Observational Investigation of the 2013 Near-Earth Encounter by Asteroid (367943) Duende
arXiv:1911.00609 · doi:10.1016/j.icarus.2019.113519
Abstract
On 15 February 2013, the asteroid 367943 Duende (2012 DA14) experienced a near-Earth encounter at an altitude of 27,700 km or 4.2 Earth radii. We present here the results of an extensive, multi-observatory campaign designed to probe for spectral and/or rotational changes to Duende due to gravitational interactions with the Earth during the flyby. Our spectral data reveal no changes within the systematic uncertainties of the data. Post-flyby lightcurve photometry places strong constraints on the rotation state of Duende, showing that it is in non-principal axis rotation with fundamental periods of P_1 = 8.71 +/- 0.03 and P_2 = 23.7 +/- 0.2 hours. Multiple lightcurve analysis techniques, coupled with theoretical considerations and delay-doppler radar imaging, allows us to assign these periods to specific rotational axes of the body. In particular we suggest that Duende is now in a non-principal, short axis mode rotation state with a precessional period equal to P_1 and oscillation about the symmetry axis at a rate equal to P_2. Temporal and signal-to-noise limitations inherent to the pre-flyby photometric dataset make it difficult to definitively diagnose whether these periods represent a change imparted due to gravitational torques during the flyby. However, based on multiple analysis techniques and a number of plausibility arguments, we suggest that Duende experienced a rotational change during the planetary encounter with an increase in its precessional rotation period. Our preferred interpretation of the available data is that the precession rate increased from 8.4 hours prior to the flyby to 8.7 hours afterwards. A companion paper by Benson et al. (2019) provides a more detailed dynamical analysis of this event and compares the data to synthetic lightcurves computed from a simple shape model of Duende. (abbreviated abstract)
arXiv comment50 pages (double spaced), 12 figures, 5 tables, accepted to Icarus
References in corpus (14)
- The USNO-B Catalog
- Las Cumbres Observatory Global Telescope Network
- The PPMXL catalog of positions and proper motions on the ICRS. Combining USNO-B1.0 and 2MASS
- The Third US Naval Observatory CCD Astrograph Catalog (UCAC3)
- Phase reddening on near-Earth asteroids: Implications for mineralogical analysis, space weathering and taxonomic classification
- An Early Warning System for Asteroid Impact
- Numerical predictions of surface effects during the 2029 close approach of asteroid 99942 Apophis
- The Centurion 18 telescope of the Wise Observatory
- Photometry and Spin Rate Distribution of Small-Sized Main Belt Asteroids
- Limits on the Size and Orbit Distribution of Main Belt Comets
- Colors of Dynamically Associated Asteroid Pairs
- The Need for Speed in Near-Earth Asteroid Characterization
- Visible and near-infrared observations of asteroid 2012 DA14 during its closest approach of February 15, 2013
- Component periods of non-principal-axis rotation and their manifestations in the lightcurves of asteroids and bare cometary nuclei