Discovery [1] [2] | |
---|---|
Discovered by | Pan-STARRS 1 |
Discovery site | Haleakalā Obs. |
Discovery date | 17 September 2020 |
Designations | |
2020 SO | |
P116rK2 [3] | |
NEO · Apollo (May 2020) [4] Atira (Dec 2020) [2] | |
Orbital characteristics [2] | |
Epoch 17 December 2020 (JD 2459200.5) | |
Uncertainty parameter 2 | |
Observation arc | 167 days |
Earliest precovery date | 19 August 2020 |
Aphelion | 0.988 AU |
Perihelion | 0.985 AU |
0.986 AU | |
Eccentricity | 0.00181 |
0.98 yr (357.9 d) | |
276.388° | |
1° 0m 21.877s / day | |
Inclination | 0.1389° |
216.656° | |
311.989° | |
Earth MOID | 0.01628 AU (May 2020) [4] 0.00106 AU (Dec 2020) |
Physical characteristics | |
Mean diameter | 6–12 m (assumed) [5] |
0.0026080±0.0000001 h [6] or 9.39 s | |
22.4 (at discovery) [1] 14.1 (1 Dec 2020) [7] | |
27.66±0.34 [4] 28.43 [2] | |
2020 SO [lower-alpha 1] is a near-Earth object identified to be the Surveyor 2 Centaur rocket booster launched on 20 September 1966. The object was discovered by the Pan-STARRS 1 survey at the Haleakala Observatory on 17 September 2020. It was initially suspected to be an artificial object due to its low velocity relative to Earth and later on the noticeable effects of solar radiation pressure on its orbit. Spectroscopic observations by NASA's Infrared Telescope Facility in December 2020 found that the object's spectrum is similar to that of stainless steel, confirming the object's artificial nature. [8] Following the object's confirmation as space debris, the object was removed from the Minor Planet Center's database on 19 February 2021. [9]
As it approached Earth, the trajectory indicated the geocentric orbital eccentricity was less than 1 by 15 October 2020, [10] [lower-alpha 2] and the object became temporarily captured on 8 November when it entered Earth's Hill sphere. [11] It entered via the outer Lagrange point L2 and will exit via Lagrange point L1. During its geocentric orbit around Earth, 2020 SO made a close approach to Earth on 1 December 2020 at a perigee distance of approximately 0.13 lunar distances (50,000 km; 31,000 mi). [4] It also made another close approach on 2 February 2021, at a perigee distance of approximately 0.58 LD (220,000 km; 140,000 mi). [4] Since discovery the time of uncertainty for February 2021 closest approach to Earth was reduced from ±3 days to less than 1 minute. [4] It left Earth's Hill sphere at around 8 March 2021. [12] [lower-alpha 2]
Paul Chodas of the Jet Propulsion Laboratory suspects 2020 SO of being the Surveyor 2 Centaur rocket booster, launched on 20 September 1966. [11] [12] [13] The Earth-like orbit and low relative velocity suggest a possible artificial object. Spectroscopy may help determine if it is covered in white titanium dioxide paint. [14] Goldstone radar will make bistatic observations transmitting from the 70-meter DSS-14 and receiving at the 34-meter DSS-13. [15] As a result of the bistatic DSS-14/RT-32 radar observations, a rotation period of about 9.5 seconds was obtained, [16] which corresponds to the photometric observations. [6] Obtained range-Doppler radar images [16] confirm that the object has an elongated shape with a length of about 10 meters and a width of about 3 meters.
Around the time of closest approach on 1 December 2020, the object was only brightened to about apparent magnitude 14.1, [7] and required a telescope with roughly a 150mm (6") objective lens to be seen visually. [17] It displays a large light curve amplitude of 2.5 magnitudes, signifying a highly elongated shape or albedo variations on its surface. It has a rotation period of approximately 9 seconds. [18]
At the time of its discovery, 2020 SO had unremarkable motion typical of a main-belt asteroid.[ citation needed ] However, the four observations that Pan-STARRS obtained over the course of 1.4 hours showed non-linear motion due to the rotation of the observer around Earth's axis, which is a signature of a nearby object. [1] [10]
Parameter | Epoch | Orbit type | Period (p) | Aphelion (Q) | Perihelion (q) | Semi-major axis (a) | Inclination (i) | Heliocentric eccentricity (e) | Geocentric eccentricity (e) [10] [lower-alpha 3] |
---|---|---|---|---|---|---|---|---|---|
Units | (years) | AU | (°) | ||||||
2020-May-31 [4] | Apollo | 1.056 | 1.0722 | 1.0020 | 1.0371 | 0.14061° | 0.03389 | 737 | |
2020-Dec-17 [2] | Atira | 0.980 | 0.9882 | 0.9847 | 0.9865 | 0.13842° | 0.00180 | 0.89934 |
In January and February 2036, it will again approach Earth with a geocentric eccentricity less than 1 since the relative velocities will be small, [10] but will not be within Earth's Hill sphere of 0.01 AU (1.5 million km). [4] [lower-alpha 4]
1998 KY26 is a nearly spherical sub-kilometer asteroid, classified as a near-Earth object of the Apollo group. It measures approximately 30 meters (100 feet) in diameter and is a fast rotator, having a rotational period of only 10.7 minutes. It was first observed on 2 June 1998, by the Spacewatch survey at Kitt Peak National Observatory during 6 days during which it passed 800,000 kilometers (half a million miles) away from Earth (a little more than twice the Earth–Moon distance).
A geocentric orbit, Earth-centered orbit, or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center. More than 16,291 objects previously launched have undergone orbital decay and entered Earth's atmosphere.
