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Discovery [1] [2] | |
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Discovered by | R. H. McNaught |
Discovery site | Siding Spring Obs. |
Discovery date | 9 November 1991 |
Designations | |
1991 VH | |
NEO · Apollo · PHA [3] | |
Orbital characteristics [3] | |
Epoch 21 January 2022 (JD 2459600.5) | |
Uncertainty parameter 0 | |
Observation arc | 29.34 yr (10,717 days) |
Aphelion | 1.3014 AU |
Perihelion | 0.9732 AU |
1.1373 AU | |
Eccentricity | 0.1443 |
1.21 yr (443.02 days) | |
7.959° | |
0° 48m 45.357s / day | |
Inclination | 13.912° |
139.349° | |
206.940° | |
Known satellites | 1 |
Earth MOID | 0.02467 AU (3,691,000 km; 9.60 LD) |
Physical characteristics [4] | |
Dimensions | 1.30 × 1.25 × 1.18 km [5] |
Mean diameter | 1.18±0.18 km (primary) [5] |
Mass | (1.58±0.08)×1012 kg (system) [5] 1.4×1012 kg (primary) [lower-alpha 1] |
Mean density | 1.7±0.8 g/cm3 [5] |
2.6238±0.0001 h [6] [4] | |
0.17–0.18 [5] | |
Sk (SMASS) [3] V–R=0.38±0.04 [7] R–I=0.36±0.04 [7] | |
17.02±0.07 (H-G) [lower-alpha 2] 16.76 (assumed) [lower-alpha 3] | |
(35107) 1991 VH (provisional designation 1991 VH) is a binary near-Earth asteroid and potentially hazardous asteroid of the Apollo group. It was discovered on 9 November 1991, by Australian astronomer Robert McNaught at Siding Spring Observatory. This binary system is composed of a roughly-spheroidal primary body about one kilometre in diameter, and an elongated natural satellite less than half a kilometre in diameter. [5] The 1991 VH system is unusual for its dynamically excited state; the satellite has a tumbling, non-synchronous rotation that chaotically exchanges energy and angular momentum with its precessing, eccentric orbit. [11] [6] This asteroid system was one of the two targets of NASA's upcoming Janus Mayhem mission, [12] [13] until the delay of the rocket launch made both targets inaccessible. [14]
This minor planet was numbered by the Minor Planet Center on 27 February 2002. [15] It has not yet been named. [1]
1991 VH orbits the Sun at a distance of 0.98–1.30 AU once every 1.21 years (443 days). Its orbit has an eccentricity of 0.14 and an inclination of 14° with respect to the ecliptic. [3]
The asteroid has an Earth minimum orbital intersection distance of 0.0247 AU (3.70 million km; 2.30 million mi), which translates into approximately 9.6 lunar distances (LD). It has made multiple close approaches to Earth, with the closest being 0.0458 AU (6.85 million km; 4.26 million mi) or 17.8 LD on 15 August 2008. [3]
High-resolution radar imaging from Goldstone and Arecibo Observatory in 2008 show that the 1991 VH primary is a roughly-spheroidal object with an equatorial ridge, bearing resemblance to a spinning top. This shape is not unique to 1991 VH as it been observed in other near-Earth asteroids; most notably 3200 Phaethon, 66391 Moshup, 101955 Bennu, and 162173 Ryugu. [5] [16] A number of topographical features, including a 100 m (330 ft)-wide concavity, are present along the object's equatorial ridge. A bright linear feature casting a shadow at the object's mid- to high-latitudes was also seen in the 2008 radar images. [5]
Preliminary modeling of the primary's shape in radar images indicates dimensions of 1.30 km × 1.25 km × 1.18 km (0.81 mi × 0.78 mi × 0.73 mi), or a volume-equivalent diameter of 1.18 km (0.73 mi). [5] The geometric albedo for the primary is 0.17–0.18, considerably lower than infrared-based estimates of 0.30–0.40. [8] [4]
The total mass of the 1991 VH system is (1.58±0.08)×1012 kg, based on the orbital motion of the satellite. The mass ratio of the satellite to the primary is 0.086±0.018, corresponding to a primary mass of 1.4×1012 kg—approximately 12 times as massive as the satellite. [lower-alpha 1] Given the primary mass and diameter, its density is estimated to be about 1.7±0.8 g/cm3, indicative of a rubble pile internal structure. [5] [17]
