(809875) 2020 BX12

Binary near-Earth asteroid April 2025 New physical and orbital parameters are given in a new paper by Fernanda Zambrano-Marin et al. (2025) February 2020 yes 809875 2020 BX 12 #FFC2E0 2020BX12 Radar.gif Radar images of 2020 BX12 reveal a small, elongated satellite orbiting around the spheroidal asteroid. 2020 BX 12 and its satellite imaged by the Arecibo Observatory in February 2020 ATLAS-MLO Mauna Loa Obs. 27 January 2020 (809875) 2020 BX 12 A10jUnf ApolloPHANEO 31 May 2020 (JD 2459000.5) 0 6.09 yr (2,224 days) 5 January 2014 2.4437 AU 0.7570 AU 1.6004 AU 0.75704 2.02 yr (739.5 d) 34.442° 0.486818 ms / day 40.067° 132.904° 70.492° 0.002061 AU 1 205 65 m9 7 8 to 3 10 kg (system)Combined mass of 2020 BX 12 and its satellite12 2.5 0.5 h9 0.3 (assumed for S-type asteroids)7 Q or Sq6 20.631 0.396 809875 2020 BX 12 is a sub-kilometer binary asteroid, classified as a near-Earth asteroid and potentially hazardous object of the Apollo group. It was discovered on 27 January 2020 by the Asteroid Terrestrial-impact Last Alert System survey at the Mauna Loa Observatory during its approach to Earth of 0.02915 AU e6km LD unit on. The Arecibo Observatory took radar images of 2020 BX 12 on 4 February 2020, which led to the discovery of a small natural satellite orbiting 360 m ft away from the asteroid. With a diameter of around 200 m ft, 2020 BX 12 is among the smallest 10% of known binary asteroids. It was the last binary asteroid discovered by the Arecibo Observatory. Discovery 2020 BX 12 was discovered on 27 January 2020 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey at the Mauna Loa Observatory in Hawaii. The ATLAS survey was designed for detecting near-Earth asteroids on approach to Earth, particularly those that may be considered potentially hazardous under circumstances where they can approach Earth from close distances. 2020 BX 12 was identified by a team of astronomers consisting of Larry Denneau, John Tonry, Aren Heinze, and Henry Weiland, who were chiefly involved in the ATLAS project. The asteroid was discovered during its approach to Earth and was at nominal distance of about 0.11 AU km mi in unit from the planet. At the time of discovery, 2020 BX 12 was located in the constellation of Puppis at an apparent magnitude of 17.6.The celestial coordinates of 2020 BX 12 at the time of discovery were 07 34 48.39 -38 14 23.2. See Puppis for constellation coordinates. The discovery of 2020 BX 12 was subsequently reported to the Minor Planet Center's Near-Earth Object Confirmation Page (NEOCP), where a preliminary orbit was calculated from additional observations conducted at multiple observatories. Follow-up observations of 2020 BX 12 spanned three days since its discovery, and the asteroid was formally announced in a Minor Planet Electronic Circular issued by the Minor Planet Center on 30 January 2020. Nomenclature Upon discovery, the asteroid was given the temporary internal designation A10jUnf. After follow up observations confirming the object, it was then given the provisional designation 2020 BX 12 by the Minor Planet Center on 30 January 2020. The provisional designation signifies the object's discovery date and year. Once 2020 BX 12 had a sufficiently long observation arc for its orbit to be accurately determined, the asteroid received the permanent minor planet number 809875 from the Minor Planet Center, making it eligible for naming. Orbit and classification 2020 BX 12 orbits the Sun at an average distance of approximately 1.60 AU e9km e9mi out in 3, taking 2.02 years to complete one full orbit. The orbit of 2020 BX 12 is highly eccentric and inclined to the ecliptic plane: it has an orbital eccentricity of 0.757 and inclination of 40 degrees, with its orbit extending from 0.76 AU at perihelion to 2.44 AU at aphelion. As it approaches perihelion, 2020 BX 12 moves above the ecliptic and comes closer to the Sun than Venus, whereas at aphelion, 2020 BX 12 moves below the ecliptic and recedes from the Sun farther out than the orbit of Mars. The orbit of 2020 BX 12 crosses that of Earth; thus it can occasionally make close approaches to Earth, making it a near-Earth object. With a semi-major axis (average orbit distance) greater than 1 AU and a perihelion distance within that of Earth, 2020 BX 