
William V. BoyntonUniversity of Arizona | UA · Department of Planetary Sciences
William V. Boynton
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Publications
Publications (816)
The Thermal Evolved Gas Analyzer (TEGA) analysis of surface and icy subsurface Phoenix landing site soils consisted of low (300–700°C) and high (>700°C) temperature CO2 evolutions that were attributed to organic carbon (83–1,484 μgC/g) and Ca‐rich carbonate (1.1–2.6 wt.%). Total carbon abundances ranged from 1,143 to 4,905 µgC/g, which is the highe...
The REgolith X-ray Imaging Spectrometer (REXIS) instrument on board NASA’s OSIRIS-REx mission to the asteroid Bennu is a Class-D student collaboration experiment designed to detect fluoresced X-rays from the asteroid’s surface to measure elemental abundances. In July and November 2019 REXIS collected ∼615 hours of integrated exposure time of Bennu’...
The REgolith X-ray Imaging Spectrometer (REXIS) instrument on board NASA's OSIRIS-REx mission to the asteroid Bennu is a Class-D student collaboration experiment designed to detect fluoresced X-rays from the asteroid's surface to measure elemental abundances. In July and November 2019 REXIS collected ~615 hours of integrated exposure time of Bennu'...
This paper reviews improved calibration methods for the Lunar Reconnaissance Orbiter Lunar Exploration Neutron Detector. We cross calibrated the set of LEND observations and models of its detectors physical geometry and composition against the McKinney Apollo 17 era measured neutron flux, Lunar Prospector Neutron Spectrometer epithermal neutron obs...
We manually mapped particles ranging in longest axis from 0.3 cm to 95 m on (101955) Bennu for the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) asteroid sample return mission. This enabled the mission to identify candidate sample collection sites and shed light on the processes that have sha...
Soft γ-ray repeaters exhibit bursting emission in hard X-rays and soft γ-rays. During the active phase, they emit random short (milliseconds to several seconds long), hard-X-ray bursts, with peak luminosities¹ of 10³⁶ to 10⁴³ erg per second. Occasionally, a giant flare with an energy of around 10⁴⁴ to 10⁴⁶ erg is emitted². These phenomena are thoug...
Magnetars are young, highly magnetized neutron stars that produce extremely rare giant flares of gamma-rays, the most luminous astrophysical phenomena in our Galaxy. The detection of these flares from outside the Local Group of galaxies has been predicted, with just two candidates so far. Here we report on the extremely bright gamma-ray flare GRB 2...
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The OSIRIS-REx Laser Altimeter (OLA) is a scanning lidar instrument with a high measurement rate of 10 kHz and a dexterous two-axis mirror. OLA is optimized for proximity operations (< 7 km range) around a small asteroid. The high repetition rate and scanning capability of the instrument give OLA the ability to rapidly obtain high-density topograph...
This paper outlines and solves the problem of imaging asteroid (101955) Bennu in the presence of spacecraft state perturbation during OSIRIS-REx's approach trajectory. The problem is that the area a mosaic must cover changes size as the spacecraft state is perturbed. We developed and applied a method for determining how much to over-image the the a...
NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth¹. Bennu is a low-albedo B-type asteroid² that...
The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission, Earth-based radar imaging gave an overview...
Early spectral data from the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission reveal evidence for abundant hydrated minerals on the surface of near-Earth asteroid (101955) Bennu in the form of a near-infrared absorption near 2.7 µm and thermal infrared spectral features that are most sim...
The Dynamic Albedo of Neutrons instrument (DAN) onboard the Mars Science Laboratory (MSL) uses ³ He proportional counters to detect neutrons escaping the martian surface. This neutron leakage flux can be used to estimate the amount of hydrogen in the shallow martian regolith. During sols 753 through 1292 of the MSL mission, the rover traversed from...
We examine a sample of 2301 gamma-ray bursts, detected by Konus-Wind in the triggered mode between 1994 and 2017 and localized by the interplanetary network (IPN), for evidence of gravitational lensing. We utilize all the available gamma-ray burst (GRB) data: Time histories, localizations, and energy spectra. We employ common IPN techniques to find...
