Discovery [1] | |
---|---|
Discovered by | K. Reinmuth |
Discovery site | Heidelberg Obs. |
Discovery date | 28 October 1937 |
Designations | |
(69230) Hermes | |
Pronunciation | /ˈhɜːrmiːz/ [2] |
Named after | Hermes (Greek mythology) [3] |
1937 UB | |
NEO · PHA · Apollo [1] [4] Mars- and Venus-crosser | |
Adjectives | Hermian, Hermean /ˈhɜːrmiən,hərˈmiːən/ |
Orbital characteristics [4] | |
Epoch 27 April 2019 (JD 2458600.5) | |
Uncertainty parameter 0 | |
Observation arc | 80.94 yr (29,565 d) |
Earliest precovery date | 25 October 1937 |
Aphelion | 2.6878 AU |
Perihelion | 0.6226 AU |
1.6552 AU | |
Eccentricity | 0.6239 |
2.13 yr (778 d) | |
73.583° | |
0° 27m 46.08s / day | |
Inclination | 6.0670° |
34.217° | |
92.746° | |
Known satellites | 1 [5] (P:13.892±0.006 h) [6] [7] (D: 0.54 km, [8] 0.56 km [9] ) |
Earth MOID | 0.0043 AU (1.6752 LD) |
Physical characteristics | |
0.8±0.1 km [6] 0.81 km(derived) [5] 0.85 km [7] [10] | |
Mean density | 1.6 g/cm3 (assumed) [5] |
13.894 h [11] [12] [lower-alpha 1] | |
0.25±0.12 [5] [11] 0.265±0.099 [6] | |
S [13] [lower-alpha 2] ·Sq [7] [14] | |
17.48 [6] 17.5 [1] [4] 17.55 [15] 17.57 [7] [11] [16] | |
69230 Hermes is a sub-kilometer sized asteroid and binary system on an eccentric orbit, [10] 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. [3] 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. [7] 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. [5]
Hermes was discovered by German astronomer Karl Reinmuth in images taken at Heidelberg Observatory on 28 October 1937. [1] Only four days of observations could be made before it became too faint to be seen in the telescopes of the day. [17] This was not enough to calculate an orbit, and Hermes became a lost asteroid. [17] It thus did not receive a number, but Reinmuth nevertheless named it after the Greek god Hermes. It was the third unnumbered but named asteroid, having only the provisional designation 1937 UB. The two others long lost were (1862) Apollo, discovered in 1932 and numbered in 1973, and (2101) Adonis, discovered in 1936 and numbered in 1977. [18]
On 15 October 2003, Brian A. Skiff of the LONEOS project made an asteroid observation that, when the orbit was calculated backwards in time (by Timothy B. Spahr, Steven Chesley and Paul Chodas), turned out to be a rediscovery of Hermes. It has been assigned sequential number 69230. Additional precovery observations were published by the Minor Planet Center, the earliest being found in images taken serendipitously by the MPG/ESO 2.2-m La Silla telescope on 16 September 2000. [1]
This minor planet was named after the Greek god Hermes, who is the messenger of the gods and son of Zeus and Maia (see also 5731 and 66). Recovered and numbered in late 2003, Hermes was originally named by the Astronomical Calculation Institute as early as 1937. [3] The official naming citation was published by the Minor Planet Center on 9 November 2003 ( M.P.C. 50255). [19]
Hermes is an Apollo asteroid, a subgroup of near-Earth asteroids that cross the orbit of Earth. It orbits the Sun at a distance of 0.6–2.7 AU once every 2 years and 2 months (778 days; semi-major axis of 1.66 AU). Its orbit has an eccentricity of 0.62 and an inclination of 6° with respect to the ecliptic. [4] Due to its eccentricity, Hermes is also a Mars- and Venus-crosser. Frequent close approaches to both Earth and Venus make it unusually challenging to forecast its orbit more than a century in advance, though there is no impact risk within that timeframe. [20]
The asteroid has an Earth minimum orbital intersection distance of 0.0041 AU (610,000 km) which translates into 1.6 LD. [4] On 30 October 1937, Hermes passed 0.00494 AU (739,000 km) from Earth, and on 26 April 1942, 0.0042415 AU (634,520 km) from Earth. [21] In retrospect it turned out that Hermes came even closer to the Earth in 1942 than in 1937, within 1.7 lunar distances; the second pass was unobserved at the height of the Second World War. [21] For decades, Hermes was known to have made the closest known approach of an asteroid to the Earth. Not until 1989 was a closer approach (by 4581 Asclepius) observed. At closest approach, Hermes was moving 5° per hour across the sky and reached 8th magnitude.
