A5046753683- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Space Exploration and Technology
- Spacecraft and Cryogenic Technologies
- Spacecraft Design and Technology
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Space Satellite Systems and Control
- Geological and Geochemical Analysis
- Geology and Paleoclimatology Research
- Distributed and Parallel Computing Systems
- Advanced ceramic materials synthesis
- Radio Astronomy Observations and Technology
- Atmospheric Ozone and Climate
- Space Science and Extraterrestrial Life
- Methane Hydrates and Related Phenomena
Northern Arizona University
2015-2024
Lowell Observatory
2016-2023
South African Radio Astronomy Observatory
2015-2021
Jet Propulsion Laboratory
2015-2019
University of the Western Cape
2015-2017
University of Colorado Boulder
2017
Carnegie Institution for Science
2017
The University of Tokyo
2015
Fundació Observatori Esteve Duran
2011
University of Hawaii System
2011
We report new Spitzer 24 μm photometry of 76 main-sequence A-type stars. combine these results with previously reported data and 25 from the Infrared Space Observatory Astronomy Satellite. The result is a sample 266 stars mass close to 2.5 M☉, all detected at least ~7 σ level relative their photospheric emission. culled ages for entire literature and/or estimated them using H-R diagram isochrones; they range 5 850 Myr. identified excess thermal emission an internally derived K - (or 25)...
We observed 69 A3-F8 main-sequence binary star systems using the Multiband Imaging Photometer for Spitzer on board Space Telescope. find emission significantly in excess of predicted photospheric flux levels 9 % and 40 these at 24 70 μm, respectively. Twenty-two total have emission, including four that show both wavelengths. A very large fraction (nearly 60%) with small (<3 AU) separations thermal emission. interpret infrared excesses as from dust produced by collisions planetesimal belts....
[Condensed] We search 0.02 deg^2 for trans-Neptunian objects (TNOs) with m<=29.2 (diameter ~15 km) using the ACS on HST. Three new are discovered, roughly 25 times fewer than expected from extrapolation of differential sky density Sigma(m) brighter objects. The and other recent TNO surveys show departures a power law size distribution. Division sample into ``classical Kuiper belt'' (CKB) ``Excited'' samples reveals that differs two populations at 96% confidence. A double adequately fits...
Giant planets in circumstellar disks can migrate inward from their initial (formation) positions. Radial migration is caused by torques between the planet and disk, outward spinning star, due to Roche lobe overflow consequent mass loss planet. We present self-consistent numerical considerations of problem migrating giant planets. Summing on for various physical parameters, we find that Jupiter-mass stably arrive survive at small heliocentric distances, thus reproducing observed properties...
We report 24 and/or 70 μm measurements of ~160 A-type main-sequence stars using the Multiband Imaging Photometer for Spitzer (MIPS). Their ages range from 5 to 850 Myr, based on estimates literature (cluster or moving group associations) H-R diagram and isochrones. The thermal infrared excess is identified by comparing deviation (~3% ~15% at 1 σ level μm, respectively) between synthetic Kurucz photospheric predictions. Stars showing emission due strong lines extended nebulosity seen are...
The Deep Ecliptic Survey (DES)—a search optimized for the discovery of Kuiper belt objects (KBOs) with Blanco and Mayall 4 m telescopes at Cerro Tololo Inter-American Observatory Kitt Peak National Observatory—has covered 550 deg2 from its inception in 1998 through end 2003. This survey has a mean 50% sensitivity VR magnitude 22.5. We report here discoveries 320 designated KBOs Centaurs period 2000 March 2003 December describe improvements to our recovery procedures. Our data products needed...
We have searched for infrared excesses around a well defined sample of 69 FGK main-sequence field stars. These stars were selected without regard to their age, metallicity, or any previous detection IR excess; they median age ~4 Gyr. detected 70 um 7 at the 3-sigma confidence level. This extra emission is produced by cool material (< 100 K) located beyond 10 AU, outside ``habitable zones'' these systems and consistent with presence Kuiper Belt analogs ~100 times more emitting surface area...
<i>Context. <i/>The goal of the <i>Herschel<i/> open time programme "<i>TNOs are Cool!<i/>" is to derive physical and thermal properties for a large sample Centaurs, trans-Neptunian objects (TNOs), including resonant, classical, detached scattered disk objects.<i>Aims. <i/>Based on observations two targets we tried (i) optimise SPIRE observing technique faint (close background confusion noise), slowly moving targets; (ii) test different model techniques; (iii) determine radiometric diameter...
We have observed nearly 200 FGK stars at 24 and 70 μm with the Spitzer Space Telescope. identify excess infrared emission, including a number of cases where flux is more than 10 times brighter predicted photospheric flux, interpret these signatures as evidence debris disks in those systems. combine this sample similar published results to produce 350 main sequence AFGKM stars. The incidence 4.2+ 2.0−1.1% for 213 Sun-like (FG) 16.4+ 2.8−2.9% 225 find that rates A, F, G, K are statistically...
Spitzer photometry and spectroscopy of the star HD 69830 reveal an excess emission relative to stellar photosphere between 8 35 μm dominated by strong features attributable crystalline silicates with emitting surface area more than 1000 times that our zodiacal cloud. The spectrum closely resembles comet C/1995 O1 (Hale-Bopp). Since no is detected at 70 μm, material must be quite warm, confined within a few AU star, originate in grains low, long-wavelength emissivity, i.e., much smaller μm/2π...
