![]() Radar image of 2001 SN263 and its two satellites imaged by the Arecibo Observatory in 2008 | |
Discovery [1] | |
---|---|
Discovered by | LINEAR |
Discovery site | Lincoln Lab's ETS |
Discovery date | 20 September 2001 |
Designations | |
(153591) 2001 SN263 | |
2001 SN263 | |
NEO · Amor [1] [2] | |
Orbital characteristics [2] | |
Epoch 4 September 2017 (JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 25.18 yr (9,198 days) |
Aphelion | 2.9368 AU |
Perihelion | 1.0363 AU |
1.9865 AU | |
Eccentricity | 0.4783 |
2.80 yr (1,023 days) | |
148.57° | |
0° 21m 7.2s / day | |
Inclination | 6.6853° |
325.83° | |
172.86° | |
Known satellites | 2 [3] |
Earth MOID | 0.0520 AU ·20.3 LD |
Physical characteristics | |
Mean diameter | 2 km [3] 2.5±0.3 km [4] 2.6 km [5] 2.63±0.40 km [6] |
Mass | (917.5±2.2)×1010 kg [7] |
Mean density | 1.1±0.2 g/cm3 [4] |
3.20±0.01 h [8] 3.423±0.001 h [lower-alpha 1] 3.42510±0.00007 h [9] 3.4256±0.0002 h [4] | |
0.048±0.015 [6] | |
C [8] · B [lower-alpha 2] | |
16.81 [10] ·16.9 [2] | |
(153591) 2001 SN263 is a carbonaceous trinary [3] asteroid, classified as near-Earth object and former potentially hazardous asteroid of the Amor group, approximately 2.6 kilometers (1.6 miles) in diameter. It was discovered by the Lincoln Near-Earth Asteroid Research project at Lincoln Lab's Experimental Test Site in Socorro, New Mexico, on 20 September 2001. [1] The two synchronous minor-planet moons measure approximately 770 and 430 meters and have an orbital period of 16.46 and 150 hours, respectively. [4] [10]
This minor planet was numbered by the Minor Planet Center on 2 April 2007. [11] As of 2018, the primary and its moons have not been named. [1] In the scientific literature, the components of the trinary system are generically referred to as Alpha, Beta and Gamma, but these labels are not recognized by the IAU. [5] [4]
2001 SN263, the primary object of this trinary system, is an unusual carbonaceous near-Earth asteroid of a C- or somewhat brighter B-type. [8] [lower-alpha 2] It orbits the Sun at a distance of 1.0–2.9 AU once every 2 years and 10 months (1,023 days). Its orbit has an eccentricity of 0.48 and an inclination of 7° with respect to the ecliptic. [2] A first precovery was taken at Palomar Observatory during the Digitized Sky Survey in 1990, extending the body's observation arc by 11 years prior to its official discovery observation at Socorro. [1]
It has an Earth minimum orbital intersection distance (MOID) of 0.0520 AU (7,780,000 km), which translates into 20.3 lunar distances. [2] With an Earth MOID above 0.05 AU, 2001 SN263 is no longer a potentially hazardous asteroid, but it was classified as such by the MPC until early 2017. [1] [12]
Radar observations show that it measures 2.5 kilometers in diameter. [4] Its surface has a low albedo of 0.048. [6] Rotational lightcurves obtained from photometric observations gave a rotation period of 3.423 hours (best result) with a brightness variation between 0.13 and 0.27 magnitude ( U=2/3/3 ). [8] [9] [lower-alpha 1] Radar observations gave a concurring period of 3.4256 hours, and subsequent modeling of both radiometric and photometric observations gave a spin axis of (309.0°, −80.0°) in ecliptic coordinates (λ, β). [4]
In 2008, scientists using the planetary radar at Arecibo Observatory discovered that the object is orbited by two satellites, when the triple asteroid made a close approach to Earth of 0.066 AU (nearly 10 million kilometers). The largest body (preliminarily called Alpha) is spheroid in shape, with principal axes of 2.8±0.1 km, 2.7±0.1 km, and 2.9±0.3 km, with an effective diameter of 2.5±0.3 km and a density of 1.1±0.2 g/cm3. The satellites, named Beta and Gamma, are several times smaller in size. Beta is 0.77±0.12 km in diameter and Gamma0.43±0.14 km. [4]
The only other unambiguously identified triple asteroids in the near-Earth population are (136617) 1994 CC, which was discovered to be a triple system in 2009, and 3122 Florence, which was found to be a triple system in September 2017. [13]
The orbital properties of the satellites are listed in this table. [7] The orbital planes of both satellites are inclined relative to each other; the relative inclination is about 14 degrees. Such a large inclination is suggestive of past evolutionary events (e.g. close encounter with a terrestrial planet, mean-motion-resonance crossing) that may have excited their orbits from a coplanar configuration to an inclined state.
