MNRAS 000, 1–13 (2017) Preprint 22 May 2019 Compiled using MNRAS L A T E X style file v3.0 Analysis of the June 2, 2016 bolide event over Arizona Csaba Palotai, 1 ⋆ Ramanakumar Sankar, 1 Dwayne L. Free, 2 J. Andreas Howell, 3 Elena Botella 1 and Daniel Batcheldor 1 1 Department of Physics & Space Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901, USA 2 Spalding Allsky Camera Network, SkySentinel, LLC, 958 Shaw Circle, Melbourne, FL 32940, USA 3 Department of Online Science, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901, USA Accepted XXX. Received YYY; in original form ZZZ ABSTRACT On June 2, 2016 at 10h56m UTC, a −20.4 ± 0.2 magnitude superbolide was observed over Arizona. Fragments were located a few days later and the meteorites were given the name Dishchii’bikoh. We present analysis of this event based on 3 cameras and a multi-spectral sensor observations by the SkySentinel continuous fireball-monitoring camera network, supplemented by a dash cam footage and a fragmentation model. The bolide began its luminous flight at an altitude of 100.2 ± 0.4 km at coordinates φ = 34.555 ± 0.002°N planetographic latitude and λ = 110.459 ± 0.002°W longitude, and it had a pre-atmospheric velocity of 17.4 ± 0.3 km/s. The calculated orbital parameters indicate that the meteoroid did not belong to any presently known asteroid family. From our calculations, the impacting object had an initial mass of 14.8 ± 1.7 metric tonnes with an estimated initial diameter of 2.03 ± 0.12 m. Key words: meteors – meteor light curve – asteroids 1 INTRODUCTION At 10h 56m 27s UTC on June 2, 2016 a bright fireball was observed over Arizona. The American Meteor Society re- ceived 421 reports about this fireball, most of them from Ari- zona but people also witnessed this event in Utah, New Mex- ico, California, Texas, Colorado and Nevada. Sonic booms from the bolide were heard across the greater Phoenix area. Videos of the bolide from dash cams and security cameras appeared on YouTube and various media outlets. After sun- rise, videos captured the dust trail that the impactor left behind. Camera and satellite observations of meteors have been used for decades in order to help to determine the mass, trajectory and orbital parameters of the impacting body. Various satellites, NASA’s All Sky Fireball Network and the Lowell Observatory Cameras for All-Sky Meteor Surveil- lance (LO-CAMS) also recorded the Arizona bolide event. The Arizona Geological Survey’s seismic network picked up a signal near Payson that was consistent with an airburst event and according to the agency it marked the explosion of the asteroid. This was the largest observed bolide event over the continental United States since March 2010 that was reported by the Center for Near Earth Object Studies ⋆ E-mail: cpalotai@fit.edu (CsP) (CNEOS) 1 , and the fifth largest since 1988 when the agency began recording fireball data from US Government sensors. The bolide was also observed by multiple nodes of the SkySentinel’s Spalding Allsky Camera Network (Figure 1) and the recorded data allow us to characterize some of the physical properties and the likely origin of the impacting body. Here, we present our analysis of the available SkySen- tinel observations, coupled with complementary data and modeling tools. We also compare our inferred results with data reported by other sources. 2 METHODOLOGY AND INSTRUMENTATION 2.1 The SkySentinel Network Mr. R.E. Spalding (1936-2017, Sandia National Labs) de- veloped the Allsky Camera System to monitor, track, and analyze large meteor events in order to provide “ground- truth” to assist both science (NASA) and treaty monitor- ing (Nuclear-Test-Ban Treaty Organization - CTBTO) op- erations in confirming the impact of large meteor fireballs (bolides) in Earth’s atmosphere. The collected data is also used to support the refinement of the energy calculations of 1 https://cneos.jpl.nasa.gov/fireballs/, accessed December 2, 2017 © 2017 The Authors arXiv:1801.05072v2 [astro-ph.EP] 21 May 2019