The OSIRIS-REx Asteroid Sample Return Mission is the third mission in National Aeronautics and Space Administration (NASA)'s New Frontiers Program and is the first U.S. mission to return samples from an asteroid to Earth. The most important decision ahead of the OSIRIS-REx team is the selection of a prime sample-site on the surface of asteroid (101...
The OSIRIS-REx Asteroid Sample Return Mission is the third mission in NASA's New Frontiers Program and is the first U.S. mission to return samples from an asteroid to Earth. The most important decision ahead of the OSIRIS-REx team is the selection of a prime sample-site on the surface of asteroid (101955) Bennu. Mission success hinges on identifyin...
We analyzed high-angular rate streaks first recorded by OSIRIS-REx's MapCam during a 2017 search for Earth Trojan asteroids. We interpret them as water-ice particles that translated across the imager's field of view, originating from the spacecraft itself. Their translation velocities approximated 0.1–1 m/s based on reasonable conclusions about the...
The Mars Science Laboratory Dynamic Albedo of Neutrons (DAN) experiment measures the martian neutron leakage flux in order to estimate the amount of water equivalent hydrogen present in the shallow regolith. When DAN is operating in passive mode, it is sensitive to neutrons produced through the interactions of galactic cosmic rays (GCR) with the re...
Neutron flux measurements by the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) enable quantifying hydrogen-bearing volatiles in the lunar surface from orbit. Accurately determining hydrogen abundance requires discriminating between the instrument background detection rate and the population of lunar-sourced neu...
The Canadian Space Agency (CSA) has contributed to the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) spacecraft the OSIRIS-REx Laser Altimeter (OLA). The OSIRIS-REx mission will sample asteroid 101955 Bennu, the first B-type asteroid to be visited by a spacecraft. Bennu is thought to be primitive, c...
Analysis of Lunar Exploration Neutron Detector (LEND) neutron count rates for a large set of mid-latitude craters provides evidence for lower hydrogen content in the crater interiors compared to typical highland values. Epithermal neutron count rates for crater interiors measured by the LEND Sensor for Epithermal Neutrons (SETN) were compared to cr...
The Mars Science Laboratory (Curiosity rover) Dynamic Albedo of Neutrons (DAN) experiment detects neutrons for the purpose of searching for hydrogen in the shallow subsurface of Mars. DAN has two modes of operation, active and passive. In passive mode, the instrument detects neutrons produced by Galactic Cosmic Ray interactions in the atmosphere an...
InterPlanetary Network (IPN) data are presented for the gamma-ray bursts in the second Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 462 bursts in that catalog between 2010 July 12 and 2012 July 11, 428, or 93%, were observed by at least 1 other instrument in the 9-spacecraft IPN. Of the 428, the localizations of 165 could be improved by tria...
The OSIRIS-REx spacecraft, launched in September 2016, will rendezvous with asteroid 101955 Bennu in mid 2018. As part of a suite of instruments on the OSIRIS-REx spacecraft, the OSIRIS-REx Laser Altim- eter (OLA) is the world’s first scanning laser range- finder (or lidar) to fly on a planetary mission.
In May of 2011, NASA selected the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission as the third mission in the New Frontiers program. The other two New Frontiers missions are New Horizons, which explored Pluto during a flyby in July 2015 and is on its way for a fly...
In May of 2011, NASA selected the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission as the third mission in the New Frontiers program. The other two New Frontiers missions are New Horizons, which explored Pluto during a flyby in July 2015 and is on its way for a fly...
To evaluate the feasibility of measuring differences in bulk composition among carbonaceous meteorite parent bodies from an asteroid or comet orbiter, we present the results of a performance simulation of an orbital gamma-ray spectroscopy ("GRS") experiment in a Dawn-like orbit around spherical model asteroids with a range of carbonaceous compositi...