12 is formally classified under the Apollo group of near-Earth asteroids. thumb|upright=1.25|left|Side view of 2020 BX 12's inclined orbit|alt=The orbit of 2020 BX12 is highly inclined to the ecliptic by 40 degrees. The asteroid's minimum orbital intersection distance (MOID) from Earth is approximately 0.002 AU e6km e6mi unit, or about 0.78 lunar distances. Having such a small Earth MOID, 2020 BX 12 is considered a potentially hazardous asteroid (PHA) by the Minor Planet Center, under the definition that PHAs have Earth MOIDs less than 0.05 AU and absolute magnitudes under 22. Despite this, 2020 BX 12 will not make any close Earth encounters within 15 lunar distances or 0.04 AU e6km e6mi unit over the next 200 years, and the asteroid has not been listed by the JPL Sentry Risk Table 2020 y. On 12 February 2020, a team of astronomers identified 2020 BX 12 in several precovery images taken by the Pan-STARRS 1 survey, with the earliest images dating back to 5 January 2014. The observation arc of these precovery images spanned over six years, long enough for astronomers to refine and calculate 2020 BX 12's orbit with accuracy. This greatly reduced uncertainties in the asteroid's orbit, reducing its uncertainty parameter from 8 to 1. February 2020 the observation arc of 2020 BX 12 spans 6.09 years or 2,224 days, with an orbit uncertainty parameter of 0 according to the JPL Small-Body Database. left 2020 Earth approach On 3 February 2020 at 18:56 UTC, 2020 BX 12 passed 0.02915 AU e6km e6mi unit 3, or 11.35 lunar distances, from Earth. During its close approach to Earth, the asteroid approached Earth at a rate of 25.3 km/s mph and its apparent visual brightness peaked around magnitude 15.7, which is too faint to be seen with the naked eye. At closest approach the asteroid's apparent motion in the sky was 1.2 degrees per hour, and it was in the constellation of Cetus, with an apparent magnitude of 16 and an angular separation of 20 degrees from the Moon.The celestial coordinates of 2020 BX 12 at 19:00 UTC are 03 08 29.788 +05 03 41.65. See Cetus for constellation coordinates. The February 2020 encounter by 2020 BX 12 provided an opportunity for radar observatories to study the asteroid's characteristics in detail. 2020 BX 12 was the first radar target observed by the Arecibo Observatory in Puerto Rico since the one-month shutdown of observatory operations due to a series of earthquakes in the southern region of Puerto Rico in December 2019 and January 2020. Radar observations of 2020 BX 12 were conducted on 4 February 2020 by a team of astronomers led by Luisa Zambrano-Marín. Over a two-day observation period, astronomers measured the asteroid's size, shape, and rotation, and discovered a small satellite. After the February 2020 encounter, 2020 BX 12 passed perihelion on 21 March 2020. During its egress from perihelion, the asteroid made its closest approach to Mars on 28 June 2020, at a distance of 0.042 AU e6km e6mi unit. Future approaches Over the course of its orbit in the next 200 years, 2020 BX 12 will continue to pass by Earth, though it will not make any approaches as close as the February 2020 encounter that would otherwise warrant attention. The last Earth encounter by 2020 BX 12 from a closer distance was on 1 February 1931, when the asteroid approached Earth from a distance of 0.009 AU e6km e6mi unit, or 3.5 lunar distances. An Earth encounter by 2020 BX 12 occurred in February 2022 and another occurred in 2024, with approach distances of 0.18 AU and 0.34 AU, respectively. Physical characteristics High-resolution delay-Doppler radar imaging by the Arecibo Observatory in February 2020 has shown that 2020 BX 12 is a spheroidal object with a diameter of 205 ± 65 m ft 2. This spheroidal shape is commonly seen in other near-Earth objects, such as 308635 2005 YU 55 and 101955 Bennu. Based on the asteroid's estimated diameter and the bandwidth of radar signals reflected from the asteroid, the rotation period of 2020 BX 12 is estimated to be between 2 and 3 hours—close to the 2.2-hour spin barrier at which asteroids tend to break apart due to excessive centrifugal forces.2, 11 Like other binary near-Earth asteroids, the rapid rotation of 2020 BX 12 suggests that it was sped up by the YORP effect and may have undergone