2006 RH120 is a tiny near-Earth asteroid and fast rotator with a diameter of approximately 2–3 meters that ordinarily orbits the Sun but makes close approaches to the Earth–Moon system around every twenty years, when it can temporarily enter Earth orbit through temporary satellite capture (TSC). Most recently, it was in Earth orbit from July 2006 to July 2007, during which time it was never more than 0.0116 AU (1.74 million km) from Earth. As a consequence of its temporary orbit around the Earth, it is currently the second smallest asteroid in the Solar System with a well-known orbit, after 2021 GM1. Until given a minor planet designation on 18 February 2008, the object was known as 6R10DB9, an internal identification number assigned by the Catalina Sky Survey.
1991 VG is a very small near-Earth object of the Apollo group, approximately 5–12 meters in diameter. It was first observed by American astronomer James Scotti on 6 November 1991, using the Spacewatch telescope on Kitt Peak National Observatory near Tucson, Arizona, in the United States. On 6 December 1991 it passed about 369635 km from the Moon. The asteroid then went unobserved from April 1992 until it was recovered by Paranal Observatory in May 2017. It was removed from the Sentry Risk Table on 1 June 2017.
2010 AL30 is a near-Earth asteroid that was discovered on 10 January 2010 at Grove Creek Observatory, Australia.
2011 MD is a bright micro-asteroid, classified as near-Earth object of the Apollo and Amor group, respectively. On 27 June 2011, at around 17:00 UTC, the object passed exceptionally close to Earth's surface at a distance of approximately 12,000 kilometers (7,500 mi), roughly the diameter of the Earth.
(471240) 2011 BT15, provisional designation 2011 BT15, is a stony, sub-kilometer sized asteroid and fast rotator, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group. It had been one of the objects with the highest impact threat on the Palermo Technical Impact Hazard Scale.
(192642) 1999 RD32, provisional designation: 1999 RD32, is an asteroid and suspected contact binary on an eccentric orbit, classified as a large near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 5 kilometers (3 miles) in diameter. It was discovered on 8 September 1999, at a magnitude of 18, by astronomers of the LINEAR program using its 1-meter telescope at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, United States. The asteroid is likely of carbonaceous composition and has a rotation period of 17.08 hours.
2014 RC is a sub-kilometer near-Earth object and Apollo asteroid. The exceptionally fast rotator passed within 0.000267 AU (39,900 km; 24,800 mi) (0.1 lunar distances) of Earth on 7 September 2014. The asteroid is approximately the diameter of the Chelyabinsk meteor, and passed almost as close to Earth as 367943 Duende (2012 DA14) did in 2013.
2015 TB145 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 650 meters (2,000 feet) in diameter. It safely passed 1.27 lunar distances from Earth on 31 October 2015 at 17:01 UTC, and passed by Earth again in November 2018.
469219 Kamoʻoalewa, provisionally designated 2016 HO3, is a very small asteroid, fast rotator and near-Earth object of the Apollo group, approximately 40–100 meters (130–330 feet) in diameter. At present it is a quasi-satellite of Earth, and currently the second-smallest, closest, and most stable known such quasi-satellite (after 2023 FW13). The asteroid was discovered by Pan-STARRS at Haleakala Observatory on 27 April 2016. It was named Kamoʻoalewa, a Hawaiian word that refers to an oscillating celestial object. The Earth-like orbit and lunar-like silicates may be a result of it being lunar ejecta.
(505657) 2014 SR339, provisional designation 2014 SR339, is a dark and elongated asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 970 meters (3,200 feet) in diameter. It was discovered on 30 September 2014, by NASA's Wide-field Infrared Survey Explorer telescope (WISE) in Earth's orbit. Closely observed at Goldstone and Arecibo in February 2018, it has a rotation period of 8.7 hours.
A temporary satellite is an object which has been captured by the gravitational field of a planet and thus has become the planet's natural satellite, but, unlike irregular moons of the larger outer planets of the Solar System, will eventually either leave its orbit around the planet or collide with the planet. The only observed examples are 2006 RH120, a temporary satellite of Earth for twelve months from July 2006 to July 2007, and 2020 CD3, which was discovered in 2020. Some defunct space probes or rockets have also been observed on temporary satellite orbits.
2020 CD3 (also 2020CD3 or CD3 for short) is a tiny near-Earth asteroid (or minimoon) that ordinarily orbits the Sun but makes close approaches to the Earth–Moon system, in which it can temporarily enter Earth orbit through temporary satellite capture (TSC). It was discovered at the Mount Lemmon Observatory by astronomers Theodore Pruyne and Kacper Wierzchoś on 15 February 2020, as part of the Mount Lemmon Survey or Catalina Sky Survey. The asteroid's discovery was announced by the Minor Planet Center on 25 February 2020, after subsequent observations confirmed that it was orbiting Earth.
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(231937) 2001 FO32 is a near-Earth asteroid classified as a potentially hazardous asteroid of the Apollo group. With an estimated diameter around 550 m (1,800 ft), it was discovered by the Lincoln Near-Earth Asteroid Research at Socorro, New Mexico on 23 March 2001. The asteroid safely passed by Earth on 21 March 2021 16:03 UTC from a closest approach distance of 0.0135 AU (2.02 million km; 1.25 million mi), or 5.25 lunar distances (LD). During the day before closest approach, 2001 FO32 reached a peak apparent magnitude of 11.7 and was visible to ground-based observers with telescope apertures of at least 20 cm (8 in). It is the largest and one of the fastest asteroids to approach Earth within 10 LD (3.8 million km; 2.4 million mi) in 2021.
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Spectroscopy on the surface of 2020 SO can also determine whether it has titanium dioxide - the paint material used on space rockets.