To evaluate the feasibility of measuring differences in bulk composition among carbonaceous meteorite parent bodies from an asteroid or comet orbiter, we present the results of a performance simulation of an orbital gamma-ray spectroscopy ("GRS") experiment in a Dawn-like orbit around spherical model asteroids with a range of carbonaceous compositi...
We have performed a blind search for a gamma-ray transient of arbitrary duration and energy spectrum around the time of the LIGO gravitational-wave event GW150914 with the six-spacecraft interplanetary network (IPN). Four gamma-ray bursts were detected between 30 hr prior to the event and 6.1 hr after it, but none could convincingly be associated w...
Results of physical calibrations of the LEND neutron telescope operating on board the NASA’s LRO lunar satellite since June 2009 are described. The main goal of the LEND telescope is to measure the epithermal neutron flux in polar areas of the lunar surface with a high (~10 km) resolution with the aim of determining the hydrogen distribution in the...
We present a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top ∼1 meter layer of lunar regolith. Polar maps of the Moon's inferred hydrogen abundance are presented...
The Dynamic Albedo of Neutron (DAN) instrument on board the Mars Science Laboratory Curiosity rover acquired a series of measurements as part of an observational campaign of the Kimberley area in Gale crater. These observations were planned to assess the variability of bulk hydrogen and neutron-absorbing elements, characterized as chlorine-equivale...
Lunar neutron flux data measured by the Lunar Exploration Neutron Detector (LEND) onboard NASA’s Lunar Reconnaissance Orbiter (LRO) were analyzed for the period 2009-2014. We have re-evaluated the instrument’s collimation capability and re-estimated the neutron counting rate measured in the Field of View (FOV) of the LEND collimated detectors, and...
The detection of a gamma-ray burst (GRB) in the solar neighborhood would have
very important implications for GRB phenomenology. The leading theories for
cosmological GRBs would not be able to explain such events. The final bursts of
evaporating Primordial Black Holes (PBHs), however, would be a natural
explanation for local GRBs. We present a nove...
The Dynamic Albedo of Neutrons (DAN) experiment on the Mars Science Laboratory (MSL) rover Curiosity is designed to detect neutrons to determine hydrogen abundance within the subsurface of Mars (Mitrofanov, I.G. et al. [2012]. Space Sci. Rev. 170, 559-582. http://dx.doi.org/10.1007/s11214-012-9924-y; Litvak, M.L. et al. [2008]. Astrobiology 8, 605-...
In September of 2016, the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith EXplorer) spacecraft will depart for asteroid (101955) Bennu, and when it does, humanity will turn an important corner in the exploration of the Solar System. After arriving at the asteroid in the Fall of 2018, it will undertake a pro...
The Lunar Exploration Neutron Detector (LEND), on the polar-orbiting Lunar Reconnaissance Orbiter (LRO) spacecraft, has detected suppression in the Moon’s naturally-occurring epithermal neutron leakage flux that is consistent with the presence of diurnally varying quantities of hydrogen in the regolith near the equator. Peak hydrogen concentration...
Searching for water in the soil of Gale Crater is one of the primary tasks for the NASA Mars Science Laboratory rover named Curiosity. The primary task of the Dynamic Albedo of Neutrons (DAN) experiment on board the rover is to investigate and qualitatively characterize the presence of water along the rover’s traverse across Gale Crater. The water...
C, H, O, and S can be measured by a Mars Odyssey-like orbital gamma-ray spectrometer in a Dawn-like orbit around a carbonaceous asteroid within 4.5 months.
Epithermal neutron observations from the LRO's LEND detector is used to derive evidence of an active diurnal hydration process in the Moon's high latitudes.
The evidence for sulfate-bearing strata, across Late-Noachian to Amazonian eons, suggests a central role for sulfates in acidity and salinity of martian paleo-fluids and the planet's habitability. However, details remain unclear owing to shallow sampling and the limited ability of visible/near-infrared spectroscopy to distinguish among some sulfate...