Name | Mass (est.) | Semi-major axis | Orbital period | Eccentricity |
---|---|---|---|---|
Gamma (inner) | 10×1010 kg | 3.8 km | 0.686 days | 0.016 |
Beta (outer) | 24×1010 kg | 16.6 km | 6.225 days | 0.015 |
This triple asteroid system is the target for the planned ASTER mission scheduled for launch in 2025 by the Brazilian Space Agency. [14]
1620 Geographos is a highly elongated, stony asteroid, near-Earth object and potentially hazardous asteroid of the Apollo group, with a mean-diameter of approximately 2.5 km (1.6 mi). It was discovered on 14 September 1951, by astronomers Albert George Wilson and Rudolph Minkowski at the Palomar Observatory in California, United States. The asteroid was named in honor of the National Geographic Society.
2063 Bacchus, provisional designation 1977 HB, is a stony asteroid and near-Earth object of the Apollo group, approximately 1 kilometer in diameter. The contact binary was discovered on 24 April 1977, by American astronomer Charles Kowal at the Palomar Observatory in California, United States. It was named after Bacchus from Roman mythology.
1036 Ganymed, provisional designation 1924 TD, is a stony asteroid on a highly eccentric orbit, classified as a near-Earth object of the Amor group. It was discovered by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg on 23 October 1924, and named after Ganymede from Greek mythology. With a diameter of approximately 35 kilometers, Ganymed is the largest of all near-Earth objects but does not cross Earth's orbit. The S-type asteroid has a rotation period of 10.3 hours. In October 2024, it is predicted to approach Earth at a distance of 56,000,000 km; 35,000,000 mi (0.374097 AU).
66391 Moshup, provisional designation 1999 KW4, is a binary asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Aten group, approximately 1.3 kilometers in diameter. It was discovered on 20 May 1999, by Lincoln Near-Earth Asteroid Research (LINEAR) at the Lincoln Laboratory's Experimental Test Site in Socorro, New Mexico, United States. It is a Mercury-crosser that comes extremely close to the Sun at a perihelion of 0.2 AU.
69230 Hermes is a sub-kilometer sized asteroid and binary system on an eccentric orbit, classified as a potentially hazardous asteroid and near-Earth object of the Apollo group, that passed Earth at approximately twice the distance of the Moon on 30 October 1937. The asteroid was named after Hermes from Greek mythology. It is noted for having been the last remaining named lost asteroid, rediscovered in 2003. The S-type asteroid has a rotation period of 13.9 hours. Its synchronous companion was discovered in 2003. The primary and secondary are similar in size; they measure approximately 810 meters (2,700 ft) and 540 meters (1,800 ft) in diameter, respectively.
3352 McAuliffe, provisional designation 1981 CW, is a rare-type asteroid and suspected binary system, classified as near-Earth object of the Amor group, approximately 2 kilometers in diameter. It was discovered on 6 February 1981, by American astronomer Norman Thomas at Lowell's Anderson Mesa Station near Flagstaff, Arizona, United States.
2100 Ra-Shalom is an asteroid and near-Earth object of the Aten group on an eccentric orbit in the inner Solar System. It was discovered on 10 September 1978, by American astronomer Eleanor Helin at the Palomar Observatory, California, who named it in commemoration of the Camp David Peace Accords. The C-type asteroid has a rotation period of 19.8 hours and measures approximately 2.7 kilometers in diameter.
1627 Ivar is an elongated stony asteroid and near-Earth object of the Amor group, approximately 15×6×6 km. It was discovered on 25 September 1929, by Danish astronomer Ejnar Hertzsprung at Leiden Southern Station, annex to the Johannesburg Observatory in South Africa. It was named after Ivar Hertzsprung, brother of the discoverer. 1627 Ivar was the first asteroid to be imaged by radar, in July 1985 by the Arecibo Observatory.