rotational breakup, which led to the formation of its satellite.1–2, 12 The axial tilt or direction of 2020 BX 12's rotational pole is unknown and could not be constrained by Arecibo's radar observations, however.9 Astronomical spectroscopy by the 10.4 m ft on Gran Telescopio Canarias in February 2024 has shown that the visible and near-infrared spectrum of 2020 BX 12 most closely matches those of Q- and Sq-type asteroids,5–6 indicating that it is predominantly made of silicate minerals.12 In particular, 2020 BX 12 appears reddish in the visible spectrum until the wavelength of 0.7 um, and exhibits a spectral absorption band from wavelengths of 0.75 to 1.05 um, indicating the presence of olivine and pyroxene.7, 12 The silicaceous composition and spectral type of 2020 BX 12 is commonly seen in near-Earth asteroids.12 The geometric albedo of 2020 BX 12 has not been directly measured, but is inferred to be around 0.3 based on its spectral type.7 Satellite Satellite File:2020BX12 Arecibo Radar.png The satellite of 2020 BX12 appears as a small, elongated object separate from the asteroid in radar images. Two radar images of 2020 BX 12 and its satellite taken by the Arecibo Observatory in February 2020 Luisa F. Zambrano-Marín et al.Planetary Radar Science Groupdiscovery Arecibo Obs. 4 February 2020 (809875) 2020 BX 12 9 400 m > (lower limit) 40 h > (lower limit) 9 50 25 m (likely synchronous)6 h > (lower limit) Q or Sq9 The satellite of 2020 BX 12 was discovered in Arecibo radar observations conducted by a team of astronomers consisting of Luisa Zambrano-Marín along with other members of the Planetary Radar Science Group.discovery The Planetary Radar Science Group's press release page credits the satellite's discovery to Luisa Fernanda Zambrano-Marín, Sean Marshall, Anne Virkki, Dylan Hickson, Anna McGilvray, Johbany Lebron, and Israel Cabrera of the Arecibo Observatory. With the discovery of a satellite around 2020 BX 12, the mass and density of the primary body can be determined from the satellite's orbit. The satellite may have formed as a result of rotational fission or mass ejection of the primary body, since 2020 BX 12 along with other binary near-Earth asteroids have been observed to have rapid rotation periods and spheroidal shapes. Physical characteristics With a diameter of 50 ± 25 m ft, the satellite is less than one third of 2020 BX 12's diameter.12 The satellite's shape is unknown as it was not resolved in Arecibo's radar imagery.12 Orbit and rotation From radar images taken on 5 February 2020, the separation distance between the satellite and the primary body is estimated to be about 360 m ft, or 4.4 times the radius of the 2020 BX 12 primary. The orbital period of the satellite is thought to be around 45–50 hours, with the best-fit period being 47 hours. However, another possible orbital period of 15–16 hours has not been yet been ruled out, due to projection effects of radar images. Radar observations by Arecibo suggest the satellite is likely tidally locked to the primary body, with its rotation period being synchronous with its orbital period. However, uncertainties remain in measurements of the satellite's rotation period, thus an upper limit to its period was placed at 49 hours. Notes References 2020-02-07 last obs. JPL Small-Body Database Browser: 2020 BX12 https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3989285 Jet Propulsion Laboratory 11 February 2020 2020 BX12 Minor Planet Center International Astronomical Union http://www.minorplanetcenter.net/db_search/show_object?object_id=2020+BX12 11 February 2020 Ephemerides at discovery 2020BX12 Ephemerides https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=2020BX12&oc=500&y0=2020&m0=1&d0=27&h0=9&mi0=02&y1=2020&m1=1&d1=27&h1=9&mi1=07&ti=1.0&tiu=minutes Near Earth Objects – Dynamic Site Department of Mathematics, University of Pisa, Italy 11 February 2020 Ephemerides at 3 February 2020 approach 2020BX12 Ephemerides https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=2020BX12&oc=500&y0=2020&m0=2&d0=2&h0=5&mi0=0&y1=2020&m1=2&d1=4&h1=6&mi1=0&ti=0.5&tiu=hours Near Earth Objects – Dynamic Site Department of Mathematics, University of Pisa, Italy 11 February 2020 2020 BX12 https://neoexchange.lco.global/target/56418/ NEO Exchange Las Cumbres