Pole-facing slopes maintain enhanced concentrations of hydrogen in the Moon’s southern latitudes.•Pole-facing slopes are being hydrated in a continuum of spatial scales perhaps approaching the level of meter scales.•Pole-facing slopes may act as local cool-traps for hydrogen accumulation outside of permanent shadow.•The poleward hydration of pole-f...
The presence of hydrated phases in the soil and near-surface bedrock of Gale Crater is thought to be direct evidence for water-rock interaction in the crater in the ancient past. Layered sediments over the Gale Crater floor are thought to have formed in past epochs due to sediment transport, accumulation, and cementation through interaction with fl...
Data gathered with the Dynamic Albedo of Neutrons (DAN) instrument onboard Curiosity rover were analyzed for variations in subsurface neutron flux and tested for possible correlation with local geological context. A special DAN observation campaign was executed in which 18 adjacent DAN active measurements were acquired every 0.75-1.0 m to search fo...
We present optical photometry and spectroscopy of the broad-lined Type Ic supernova (SN Ic-BL) PTF10qts, which was discovered
as part of the Palomar Transient Factory. The SN was located in a dwarf galaxy of magnitude r = 21.1 at a redshift z = 0.0907. We find that the R-band light curve is a poor proxy for bolometric data and use photometric and s...
Mars's Gale Crater is located near the equator and is 155 km in diameter. The crater is estimated to be 3.5 3.8 billion years old. It originates from a large asteroid strike in the Noachian period. The primary scientific objective of the NASA Curiosity rover is to find out whether the early Mars environment was favorable for the origin and sustenan...
Results of LEND, LOLA, and Diviner multi-instrument data analysis to find minimal depth and low limit of hydrogen concentration in regolith will be presented.
We demonstrate the results of applied deconvolution to reconstruct fine structures of PSRs (permanent shadowed regions) in Cabeus and Shoemaker.
We illustrate evidence that a pervasive hydration of the Moon's poleward-facing slopes reaching to -60° latitude.
The data reduction procedures that reduce the LEND raw elliptical orbit CSETN neutron data into corrected higher-level derived data products are presented.
The LRO was launched June 18, 2009 during an historic spaceage era of minimum solar activity and maximum GCR flux that coincided with the operation of LEND.
The portion of lunar-sourced neutrons detected by LEND in collimation can be deduced from altitude variation. It is needed to estimate H concentrations in PSRs.
The data analysis of the DAN active measurements onboard the Curiosity rover is presented for 154 individual points along 1900 meters of the rover traverse.
We introduce Miniature X-ray Optics to bring highly successful Wolter-I X-ray optics to planetary science within affordable mass, power, and cost constraints.
DAN data acquired in and around Yellowknife Bay are modeled using full elemental geochemistries from APXS and SAM.
Water can be found at the Moon’s dawn terminator at the peak of a daily cycle of dehydration and rehydration, equivalent to a frost 0.2 mm thick.
The comparison of orbital and surface studies of subsurface water distribution at equatorial latitudes of Mars based on neutron spectrometry measurements.
Gamma Ray Bursts (GRBs) are characterized by ultra-relativistic outflows,
while supernovae are generally characterized by non-relativistic ejecta. GRB
afterglows decelerate rapidly usually within days, because their low-mass
ejecta rapidly sweep up a comparatively larger mass of circumstellar material.
However supernovae, with heavy ejecta, can be...
The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both i...
GRB 110918A is the brightest long gamma-ray burst (GRB) detected by Konus-WIND during its almost 19 yr of continuous observations and the most luminous GRB ever observed since the beginning of the cosmological era in 1997. We report on the final Interplanetary Network localization of this event and its detailed multiwavelength study with a number o...
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an
approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering
is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absen...
We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion
years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the
crater rim. Cosmic-ray–produced 3He, 21Ne, and 36Ar yield concordant surface exposure ages of 78...
[1] The Dynamic Albedo of Neutrons (DAN) instrument on board Mars Science Laboratory has been operating successfully since the landing and has been making measurements regularly along Curiosity's traverse at the surface. DAN measures thermal (E < 0.4 eV) and epithermal neutrons (0.4 eV < E < ~1 keV) whil