C. W. Hergenrother
A5068595115- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Gamma-ray bursts and supernovae
- Space exploration and regulation
- Space Exploration and Technology
- Atmospheric Ozone and Climate
- Space Satellite Systems and Control
- Astronomical Observations and Instrumentation
- Spacecraft and Cryogenic Technologies
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Spacecraft Design and Technology
- Distributed systems and fault tolerance
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- SAS software applications and methods
- Geological and Geochemical Analysis
- Space Science and Extraterrestrial Life
- Photocathodes and Microchannel Plates
Research Corporation Technologies (United States)
2024-2025
University of Arizona
2014-2024
Planetary Science Institute
2006-2022
Lunar and Planetary Institute
2018
Center for Astrophysics Harvard & Smithsonian
2006-2007
Harvard University Press
2006
European Southern Observatory
2005
University of Maryland, College Park
2005
University of Liège
2005
Pomona College
2005
Abstract During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, rotation state. Discovery of a dusty natural satellite, or unexpected characteristics would have had consequences for the mission’s safety observation strategy. Here we show that observations during this period were highly sensitive satellites (sub-meter...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part a continuing monitoring campaign at the Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is largest homogeneously reduced sample SNe date, nearly doubling number well-observed, nearby with published multicolor CCD light curves. large U-band unique addition, important connections high redshift. decline rate SN curves...
Abstract We review the results of an extensive campaign to determine physical, geological, and dynamical properties asteroid (101955) Bennu. This investigation provides information on orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, environmental combine these data with cosmochemical models develop a hypothetical timeline for Bennu's formation evolution. infer that Bennu is ancient object has witnessed over 4.5 Gyr solar system history. Its...
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances particle ejection from the surface (101955) Bennu, demonstrating it is an active asteroid. The events were imaged by OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For three largest observed events, we estimated ejected velocities sizes, event times, source regions, energies. also determined trajectories photometric properties...
Carbonaceous asteroids, such as (101955) Bennu, preserve material from the early Solar System, including volatile compounds and organic molecules. We report spacecraft imaging spectral data collected during after retrieval of a sample Bennu’s surface. The sampling event mobilized rocks dust into debris plume, excavating 9-meter-long elliptical crater. This exposed is darker, spectrally redder, more abundant in fine particulates than original bulk density displaced subsurface was 500 to 700...
We present RIz photometry of four consecutive transits the newly discovered exoplanet XO-1b. improve upon estimates transit parameters, finding planetary radius to be R_P = 1.184 +0.028/-0.018 R_Jupiter and stellar R_S 0.928 +0.018/-0.013 R_Sun, assuming a mass M_S 1.00 +/- 0.03 M_Sun. The uncertainties in radii are dominated by uncertainty mass. These increase factor 2-3 if more conservative 0.10 M_Sun is assumed for Our estimate smaller than that reported McCullough et al. (2006) yields...
On 4 July 2005, many observatories around the world and in space observed collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there new material after impact compositionally different from seen before impact; (ii) ratio dust mass to gas ejecta much larger than (iii) activity did not last more a few days, by 9 comet's behavior indistinguishable pre-impact behavior; (iv) were interesting...
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their texture. Space weathering Bennu materials does not simply progress from red (or vice versa). Instead, freshly exposed, redder surfaces initially...
When the OSIRIS-REx spacecraft pressed its sample collection mechanism into surface of Bennu, it provided a direct test poorly understood near-subsurface physical properties rubble-pile asteroids, which consist rock fragments at rest in microgravity. Here, we find that forces measured by are best modeled as granular bed with near-zero cohesion is half dense bulk asteroid. The low gravity small asteroid such Bennu effectively weakens near subsurface not compressing upper layers, thereby...
Abstract We analyze the trajectories of 313 particles seen in near‐Bennu environment between December 2018 and September 2019. Of these, 65% follow suborbital trajectories, 20% undergo more than one orbital revolution around asteroid, 15% directly escape on hyperbolic trajectories. The median lifetime these is ∼6 hr. are sensitive to Bennu's gravitational field, which allows us reliably estimate spherical harmonic coefficients through degree 8 resolve nonuniform mass distribution 3....
Many boulders on (101955) Bennu, a near-Earth rubble pile asteroid, show signs of in situ disaggregation and exfoliation, indicating that thermal fatigue plays an important role its landscape evolution. Observations particle ejections from surface also it to be active though the driving mechanism these events is yet determined. Exfoliation has been shown mobilize disaggregated particles terrestrial environments, suggesting may capable ejecting material Bennu's surface. We investigate nature...
Abstract On 2022 September 26, the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, satellite of binary near-Earth asteroid (65803) Didymos. This demonstrated efficacy a kinetic impactor for planetary defense by changing orbital period Dimorphos 33 minutes. Measuring change relied heavily on coordinated campaign lightcurve photometry designed to detect mutual events (occultations and eclipses) as direct probe satellite’s period. A total 28 telescopes contributed 224...
We present optical and near-infrared photometry spectroscopy of the type Ia SN 1998bu in Leo I Group galaxy M96 (NGC 3368). The data set consists 356 photometric measurements 29 spectra between UT 1998 May 11 July 15. well-sampled light curve indicates supernova reached maximum B on 19.3 (JD 2450952.8 +/- 0.8) with = 12.22 0.03 V 11.88 0.02. Application a revised version Multicolor Light Curve Shape (MLCS) method yields an extinction toward A_V 0.94 0.15 mag, was average luminosity compared...