Using the MIPS camera on Spitzer Space Telescope, we have searched for debris disks around 104 stars known from radial velocity studies to one or more planets. Combining this new data with 42 already published observations of planet-bearing stars, find that 14 146 systems IR excess at 24 and/or 70 μm. Only star, HD 69830, has exclusively μm, indicative warm dust in inner system analogous produced by collisions solar system's asteroid belt. For other 13 emission is stronger consistent cool...
The Kuiper Belt is a remnant from the early solar system and its size distribution contains many important constraints that can be used to test models of planet formation collisional evolution. We show, by comparing observations with theoretical models, observed well matched coagulation which start an initial planetesimal population radii about 1 km, subsequent find above R ∼ 30 km primordial, i.e., it has not been modified evolution over age system, below collisions slope use published...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
Abstract 1I/‘Oumuamua is the first confirmed interstellar body in our solar system. Here we report on observations of ‘Oumuamua made with Spitzer Space Telescope 2017 November 21–22 (UT). We integrated for 30.2 hr at 4.5 μ m (IRAC channel 2). did not detect object and place an upper limit flux 0.3 Jy (3 σ ). This implies effective spherical diameter less than [98, 140, 440] albedo greater [0.2, 0.1, 0.01] under assumption low, middle, or high thermal beaming parameter η , respectively. With...
Vera C. Rubin Observatory is a ground-based astronomical facility under construction, joint project of the National Science Foundation and U.S. Department Energy, designed to conduct multi-purpose 10-year optical survey southern hemisphere sky: Legacy Survey Space Time. Significant flexibility in strategy remains within constraints imposed by core science goals probing dark energy matter, cataloging Solar System, exploring transient sky, mapping Milky Way. The survey's massive data...
We present the Citizen Science program Active Asteroids and describe discoveries stemming from our ongoing project. Our NASA Partner is hosted on Zooniverse online platform launched 2021 August 31, with goal of engaging community in search for active asteroids -- comet-like tails or comae. also set out to identify other unusual solar system objects, such as Centaurs, quasi-Hilda asteroids, Jupiter-family comets (JFCs). objects are rare large part because they difficult identify, so we ask...
We present high spatial resolution mid- and far-infrared images of the Vega debris disk obtained with Multiband Imaging Photometer for Spitzer (MIPS). The is well resolved, its angular size much larger than found previously. radius at least 43'' (330 AU), 70'' (543 105'' (815 AU) in extent 24, 70, 160 μm, respectively. are circular, smooth, without clumpiness all three wavelengths. radial surface brightness profiles follow power laws r-3 or r-4 imply an inner boundary a 11'' ± 2'' (86 AU)....
As part of a large Spitzer/MIPS GTO program, we have searched for infrared excesses due to debris disks toward 26 FGK field stars known from radial velocity (RV) studies one or more planets. While none these show at 24um, detected 70um around 6 the 3-sigma confidence level. The are produced by cool material (< 100 K) located beyond 10 AU, well outside "habitable zones" systems and consistent with presence Kuiper Belt analogues ~100 times emitting surface area than in our own planetary...
As part of our ongoing Deep Ecliptic Survey (DES) the Kuiper belt, we report on occupation 1 : (Trojan), 4 3, 3 2, 7 4, 2 1, and 5 Neptunian mean motion resonances (MMRs). The previously unrecognized MMRs is not easily understood within standard model resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Among all resonant belt objects (KBOs), three observed members MMR discovered DES possess largest semimajor axes (a ≈ 55.4 AU), highest eccentricities (e 0.4),...
The recently discovered minor body 1I/2017 U1 (`Oumuamua) is the first known object in our Solar System that not bound by Sun's gravity. Its hyperbolic orbit (eccentricity greater than unity) strongly suggests it originated outside System; its red color consistent with substantial space weathering experienced over a long interstellar journey. We carry out an simple calculation of probability detecting such object. find observed detection rate 1I-like objects can be satisfied if average mass...
Examining the albedo distribution of near-Earth object (NEO) population allows for a better understanding relationship between absolute (H) magnitude and size, which impacts calculations size frequency impact hazards. NEO albedos also sheds light on differences Main Belt populations. We combine results from ExploreNEOs Warm Spitzer Exploration Science program with taxonomic classifications literature, publicly available data sets, new observations our concurrent spectral survey to derive...
Abstract The DECam Ecliptic Exploration Project (DEEP) is a deep survey of the trans-Neptunian solar system being carried out on 4 m Blanco telescope at Cerro Tololo Inter-American Observatory in Chile using Dark Energy Camera (DECam). By shift-and-stack technique to achieve mean limiting magnitude r ∼ 26.2, DEEP achieves an unprecedented combination area and depth, enabling quantitative leaps forward our understanding Kuiper Belt populations. This work reports results from analysis 20, 3...
Abstract We present here the DECam Ecliptic Exploration Project (DEEP), a 3 yr NOAO/NOIRLab Survey that was allocated 46.5 nights to discover and measure properties of thousands trans-Neptunian objects (TNOs) magnitudes as faint VR ∼ 27 mag, corresponding sizes small 20 km diameter. In this paper we science goals project, experimental design our survey, technical demonstration approach. The core project is “digital tracking,” in which all collected images are combined at range motion vectors...