@article{c2361645e52d4f81902b0c8bdbaab956,
title = "Radar and Optical Characterization of Near-Earth Asteroid 2019 OK",
abstract = "We conducted radar observations of near-Earth asteroid 2019 OK on 2019 July 25 using the Arecibo Observatory S-band (2380 MHz, 12.6 cm) planetary radar system. Based on Arecibo and optical observations the apparent diameter is between 70 and 130 m. Combined with an absolute magnitude of H = 23.3 ± 0.3, the optical albedo of 2019 OK is likely between 0.05 and 0.17. Our measured radar circular polarization ratio of μC = 0.33 ± 0.03 indicates 2019 OK is likely not a V- or E-type asteroid and is most likely a C- or S-type. The measured radar echo bandwidth of 39 ± 2 Hz restricts the apparent rotation period to be approximately between 3 minutes (0.049 hr, D = 70 m) and 5 minutes (0.091 h, D = 130 m). Together, the apparent diameter and rotation period suggest that 2019 OK is likely not a rubble-pile body bound only by gravity. 2019 OK is one of a growing number of fast-rotating near-Earth asteroids that require some internal strength to keep them from breaking apart.",
author = "Zambrano-Marin, {Luisa Fernanda} and Howell, {Ellen S.} and Taylor, {Patrick A.} and Marshall, {Sean E.} and Maxime Devog{\`e}le and Virkki, {Anne K.} and Hickson, {Dylan C.} and Rivera-Valent{\'i}n, {Edgard G.} and Venditti, {Flaviane C.F.} and Giorgini, {Jon D.}",
note = "Funding Information: This research was funded by NASA through the Near-Earth Object Observations program under grant No. 80NSSC19K0523. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by the University of Central Florida in alliance with Yang Enterprises, Inc. and Ana G. Mendez University System. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This work made use of the NASA/JPL Horizons On-Line Ephemeris System and NASA{\textquoteright}s Astrophysics Data System Bibliographic Services. The authors would like to thank the Arecibo Observatory staff, especially Mr. Victor Negron and Mr. Juan Marrero, as well as the Arecibo Observatory Management Team. The authors thank the anonymous reviewers who helped improve this manuscript. Facility: The Arecibo Observatory. Software: OSOD (Ostro 1993), Radar Decode. Funding Information: This research was funded by NASA through the Near-Earth Object Observations program under grant No. 80NSSC19K0523. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by the University of Central Florida in alliance with Yang Enterprises, Inc. and Ana G. Mendez University System. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This work made use of the NASA/JPL Horizons On-Line Ephemeris System and NASA{\textquoteright}s Astrophysics Data System Bibliographic Services. The authors would like to thank the Arecibo Observatory staff, especially Mr. Victor Negron and Mr. Juan Marrero, as well as the Arecibo Observatory Management Team. The authors thank the anonymous reviewers who helped improve this manuscript. Publisher Copyright: {\textcopyright} 2022. The Author(s). Published by the American Astronomical Society.",
year = "2022",
month = jun,
day = "1",
doi = "10.3847/PSJ/ac63cd",
language = "English (US)",
volume = "3",
journal = "Planetary Science Journal",
issn = "2632-3338",
publisher = "IOP Publishing Ltd.",
number = "6",
}