mineralogical, and geochemical techniques used in planetary remote sensing.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309060834
Category : Science
Languages : en
Pages : 45
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Book Description
Comets and asteroids are in some sense the fossils of the solar system. They have avoided most of the drastic physical processing that shaped the planets and thus represent more closely the properties of the primordial solar nebula. What processing has taken place is itself of interest in decoding the history of our solar neighborhood. Near-Earth objects are also of interest because one or more large ones have been blamed for the rare but devastating events that caused mass extinctions of species on our planet, as attested by recent excitement over the impending passage of asteroid 1997 XF11. The comets and asteroids whose orbits bring them close to Earth are clearly the most accessible to detailed investigation, both from the ground and from spacecraft. When nature kindly delivers the occasional asteroid to the surface of Earth as a meteorite, we can scrutinize it closely in the laboratory; a great deal of information about primordial chemical composition and primitive processes has been gleaned from such objects. This report reviews the current state of research on near-Earth objects and considers future directions. Attention is paid to the important interplay between ground-based investigations and spaceborne observation or sample collection and return. This is particularly timely since one U.S. spacecraft is already on its way to rendezvous with a near-Earth object, and two others plus a Japanese mission are being readied for launch. In addition to scientific issues, the report considers technologies that would enable further advances in capability and points out the possibilities for including near-Earth objects in any future expansion of human exploration beyond low Earth orbit.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721298303
Category :
Languages : en
Pages : 40
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Book Description
Optical/near-infrared studies of asteroids are based on reflected sunlight and surface albedo variations create broad spectral features, suggestive of families of materials. There is a significant literature on these features, but there is very little work in the thermal infrared that directly probes the materials emitting on the surfaces of asteroids. We have searched for and extracted 534 thermal spectra of 245 asteroids from the original Dutch (Groningen) archive of spectra observed by the IRAS Low Resolution Spectrometer (LRS). We find that, in general, the observed shapes of the spectral continua are inconsistent with that predicted by the standard thermal model used by IRAS. Thermal models such as proposed by Harris (1998) and Harris et al.(1998) for the near-earth asteroids with the "beaming parameter" in the range of 1.0 to 1.2 best represent the observed spectral shapes. This implies that the IRAS Minor Planet Survey (IMPS, Tedesco, 1992) and the Supplementary IMPS (SIMPS, Tedesco, et al., 2002) derived asteroid diameters are systematically underestimated, and the albedos are overestimated. We have tentatively identified several spectral features that appear to be diagnostic of at least families of materials. The variation of spectral features with taxonomic class hints that thermal infrared spectra can be a valuable tool for taxonomic classification of asteroids. Cohen, Martin and Walker, Russell G. Goddard Space Flight Center VRISV-1140-001-Final-Report
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 376
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Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: Patrick Michel
Publisher: University of Arizona Press
ISBN: 0816532133
Category : Science
Languages : en
Pages : 946
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Book Description
"More than forty chapters detail our current astronomical, compositional, geological, and geophysical knowledge of asteroids, as well as their unique physical processes and interrelationships with comets and meteorites"--Provided by publisher.