(185851) 2000 DP107 is a sub-kilometer sized asteroid, classified as potentially hazardous asteroid and near-Earth object of the Apollo group that is notable because it provided evidence for binary asteroids in the near-Earth population. The PROCYON probe developed by JAXA and the University of Tokyo was intended to flyby this asteroid before its ion thruster failed and could not be restarted.
3122 Florence is a stony trinary asteroid of the Amor group. It is classified as a near-Earth object and potentially hazardous asteroid. It measures approximately 5 kilometers in diameter. It orbits the Sun at a distance of 1.0–2.5 AU once every 2 years and 4 months ; the orbit has an eccentricity of 0.42 and an inclination of 22° with respect to the ecliptic. Florence has two moons.
5143 Heracles(provisional designation 1991 VL) is a highly eccentric, rare-type asteroid and synchronous binary system, classified as near-Earth object of the Apollo group, approximately 4.8 kilometers in diameter. The asteroid was discovered on 7 November 1991, by American astronomer Carolyn Shoemaker at Palomar Observatory in California, United States. It is named for the Greek divine hero Heracles. It has an Earth minimum orbit intersection distance of 0.058 AU (8.7 million km) and is associated with the Beta Taurids daytime meteor shower.
7088 Ishtar, provisional designation 1992 AA, is a synchronous binary asteroid and near-Earth object from the Amor group, approximately 1.3 kilometers in diameter. It was discovered on 1 January 1992, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California. The relatively bright asteroid with an unknown spectral type has a rotation period of 2.7 hours. In December 2005, a 330-meter sized satellite was discovered, orbiting its primary every 20.65 hours.
(450894) 2008 BT18 is a sub-kilometer asteroid and synchronous binary system, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It was discovered on 31 January 2008, by the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, United States. The eccentric asteroid measures approximately 600 meters in diameter and has a composition of a basaltic achondrite.
(136617) 1994 CC is a sub-kilometer trinary asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group.
(31345) 1998 PG is an eccentric, stony asteroid and binary system, classified as near-Earth object of the Amor group of asteroids, approximately 900 meters in diameter. It minor-planet moon, S/2001 (31345) 1, has an estimated diameter of 270 meters.
(436724) 2011 UW158, provisionally known as 2011 UW158, is a stony, walnut-shaped asteroid and fast rotator, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 300 meters in diameter. It was discovered on 25 October 2011, by Pan-STARRS at Haleakala Observatory on the island of Maui, Hawaii, in the United States.
(162421) 2000 ET70 is a dark, elongated and oblate asteroid, classified as near-Earth object and potentially hazardous asteroid of the Aten group, approximately 2.2 kilometers in diameter. It was discovered on 8 March 2000, by astronomers of the Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico. The body has a notably low albedo, and its shape resembles that of a "clenched fist".
(52768) 1998 OR2 (provisional designation 1998 OR2) is an asteroid on an eccentric orbit, classified as a near-Earth object and potentially hazardous asteroid of the Amor group, with a diameter of 2 kilometers (1.2 mi). It was discovered on 24 July 1998, by astronomers of the Near-Earth Asteroid Tracking (NEAT) program at the Haleakala Observatory, Hawaii. It is one of the brightest and therefore largest potentially hazardous asteroids known to exist. With an observation arc of 35 years, the asteroid has a well-determined orbit, and its trajectory is well known through the year 2197. The asteroid's orbit is only potentially hazardous on a time scale of thousands of years.
(143651) 2003 QO104, provisional designation 2003 QO104, is a stony asteroid, slow rotator and suspected tumbler on a highly eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Amor and Apollo group, respectively. It was discovered on 31 August 2003, by astronomers of the Near-Earth Asteroid Tracking program at the Haleakala Observatory in Hawaii, United States. The Q-type asteroid has a rotation period of 114.4 hours and possibly an elongated shape. It measures approximately 2.3 kilometers (1.4 miles) in diameter and belongs the largest potentially hazardous asteroids known to exist.
(164121) 2003 YT1, provisional designation 2003 YT1, is a bright asteroid and synchronous binary system on a highly eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 2 kilometers (1.2 miles) in diameter. It was discovered on 18 December 2003, by astronomers with the Catalina Sky Survey at the Catalina Station near Tucson, Arizona, in the United States. The V-type asteroid has a short rotation period of 2.3 hours. Its 210-meter sized minor-planet moon was discovered at Arecibo Observatory in May 2004.