A5030765992- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Isotope Analysis in Ecology
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Space Exploration and Technology
- Particle physics theoretical and experimental studies
- Graph Theory and Algorithms
- Web Data Mining and Analysis
- Space exploration and regulation
- Particle Accelerators and Free-Electron Lasers
- Space Satellite Systems and Control
- Neutrino Physics Research
- Particle Detector Development and Performance
- Radio Astronomy Observations and Technology
- Data Management and Algorithms
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Distributed and Parallel Computing Systems
- Atmospheric Ozone and Climate
California Institute of Technology
2012-2017
The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and Scattered Disk Objects in the thermal infrared, including 15 discoveries that were new. We present analyses of these observations to estimate sizes mean optical albedos. find albedos 0.08 +/- 0.04 for entire data set. Thermal fits yield average beaming parameters 0.9 0.2 are similar both SDO Centaur sub-classes. Biased cumulative size distributions size-frequency distribution power law indices ~ -1.7 0.3. also reveal a...
The Palomar Transient Factory (PTF) is a multi-epochal robotic survey of the northern sky that acquires data for scientific study transient and variable astrophysical phenomena. camera telescope provide wide-field imaging in optical bands. In five years operation since first light on December 13, 2008, images taken with Mould-R SDSS-g' filters have been routinely acquired nightly basis (weather permitting), two different H-alpha were installed May 2011 (656 nm 663 nm). PTF image-processing...
We report positions, velocities and metallicities of 50 ab-type RR Lyrae (RRab) stars observed in the vicinity Orphan stellar stream. Using about 30 RRab classified as being likely members stream, we study metallicity spatial extent find that stream have a wide range metallicities, from -1.5 dex to -2.7 dex. The average is -2.1 dex, identical value obtained by Newberg et al. (2010) using blue horizontal branch stars. most distant parts (40-50 kpc Sun) are 0.3 more metal-poor than closer...
We fit 54,296 sparsely-sampled asteroid lightcurves in the Palomar Transient Factory to a combined rotation plus phase-function model. Each lightcurve consists of 20+ observations acquired single opposition. Using 805 asteroids our sample that have reference periods literature, we find reliability fitted is complicated function period, amplitude, apparent magnitude and other attributes. 805-asteroid ground-truth sample, train an automated classifier estimate (along with manual inspection)...
Two dedicated asteroid rotation-period surveys have been carried out using data taken on January 6-9 and February 20-23 of 2014 by the Intermediate Palomar Transient Factory (iPTF) in $R$~band with $\sim 20$-min cadence. The total survey area covered 174~deg$^2$ ecliptic plane. Reliable rotation periods for 1,438 asteroids are obtained from a larger set 6,551 mostly main-belt asteroids, each $\geq 10$~detections. Analysis 1751, PTF based, reliable clearly shows "spin barrier" at 2$~hours...
We present an observational and dynamical study of newly discovered main-belt comet 313P/Gibbs. find that the object is clearly active both in observations obtained 2014 precovery 2003 by Sloan Digital Sky Survey, strongly suggesting its activity sublimation-driven. This conclusion supported a photometric analysis showing increase total brightness over observing period, dust modeling results emission persists at least three months during periods, where we start dates for no later than July...
The Palomar Transient Factory (PTF) is a synoptic survey designed to explore the transient and variable sky in wide variety of cadences. We use PTF observations fields that were observed multiple times (>=10) per night, for several nights, find asteroids, construct their lightcurves measure rotation periods. Here we describe pipeline achieve these goals present results from first four (overlapping) analyzed as part this program. These fields, which cover an area 21 deg^2, on nights with...
Cometary activity in main-belt asteroids probes the ice content of these objects and provides clues to history volatiles inner Solar system. We search Palomar Transient Factory survey derive upper limits on population size active comets (MBCs). From data collected from 2009 March through 2012 July, we extracted ∼2 million observations ∼220 thousand known (40 per cent population, down ∼1-km diameter) discovered 626 new multinight linked detections. formally quantify ‘extendedness’ a...
A new asteroid rotation period survey have been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg$^2$ in ecliptic plane, were observed $R$ band with a cadence $\sim$20 min during February 15--18, 2013. We detected 2500 known asteroids diameter range 0.5 km $\leq D \leq$ 200 km. Of these, 313 objects had highly reliable periods and exhibited "spin barrier" at $\sim2$ hours. In contrast to flat spin rate distribution 3 15...
Near-Earth asteroids (NEAs) in the 1-100 meter size range are estimated to be $\sim$1,000 times more numerous than $\sim$15,000 currently-catalogued NEAs, most of which 0.5-10 kilometer range. Impacts from 10-100 NEAs not statistically life-threatening but may cause significant regional damage, while 1-10 with low velocities relative Earth compelling targets for space missions. We describe implementation and initial results a real-time NEA-discovery system specialized detection small, high...
Asteroids of size larger than 150 m generally do not have rotation periods smaller 2.2 hr. This spin cutoff is believed to be due the gravitationally bound rubble-pile structures asteroids. Rotation with exceeding this critical value will cause asteroid breakup. Up until now, only one object, 2001 OE84, has been found an exception cutoff. We report discovery a new super-fast rotator, (335433) 2005 UW163, spinning period 1.290 hr and light curve variation r' ∼ 0.8 mag from observations made...
We present ultraviolet (UV) photometry (near-UV (NUV) band, 180–280 nm) of 405 asteroids observed serendipitously by GALEX from 2003 to 2012. All in this sample were detected at least twice. Unambiguous visible-color-based taxonomic labels (C type versus S type) exist for 315 these asteroids; these, thermal-infrared-based diameters are available 245. derive NUV − V color using two independent models predict the visual magnitude each NUV-detection epoch. Both produce distributions which types...