L. Philpott
A5068371292- Astro and Planetary Science
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Nuts composition and effects
- Noncommutative and Quantum Gravity Theories
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Remote Sensing and LiDAR Applications
- Geological and Geochemical Analysis
- Cosmology and Gravitation Theories
- Earthquake Detection and Analysis
- Rangeland Management and Livestock Ecology
- Landslides and related hazards
- Pulsars and Gravitational Waves Research
- Advanced Measurement and Detection Methods
- Cryospheric studies and observations
- Space Exploration and Technology
- Space Satellite Systems and Control
University of British Columbia
2013-2021
Canadian Space Agency
2021
Planetary Science Institute
2020
University of Arizona
2020
Victoria University of Wellington
2015
University of Auckland
2003-2010
Imperial College London
2009-2010
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 the first measurement of planet frequency beyond "snow line," for planet-to-star mass-ratio interval −4.5 < log q −2, corresponding to range ice giants gas giants. find at mean mass ratio = 5 × 10−4 with no discernible deviation from a flat (Öpik's law) distribution in log-projected separation s. The determination is based on sample six planets detected intensive follow-up observations high-magnification (A>200) microlensing events during 2005–2008. sampled host stars have typical...
Abstract We use observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, in orbit around Mercury, to investigate interplanetary coronal mass ejections (ICMEs) near 0.3 AU. MESSENGER is first spacecraft since Helios 1 2 1980s make situ measurements of medium at heliocentric distances < 0.5 As such, it presents a unique opportunity for observing innermost heliosphere. It also allows ICMEs well within AU study their evolution as they expand...
Impolite planet ignores host's partner Many known exoplanets (planets outside our own solar system) are hosted by binary systems that contain two stars. These planets normally circle around both of their Using microlensing data taken with a worldwide network telescopes, Gould et al. found twice the mass Earth circles just one pair The same approach has potential to uncover other similar star and help illuminate some mysteries formation. Science , this issue p. 46
Old minerals expose an ancient field Mercury is the only terrestrial planet other than Earth with active, internally generated magnetic field. Results from MESSENGER spacecraft indicate that almost as old planet. Johnson et al. took advantage of close flybys to extract evidence Certain are able “lock in” signature a at time they crystallize. This remnant magnetization was found in region on believed be 3.8 billion years old. Science , this issue p. 892
Abstract Accurate knowledge of Mercury's magnetospheric magnetic field is required to understand the sources planet's internal field. We present first model confined within a magnetopause shape derived from Magnetometer observations by MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft. The origin approximated dipole magnitude 190 nT R M 3 , where radius, offset northward 479 km along spin axis. External include currents flowing on boundary in cross‐tail current sheet....
We present an advance towards accurately predicting the arrivals of coronal mass ejections (CMEs) at terrestrial planets, including Earth. For first time, we are able to assess a CME prediction model using data over 2/3 solar cycle observations with Heliophysics System Observatory. validate modeling results 1337 CMEs observed Solar Terrestrial Relations Observatory (STEREO) heliospheric imagers (HI) (science data) from 8 years by 5 in situ observing spacecraft. use self-similar expansion for...
We report the discovery of a microlensing exoplanet OGLE-2012-BLG-0563Lb with planet–star mass ratio . Intensive photometric observations high-magnification event allow us to detect clear signal planet. Although no parallax is detected in light curve, we instead succeed at detecting flux from host star high-resolution JHK'-band images obtained by Subaru/AO188 and Infrared Camera Spectrograph instruments, allowing constrain absolute physical parameters planetary system. With help...
The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling spacecraft in orbit about (ii) pebble-sized particles naturally ejected from Bennu's surface sustained orbits. These yield statistically consistent results up degree order 3, with particle-based being significant 9. Comparisons constant-density shape model show that Bennu has heterogeneous deviations can...
We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling northern and southern hemispheres separately, we find that longitudinal ridges previously identified in north extend into south but are obscured there surface material. In south, more numerous large boulders effectively retain materials imply higher average strength at depth to support them. The has fewer evidence boulder...
We present the analysis of gravitational microlensing event OGLE-2013-BLG-0102. The light curve is characterized by a strong short-term anomaly superposed on smoothly varying lensing with moderate magnification $A_{\rm max}\sim 1.5$. It found that was produced binary lens mass ratio between components $q = 0.13$ and caused passage source trajectory over caustic located away from barycenter binary. From effects due to finite size parallactic motion Earth, physical parameters system are...
Abstract Orbital data from the Magnetometer on MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft allow investigation of magnetic fields induced at top Mercury's core by time‐varying magnetospheric fields. We used 15 Mercury years observations magnetopause position as well field inside magnetosphere to establish presence magnitude an annual induction signal. Our results indicate change in internal axial dipole term, g 1 0 , 7.5 9.5 nT. For negligible mantle...
We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to microlensing event OGLE-2011-BLG-0265. Such system is very rare among known planetary systems and thus important for theoretical studies formation evolution. High-cadence temporal coverage signal combined with extended observations throughout allows us accurately model observed light curve. The final solution remains, however, degenerate yielding two possible configurations host star. In case...
OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) is a NASA mission to return sample of asteroid (101955) Bennu. Photometric modeling Bennu's surface key element both site characterization our broader scientific understanding the asteroid. heterogeneous presents substantial variation in reflectance produces scattered dataset that poses challenge photometric modeling. We show resolution shape model with which we calculate angles strongly...
Abstract Mercury's solar wind and interplanetary magnetic field environment is highly dynamic, variations in these external conditions directly control the current systems fields inside planetary magnetosphere. We update our previous static model of by incorporating magnetospheric systems, parameterized as functions heliocentric distance activity. The new, dynamic reproduces location magnetopause system a function systematic pressure encountered during eccentric orbit, well increase...
A measurement by microlensing of the planetary mass function planets with masses ranging from 5M_E to 10M_J and orbital radii 0.5 10 AU was reported recently. strategy for extending range down (1-3)M_E is proposed here. This entails monitoring peaks a few tens events moderately high magnifications 1-2m class telescopes. Planets Earth are found produce deviations ~ 5% light curves durations (0.7-3)hr in magnification 100 if projected separation planet lies annular region (0.85-1.2)r_E....
Abstract The MErcury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited Mercury between March 2011 April 2015, typically passing through the magnetosphere, magnetosheath, interplanetary magnetic field, on each orbit. Using data from Magnetometer, we identify magnetopause crossings for complete orbital mission model average boundary shape. We find that Mercury's is well modeled by both an axisymmetric shape a three‐dimensional containing indentations in cusp...
Mercury's magnetosphere is known to be affected by enhanced ram pressures and magnetic fields inside interplanetary coronal mass ejections (ICMEs). Here we report detailed observations of an ICME compressing dayside the surface. A fast CME launched from Sun on November 29 2013 impacted first MESSENGER, which was orbiting Mercury, 30 later STEREO-A near 1 AU December 1. Following impact, MESSENGER remained in solar wind as spacecraft traveled inwards northwards towards surface until it...
Abstract NASA’s OSIRIS-REx mission to asteroid (101955) Bennu relied on the production of real-time shape models for both spacecraft navigation and scientific analysis. The primary method constructing during early phases was image-based stereophotoclinometry (SPC). SPC were used operational planning, navigation, sample site selection, initial investigations. To this end, detailed analyses quality each model a thorough documentation all sources error vital ensure proper considerations...