Observatory 27 January 2020 11 February 2020 "Pseudo-MPEC" for A10jUnf https://www.projectpluto.com/neocp2/mpecs/A10jUnf.htm Project Pluto 30 January 2020 15 February 2020 dead https://web.archive.org/web/20200216064627/https://www.projectpluto.com/neocp2/mpecs/A10jUnf.htm 16 February 2020 How Are Minor Planets Named? https://minorplanetcenter.net/iau/info/HowNamed.html Minor Planet Center International Astronomical Union 12 February 2020 Binary Asteroids in the Near-Earth Object Population etal J. L. Margot M. C. Nolan L. A. M. Benner S. J. Ostro R. F. Jurgens J. F. Giorgini 24 May 2002 Science 296 1445–1448 5572 10.1126/science.1072094 2002Sci...296.1445M 11951001 8768432 The Shape and Spin Distributions of Near-Earth Asteroids Observed with the Arecibo Radar System https://www.lpi.usra.edu/meetings/acm2012/pdf/6340.pdf Patrick A. Taylor Ellen S. Howell Ellen Howell Michael C. Nolan Abby A. Thane May 2012 Asteroids, Comets, Meteors Lunar and Planetary Institute Niigata, Japan 1667 6340 2012LPICo1667.6340T ATLAS: A High-Cadence All-Sky Survey System etal J. L. Tonry L. Denneau A. N. Heinze B. Stalder K. W. Smith S. J. Smartt June 2018 Publications of the Astronomical Society of the Pacific 130 26 988 10.1088/1538-3873/aabadf 1802.00879 2018PASP..130f4505T 59135328 MPEC 2020-B281: 2020 BX12 https://www.minorplanetcenter.net/mpec/K20/K20BS1.html etal L. Denneau Minor Planet Electronic Circular Minor Planet Center 30 January 2020 11 February 2020 2020 BX12 http://www.johnstonsarchive.net/astro/astmoons/am2020bx12.html Wm. Robert Johnston Johnston's Archive 7 February 2020 11 February 2020 Discovery Announcement of Binary System 2020 BX12 http://www.naic.edu/~pradar/press/2020BX12.php A. K. Virkki Planetary Radar Science Group NAIC-Arecibo Observatory 10 February 2020 11 February 2020 12 February 2020 https://web.archive.org/web/20200212231931/http://www.naic.edu/~pradar/press/2020BX12.php dead An Asteroid Totally Just Mooned Earth https://www.sciencealert.com/an-asteroid-literally-just-mooned-earth Michelle Starr ScienceAlert 11 February 2020 11 February 2020 Arecibo Observatory Discovers Moon Orbiting Near-Earth Asteroid https://www.ucf.edu/news/arecibo-observatory-discovers-moon-orbiting-near-earth-asteroid/ Tracy Becker UCF Today University of Central Florida 12 February 2020 13 February 2020 MPEC 2020-C132: 2020 BX12 https://minorplanetcenter.net/mpec/K20/K20CD2.html etal J. Bulger Minor Planet Electronic Circular Minor Planet Center 12 January 2020 12 February 2020 Scientists just watched a newfound asteroid zoom by Earth. Then they saw its moon https://www.space.com/near-earth-binary-asteroid-2020-bx12-has-moon.html Meghan Bartels Space.com 13 February 2020 13 February 2020 Astronomers spy near-Earth asteroid that has its own moon https://www.washingtonpost.com/science/2020/02/14/astronomers-spy-near-earth-asteroid-that-has-its-own-moon/ Ben Guarino Washington Post 14 February 2020 17 February 2020 Sentry: Earth Impact Monitoring https://cneos.jpl.nasa.gov/sentry/details.html#?des=2020%20BX12 Center for Near Earth Object Studies Jet Propulsion Laboratory 11 February 2020 PHA (Potentially Hazardous Asteroid) https://cneos.jpl.nasa.gov/glossary/PHA.html Center for Near Earth Object Studies Jet Propulsion Laboratory 11 February 2020 etal Luisa Fernanda Zambrano-Marin Sean E. Marshall Ellen S. Howell Julia de León Noemi Pinilla-Alonso Anne K. Virkki 2020 BX12—The Last Binary Asteroid Discovered at Arecibo The Planetary Science Journal December 2025 6 4 91 free 10.3847/PSJ/adbe39 2025PSJ.....6...91Z 10138/601896 free External links Arecibo Observatory Discovers Moon Orbiting Near-Earth Asteroid, Tracy Becker, University of Central Florida, 12 Feb 2020 An Asteroid Totally Just Mooned Earth, Michelle Starr, ScienceAlert, 11 Feb 2020 Discovery Announcement of Binary System 2020 BX12 https://web.archive.org/web/20200212231931/http://www.naic.edu/~pradar/press/2020BX12.php 12 February 2020 , Planetary Radar Science Group, 10 Feb 2020 2020BX12 – Summary, ESA Space Situational Awareness, 10 Feb 2020 2020bx12 809875 (809875) 2020 BX 12 Astronomy Outer Space Category:Apollo asteroids Category:Discoveries by ATLAS Category:Potentially hazardous asteroids Category:Binary asteroids Category:Radar-imaged asteroids 20200127 20200127