In the SMASS taxonomy, 1991 VH is classified as a transitional Sk-type, which is an intermediary between the common stony S-type and the less frequent K-type asteroids. [3]
Photometric observations in 1997 determined a primary rotation period of 2.624 hours, with a light curve amplitude of 0.08±0.01 magnitudes ( U=3 ). [7] Later photometric observations from 2003–2020 corroborated this result down to a precision of ±0.0001 seconds. [4] [18]
![]() Radar images of S/2008 (35107) 1 by Arecibo Observatory on 12 August 2008 | |
Discovery [19] [20] | |
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Discovered by | P. Pravec M. Wolf L. Šarounová |
Discovery site | Ondřejov Obs. |
Discovery date | 27 February 1997 |
Designations | |
S/1997 (35107) 1 [3] | |
Orbital characteristics [5] | |
3.32±0.07 km | |
Eccentricity | 0.05±0.02 [6] [9] |
32.57±0.3 h (1.357±0.012 d) | |
Inclination | 148°±9° (wrt ecliptic) [3] [9] |
270°±30° [3] [9] | |
Physical characteristics | |
Dimensions | a/b = 1.33±0.10 [21] |
Mean diameter | 0.42±0.08 km [22] (Ds/Dp=0.40±0.02) [9] |
Mass | 1.4×1011 kg [lower-alpha 4] |
11–16 h (chaotic) [6] | |
17.2 (Δmag=0.2) [20] | |
S/2008 (35107) 1 is the secondary component and natural satellite of the 1991 VH system.
S/2008 (35107) 1 is among the first near-Earth asteroid satellites discovered, alongside those of (385186) 1994 AW1 and 3671 Dionysus. [7] It was discovered on 27 February 1997, by astronomers Petr Pravec, Marek Wolf, and Lenka Šarounová at Ondřejov Observatory. The satellite was detected through photometric observations of periodic dips in the system's brightness, caused by mutual eclipses and occultations of the components. [19] The discovery of the satellite was reported in a notice published by the International Astronomical Union on 29 March 1997, but was not officially confirmed until it was individually resolved in adaptive optics imaging by the Keck II telescope at Mauna Kea Observatory on 9 August 2008. The satellite was given the provisional designation S/2008 (35107) 1 on 19 September 2008. [20] [22]
As with many binary near-Earth asteroids, the 1991 VH system is thought to have formed through rotational fissioning of a progenitor body due to spin-up by the YORP effect. The resulting mass shed from the progenitor body coalesced in orbit to form the satellite. [17]
This asteroid system was the target of NASA's upcoming Janus Mayhem mission, which was planned to launch in 2022 alongside NASA's Psyche spacecraft, and to arrive in 2026. [12] [13] 1991 VH became impossible to reach for Janus when the launch of Psyche got delayed in May 2022. [14]
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.
1509 Esclangona, provisional designation 1938 YG, is a rare-type Hungaria asteroid and binary system from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It is named after French astronomer Ernest Esclangon.
(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.
6084 Bascom, provisional designation 1985 CT, is a binary Phocaea asteroid from the inner regions of the asteroid belt, approximately 6.3 kilometers in diameter. It was discovered on 12 February 1985, by American astronomer couple Carolyn and Eugene Shoemaker at Palomar Observatory in California. It is named after American geologist Florence Bascom. Its satellite measures approximately 2.3 kilometers and has an orbital period of 43.51 hours.
4029 Bridges, provisional designation 1982 KC1, is a stony asteroid and binary system from the middle regions of the asteroid belt, approximately 8 kilometers in diameter.