PHA | Date | Approach distance (lunar dist.) | Abs. mag ( H ) | Diameter (C) (m) | Ref (D) | ||
---|---|---|---|---|---|---|---|
Nomi- nal(B) | Mini- mum | Maxi- mum | |||||
(33342) 1998 WT24 | 1908-12-16 | 3.542 | 3.537 | 3.547 | 17.9 | 556–1795 | data |
(458732) 2011 MD5 | 1918-09-17 | 0.911 | 0.909 | 0.913 | 17.9 | 556–1795 | data |
(7482) 1994 PC1 | 1933-01-17 | 2.927 | 2.927 | 2.928 | 16.8 | 749–1357 | data |
69230 Hermes | 1937-10-30 | 1.926 | 1.926 | 1.927 | 17.5 | 668–2158 | data |
69230 Hermes | 1942-04-26 | 1.651 | 1.651 | 1.651 | 17.5 | 668–2158 | data |
(137108) 1999 AN10 | 1946-08-07 | 2.432 | 2.429 | 2.435 | 17.9 | 556–1795 | data |
(33342) 1998 WT24 | 1956-12-16 | 3.523 | 3.523 | 3.523 | 17.9 | 556–1795 | data |
(163243) 2002 FB3 | 1961-04-12 | 4.903 | 4.900 | 4.906 | 16.4 | 1669–1695 | data |
(192642) 1999 RD32 | 1969-08-27 | 3.627 | 3.625 | 3.630 | 16.3 | 1161–3750 | data |
(143651) 2003 QO104 | 1981-05-18 | 2.761 | 2.760 | 2.761 | 16.0 | 1333–4306 | data |
2017 CH1 | 1992-06-05 | 4.691 | 3.391 | 6.037 | 17.9 | 556–1795 | data |
(170086) 2002 XR14 | 1995-06-24 | 4.259 | 4.259 | 4.260 | 18.0 | 531–1714 | data |
(33342) 1998 WT24 | 2001-12-16 | 4.859 | 4.859 | 4.859 | 17.9 | 556–1795 | data |
4179 Toutatis | 2004-09-29 | 4.031 | 4.031 | 4.031 | 15.3 | 2440–2450 | data |
2014 JO25 | 2017-04-19 | 4.573 | 4.573 | 4.573 | 17.8 | 582–1879 | data |
(137108) 1999 AN10 | 2027-08-07 | 1.014 | 1.010 | 1.019 | 17.9 | 556–1795 | data |
(35396) 1997 XF11 | 2028-10-26 | 2.417 | 2.417 | 2.418 | 16.9 | 881–2845 | data |
(154276) 2002 SY50 | 2071-10-30 | 3.415 | 3.412 | 3.418 | 17.6 | 714–1406 | data |
(164121) 2003 YT1 | 2073-04-29 | 4.409 | 4.409 | 4.409 | 16.2 | 1167–2267 | data |
(385343) 2002 LV | 2076-08-04 | 4.184 | 4.183 | 4.185 | 16.6 | 1011–3266 | data |
(52768) 1998 OR2 | 2079-04-16 | 4.611 | 4.611 | 4.612 | 15.8 | 1462–4721 | data |
(33342) 1998 WT24 | 2099-12-18 | 4.919 | 4.919 | 4.919 | 17.9 | 556–1795 | data |
(85182) 1991 AQ | 2130-01-27 | 4.140 | 4.139 | 4.141 | 17.1 | 1100 | data |
314082 Dryope | 2186-07-16 | 3.709 | 2.996 | 4.786 | 17.5 | 668–2158 | data |
(137126) 1999 CF9 | 2192-08-21 | 4.970 | 4.967 | 4.973 | 18.0 | 531–1714 | data |
(290772) 2005 VC | 2198-05-05 | 1.951 | 1.791 | 2.134 | 17.6 | 638–2061 | data |
(A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18. (B) Nominal geocentric distance from the Earth's center to the object's center (Earth radius≈0.017 LD). (C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y. (D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD) (E) Color codes: unobserved at close approach observed during close approach upcoming approaches |
Hermes is a stony S-type asteroid, as reported by Andy Rivkin and Richard Binzel. [13] [lower-alpha 2] It has been characterized as a Sq-subtype using the SpeX instrument at NASA Infrared Telescope Facility. Sq-types transition to the Q-type asteroid. [14]
Three rotational lightcurves of Hermes were obtained from photometric observations in October 2003. Lightcurve analysis gave a well-defined rotation period between 13.892 and 13.894 hours with a brightness variation between and 0.06 and 0.08 magnitude, which indicates that the body has a nearly spherical shape ( U=3/3/3 ). [15] [11] [12] [lower-alpha 1]
Radar observations led by Jean-Luc Margot at Arecibo Observatory and Goldstone in October and November 2003 showed Hermes to be a binary asteroid. The primary and secondary components have nearly identical radii of 315 m (1,033 ft) and 280 m (920 ft), respectively, [9] and their orbital separation is only 1,200 metres, [10] much smaller than the Hill radius of 35 km. [8]
