Peter Vereš

The Pan-STARRS Moving Object Processing System

ABSTRACT.We describe the Pan-STARRS Moving Object Processing System (MOPS), a modern software package that produces automatic asteroid discoveries and identifications from catalogs of transient detections from next-generation astronomical survey telescopes. MOPS achieves >99.5%>99.5% efficiency in producing orbits from a synthetic but realistic population of asteroids whose measurements were simulated for a Pan-STARRS4-class telescope. Additionally, using a nonphysical grid population, we demonstrate that MOPS can detect populations of currently unknown objects such as interstellar asteroids. MOPS has been adapted successfully to the prototype Pan-STARRS1 telescope despite differences in expected false detection rates, fill-factor loss, and relatively sparse observing cadence compared to a hypothetical Pan-STARRS4 telescope and survey. MOPS remains highly efficient at detecting objects but drops to 80% efficiency at producing orbits. This loss is primarily due to configurable MOPS processing limits that a...

Discovery of Main-Belt Comet P/2006 VW139 by Pan-STARRS1

The main-belt asteroid (300163) 2006 VW139 (later designated P/2006 VW139) was discovered to exhibit comet-like activity by the Pan-STARRS1 (PS1) survey telescope using automated point-spread-function analyses performed by PS1’s Moving Object Processing System. Deep follow-up observations show both a short (∼10 �� ) antisolar dust tail and a longer (∼60 �� ) dust trail aligned with the object’s orbit plane, similar to the morphology observed for another main-belt comet (MBC), P/2010 R2 (La Sagra), and other well-established comets, implying the action of a long-lived, sublimation-driven emission event. Photometry showing the brightness of the near-nucleus coma remaining constant over ∼30 days provides further evidence for this object’s cometary nature, suggesting it is in fact an MBC, and not a disrupted asteroid. A spectroscopic search for CN emission was unsuccessful, though we find an upper limit CN production rate of QCN 100 Myr, while a search for a potential asteroid family around the object reveals a cluster of 24 asteroids within a cutoff distance of 68 m s −1 .A t 70 ms −1 , this cluster merges with the Themis family, suggesting that it could be similar to the Beagle family to which another MBC, 133P/Elst-Pizarro, belongs.

Detection of Earth-impacting asteroids with the next generation all-sky surveys

Abstract We have performed a simulation of a next generation sky survey’s (Pan-STARRS 1) efficiency for detecting Earth-impacting asteroids. The steady-state sky-plane distribution of the impactors long before impact is concentrated towards small solar elongations (Chesley, S.R., Spahr T.B., 2004. In: Belton, M.J.S., Morgan, T.H., Samarashinha, N.H., Yeomans, D.K. (Eds.), Mitigation of Hazardous Comets and Asteroids. Cambridge University Press, Cambridge, pp. 22–37) but we find that there is interesting and potentially exploitable behavior in the sky-plane distribution in the months leading up to impact. The next generation surveys will find most of the dangerous impactors (>140xa0m diameter) during their decade-long survey missions though there is the potential to miss difficult objects with long synodic periods appearing in the direction of the Sun, as well as objects with long orbital periods that spend much of their time far from the Sun and Earth. A space-based platform that can observe close to the Sun may be needed to identify many of the potential impactors that spend much of their time interior to the Earth’s orbit. The next generation surveys have a good chance of imaging a bolide like 2008 TC 3 before it enters the atmosphere but the difficulty will lie in obtaining enough images in advance of impact to allow an accurate pre-impact orbit to be computed.

Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - preliminary results

Abstract We present the results of a Monte Carlo technique to calculate the absolute magnitudes (H) and slope parameters (G) of ∼240,000 asteroids observed by the Pan-STARRS1 telescope during the first 15xa0months of its 3-year all-sky survey mission. The system’s exquisite photometry with photometric errors ≲ 0.04 mag , and well-defined filter and photometric system, allowed us to derive accurate H and G even with a limited number of observations and restricted range in phase angles. Our Monte Carlo method simulates each asteroid’s rotation period, amplitude and color to derive the most-likely H and G, but its major advantage is in estimating realistic statisticalxa0+xa0systematic uncertainties and errors on each parameter. The method was tested by comparison with the well-established and accurate results for about 500 asteroids provided by Pravec et al. (Pravec, P. et al. [2012]. Icarus 221, 365–387) and then applied to determining H and G for the Pan-STARRS1 asteroids using both the Muinonen et al. (Muinonen, K. et al. [2010]. Icarus 209, 542–555) and Bowell et al. (Bowell, E. et al. [1989]. Asteroids III, Chapter Application of Photometric Models to Asteroids. University of Arizona Press, pp. 524–555) phase functions. Our results confirm the bias in MPC photometry discovered by Juric et al. (Juric, M. et al. [2002]. Astrophys. J. 124, 1776–1787).