65803 Didymos is a sub-kilometer asteroid and binary system that is classified as a potentially hazardous asteroid and near-Earth object of the Apollo group. The asteroid was discovered in 1996 by the Spacewatch survey at Kitt Peak, and its small 160-meter minor-planet moon, named Dimorphos, was discovered in 2003. Due to its binary nature, the asteroid was then named Didymos, the Greek word for 'twin'.
1338 Duponta, provisional designation 1934 XA, is a stony Florian asteroid and synchronous binary system from the inner regions of the asteroid belt, approximately 7.8 kilometers in diameter.
9260 Edwardolson, provisional designation 1953 TA1, is a Florian binary asteroid from the inner regions of the asteroid belt, approximately 4.1 kilometers in diameter. It was discovered on 8 October 1953, by Indiana University during its Indiana Asteroid Program at Goethe Link Observatory in Brooklyn, Indiana, United States. It was named for American astronomer Edward Olson.
1453 Fennia, provisional designation 1938 ED1, is a stony Hungaria asteroid and synchronous binary system from the innermost regions of the asteroid belt, approximately 7 kilometers in diameter. Discovered by Yrjö Väisälä at the Turku Observatory in 1938, the asteroid was later named after the Nordic country of Finland. The system's minor-planet moon was discovered in 2007. It has a derived diameter of 1.95 kilometers and is orbiting its primary every 23.55 hours.
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.
5905 Johnson, provisional designation 1989 CJ1, is a Hungaria asteroid and synchronous binary system from the innermost regions of the asteroid belt, approximately 4 kilometers (2.5 miles) in diameter. It was discovered on 11 February 1989, by American astronomer Eleanor Helin at Palomar Observatory in California, United States. Its satellite measures approximately 1.6 km (1 mi) in diameter and orbits its primary every 21.8 hours. It was named after American astronomer and engineer Lindley N. Johnson.
5481 Kiuchi, provisional designation 1990 CH, is a bright binary Vestian asteroid from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 15 February 1990, by Japanese astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory in Hokkaidō, Japan, and named after their colleague Tsuruhiko Kiuchi. The V-type asteroid has a rotation period of 3.6 hours.
1830 Pogson, provisional designation 1968 HA, is a stony Florian asteroid and an asynchronous binary system from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 17 April 1968, by Swiss astronomer Paul Wild at the Zimmerwald Observatory near Bern, Switzerland. The S-type asteroid has a rotation period 2.6 of hours. It was named for English astronomer Norman Pogson. The discovery of its 2.5-kilometer sized companion was announced in May 2007.
2815 Soma, provisional designation 1982 RL, is a binary Florian asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 15 September 1982, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station in Flagstaff, Arizona, in the United States. It is named for the mechanical puzzle Soma cube.
5477 Holmes, provisional designation 1989 UH2, is a Hungaria asteroid and binary system from the innermost regions of the asteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered on 27 October 1989, by American astronomer Eleanor Helin at the Palomar Observatory in California. The presumed E-type asteroid is likely spherical in shape and has a short rotation period of 2.99 hours. It was named for American amateur astronomer Robert Holmes. The discovery of its 1-kilometer-sized minor-planet moon was announced in November 2005.
(175706) 1996 FG3 is a carbonaceous asteroid and binary system, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.7 kilometers (1.1 miles) in diameter. The primary has a spheroidal shape. Its minor-planet moon measures approximately 490 meters (1,600 feet) in diameter.
(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.
(66063) 1998 RO1 is a stony near-Earth object of the Aten group on a highly-eccentric orbit. The synchronous binary system measures approximately 800 meters (0.50 miles) in diameter. It was discovered by astronomers of the Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, on 14 September 1998.
(15700) 1987 QD is a Mars-crossing asteroid and a binary candidate from inside the innermost region of the asteroid belt, approximately 3 kilometers in diameter. It was discovered on 24 August 1987, by American astronomer Stephen Singer-Brewster at the Palomar Observatory in California. The likely spherical X-type asteroid has a rotation period of 3.1 hours. The suspected presence of a kilometer-sized minor-planet moon was announced in November 2000.