The two components are in double synchronous rotation (similar to the trans-Neptunian system Pluto and Charon). [9] Hermes is one of only four systems of that kind known in the near-Earth object population. The other three are 1994 CJ1 , (190166) 2005 UP156 , and 2017 YE5 . [22]
In the 1978 novel The Hermes Fall by John Baxter, the asteroid endangers the Earth in 1980. [23] It is not explicitly made clear as to whether or not the Hermes asteroid from The Hermes Fall is 69230 Hermes.
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.
4197 Morpheus, provisional designation 1982 TA, is a highly eccentric asteroid and near-Earth object of the Apollo group, approximately 3 kilometers in diameter. It was discovered on 11 October 1982, by American astronomers Eleanor Helin and Eugene Shoemaker at Palomar Observatory in California, United States. The asteroid was later named for Morpheus from Greek mythology.
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.
3309 Brorfelde, provisional designation 1982 BH, is a nearly spheroidal, binary Hungaria asteroid from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 28 January 1982, by Danish astronomers Kaare Jensen and Karl Augustesen at the Brorfelde Observatory near Holbæk, Denmark. It was named for the discovering observatory and the village where it is located.
4674 Pauling, provisional designation 1989 JC, is a spheroidal binary Hungaria asteroid from the innermost regions of the asteroid belt, approximately 4.5 kilometers in diameter. It was discovered by American astronomer Eleanor Helin at the U.S. Palomar Observatory, California, on 2 May 1989, and named after the American chemist and Nobel laureate Linus Pauling.
(9992) 1997 TG19 is a stony asteroid and eccentric Mars-crosser, approximately 4 kilometers in diameter. It was discovered on 8 October 1997, by Japanese astronomers Tetsuo Kagawa and Takeshi Urata at Gekko Observatory near Shizuoka, Japan.
(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.
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.
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.
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.
3102 Krok, provisional designation 1981 QA, is a rare-type asteroid and slow rotator, classified as a near-Earth object of the Amor group, that measures approximately 1.5 kilometers in diameter.
7336 Saunders, provisional designation 1989 RS1, is a stony asteroid and near-Earth object of the Amor group, approximately 0.5 kilometers in diameter.
4786 Tatianina, provisional designation 1985 PE2, is a bright background asteroid and synchronous binary system from the inner regions of the asteroid belt, approximately 3.4 kilometers (2.1 miles) in diameter. It was discovered on 13 August 1985, by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. It was named after Tatiana Somova, a friend of the discoverer. The E-/Xc-subtype has a short rotation period of 2.9 hours. Its sub-kilometer minor-planet moon was discovered on 20 March 2006 and announced the following month.
12923 Zephyr (prov. designation:1999 GK4) is a stony asteroid, classified as potentially hazardous asteroid and near-Earth object of the Apollo group, approximately 2 kilometers (1.2 miles) in diameter. It was discovered on 11 April 1999, by astronomers of the Lowell Observatory Near-Earth Object Search at Anderson Mesa Station near Flagstaff, Arizona. The asteroid was named after the deity Zephyrus from Greek mythology.
(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.
(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.