Main-belt Comet P/2012?T1 (PANSTARRS)

United States. National Aeronautics and Space Administration (NASA Astrobiology Institute, cooperative agreement NNA09DA77A)

Improved Asteroid Astrometry and Photometry with Trail Fitting

Asteroid detections in astronomical images may appear as trails due to a combination of their apparent rate of motion and exposure duration. Nearby asteroids in particular typically have high apparent rates of motion and acceleration. Their recovery, especially on their discovery apparition, depends upon obtaining good astrometry from the trailed detections. We present an analytic function describing a trailed detection under the assumption of a Gaussian point spread function (PSF) and constant rate of motion. We have fit the function to both synthetic and real trailed asteroid detections from the Pan-STARRS1 survey telescope to obtain accurate astrometry and photometry. For short trails our trailing function yields the same astrometric and photometry accuracy as a functionally simpler two-dimensional Gaussian but the latter underestimates the length of the trail—a parameter that can be important for measuring the objects rate of motion and assessing its cometary activity. For trails longer than about 10 pixels (~3× PSF) our trail fitting provides ~3× better astrometric accuracy and up to two magnitudes improvement in the photometry. The trail fitting algorithm can be implemented at the source detection level for all detections to provide trail length and position angle that can be used to reduce the false tracklet rate.

The main-belt comets: The Pan-STARRS1 perspective

Abstract We analyze a set of 760xa0475 observations of 333xa0026 unique main-belt objects obtained by the Pan-STARRS1 (PS1) survey telescope between 2012 May 20 and 2013 November 9, a period during which PS1 discovered two main-belt comets, P/2012 T1 (PANSTARRS) and P/2013 R3 (Catalina-PANSTARRS). PS1 comet detection procedures currently consist of the comparison of the point spread functions (PSFs) of moving objects to those of reference stars, and the flagging of objects that show anomalously large radial PSF widths for human evaluation and possible observational follow-up. Based on the number of missed discovery opportunities among comets discovered by other observers, we estimate an upper limit comet discovery efficiency rate of ∼70% for PS1. Additional analyses that could improve comet discovery yields in future surveys include linear PSF analysis, modeling of trailed stellar PSFs for comparison to trailed moving object PSFs, searches for azimuthally localized activity, comparison of point-source-optimized photometry to extended-source-optimized photometry, searches for photometric excesses in objects with known absolute magnitudes, and crowd-sourcing. Analysis of the discovery statistics of the PS1 survey indicates an expected fraction of 59 MBCs per 10 6 outer main-belt asteroids (corresponding to a total expected population of ∼140 MBCs among the outer main-belt asteroid population with absolute magnitudes of 12 H V 19.5 ), and a 95% confidence upper limit of 96 MBCs per 10 6 outer main-belt asteroids (corresponding to a total of ∼230 MBCs), assuming a detection efficiency of 50%. We note however that significantly more sensitive future surveys (particularly those utilizing larger aperture telescopes) could detect many more MBCs than estimated here. Examination of the orbital element distribution of all known MBCs reveals an excess of high eccentricities ( 0.1 e 0.3 ) relative to the background asteroid population. Theoretical calculations show that, given these eccentricities, the sublimation rate for a typical MBC is orders of magnitude larger at perihelion than at aphelion, providing a plausible physical explanation for the observed behavior of MBCs peaking in observed activity strength near perihelion. These results indicate that the overall rate of mantle growth should be slow, consistent with observational evidence that MBC activity can be sustained over multiple orbit passages.

All-Sky Video Orbits of Lyrids 2009

We report observational results of the Lyrid meteor shower observed by the double station all-sky video system in the night of April 21/22, 2009 at the Astronomical and Geophysical Observatory of the Comenius University in Modra and Arboretum, Tesarske Mlyv{n}any, Slovakia. This observation was the first test of the double stations and orbit determination method within the frame of the new Slovak Video Meteor Network (SVMN). We present the whole set of 17 observed orbits of Lyrids as well as the five most precise orbits in detail form. The comparison with the known datasets, precise photographic IAU MDC and SonotaCo video orbits, demonstrate quite good consistency and similar quality.

Tidal disruption of NEAs – a case of Příbram meteorite

This work studies the dynamical evolution of a possible meteor stream along the orbit of the Pv{r}{i}bram meteorite, which originated in the tidal disruption of the putative rubble-pile-like parent body during a close approach to the Earth. We assumed the disruption at the time when the ascending or descending node of the parent orbit was close to the Earths orbit. In the last 5000 years, the Pv{r}{i}bram orbit has crossed the Earth orbit twice. It happened about 4200 years and 3300 years ago. In both cases, we modeled the release of particles from the simplified model of rotating asteroid, and traced their individual orbital evolution to the current date. It takes several hundred years to spread released meteoroids along the entire orbit of the parent body. Even today, the stream would be relatively narrow. nConsidering a model parent body with physical parameters of the asteroid Itokawa, the complete disintegration of the object produced 3.8

Tidal disruption of NEAs - a case of P\v{r}\'ibram

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