(93) Minerva
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Asteroid (93) Minerva |
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|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | Middle main belt |
| Asteroid family | Gefion family |
| Major semi-axis | 2.7553 AU |
| eccentricity | 0.1391 |
| Perihelion - aphelion | 2.3722 AU - 3.1385 AU |
| Inclination of the orbit plane | 8.558 ° |
| Length of the ascending node | 4.054 ° |
| Argument of the periapsis | 274.643 ° |
| Time of passage of the perihelion | October 29, 2017 |
| Sidereal period | 4 a 210 d 13.2 h |
| Mean orbital velocity | 0.0179 km / s |
| Physical Properties | |
| Medium diameter | 154.2 ± 1.3 km |
| Dimensions | 3.35 x 10 18 kg |
| Albedo | 0.056 ± 0.008 |
| Medium density | 1.9 g / cm³ |
| Rotation period | 5 h 58 min 55.2 s |
| Absolute brightness | 7.8 likes |
| Spectral class | C. |
| history | |
| Explorer | James C. Watson |
| Date of discovery | August 24, 1867 |
| Another name | 1949 QN 2 , 1902 DA |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. | |
(93) Minerva is an asteroid that moves in the middle of the main asteroid belt . With a mean diameter of 154 km, Minerva is one of the largest asteroids in the main belt. Minerva has two moons : Aegis and Gorgoneion , each 3.2 km in diameter.
Discovery and naming
Minerva was discovered on August 24, 1867 by the American astronomer James Craig Watson in Ann Arbor , Michigan ( USA ). The asteroid was his second discovery in the asteroid belt and was given the provisional designations 1902 DA and 1949 QN 2 .
The asteroid was named after Minerva , a moon goddess from Roman mythology , the equivalent of Athena , the goddess of wisdom from Greek mythology . In ancient Rome , Minerva belonged to the Capitoline Triassic , along with Jupiter and Juno , the three most important city deities who were worshiped on the Capitol . Her temple once stood in the middle of the Aventine Hill .
In total, the asteroid has been observed through several earth-based telescopes, a total of 1,836 times in 147 years. (As of Sept. 2017)
Track properties
Orbit
Minerva orbits the Sun in a prograde , elliptical orbit between 354,870,000 km (2.37 AU ) and 469,500,000 km (3.14 AU) from its center. The orbital eccentricity is 0.139, the web is about 8.5 ° relative to the ecliptic inclined . Its orbit is therefore in the middle asteroid belt .
The orbit period of Minerva is 4.57 years.
Minerva is an interloper in the Gefion family, which comprises a good 2500 asteroids, a group of asteroids with similar orbits named after (1272) Gefion . In contrast to Minerva, these usually belong to the S-type asteroids. This group used to be known as the Minerva family .
rotation
Minerva rotates once on its axis every 5 hours and 59 minutes. From this it follows that the asteroid performs 6,702.3 self- rotations ("days") in a Minerva year .
Physical Properties
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size
The most precise determination of the diameter ( geometric mean ) by Minerva is 154.155 km. While the main bodies of the multiple systems in the asteroid main belt mostly have elongated shapes, previous observations indicate an unusually round body;
Assuming a mean diameter of 154 km, the surface area is around 74,700 km 2 , which is roughly between the areas of Ireland and the Czech Republic .
Provisions of the diameter for Minerva
| year | Dimensions km | source |
|---|---|---|
| 1982 | 170.8 ± 1.4 | Millis et al. |
| 2001 | 141.55 ± 4 | IRAS |
| 2005 | 146.0 ± 5 | Dunham et al. |
| 2012 | 154.155 ± 1.298 | Masiero et al. |
The most precise determination is marked in bold .
internal structure
Minerva belongs to the C-type asteroids (according to another classification: CU). The comparatively high mean density of 1.9 g / cm 3 - C-type asteroids mostly have densities of 0.8 - 1.3 g / cm 3 - is an indication of a different composition of the dry, carbon-rich chondrites is similar. Spectroscopic analyzes hold open the possibility that Minerva, like the dwarf planet Ceres , could belong to the G-type asteroids. The asteroid has a dark surface with an albedo of 0.05; the surface color is therefore darker than coal.
Assuming a composition similar to that of the chondrite meteorites found on earth, it is not a compact body, but a rubble pile , an accumulation of dust and rocks with cavities. The porosity is estimated to be over 30%.
The mass of Minerva could so far be calculated to be 3.35 ∙ 10 18 kg. The absolute brightness is given as 8.0 mag.
The mean surface temperature is around 168 K (−105 ° C).
The Minerva Triple System
On August 16, 2009, two companions of Minerva were discovered by a team led by Franck Marchis using the adaptive optics of the Keck Telescope II . Both objects orbit the asteroid at regular intervals on almost circular orbits (eccentricities less than 0.05); the orbits are practically perpendicular to Minerva's equator due to the inclination of the orbit of around 90 °. The two moons were officially named Gorgoneion and Aegis by the International Astronomical Union (IAU) in December 2013 .
The inner moon Gorgoneion, initially referred to as S / 2009 (93) 2 , has a diameter of around 3 km and orbits Minerva at a distance of 375 km in 26.8 hours. Due to the orbit inclination of just over 90 °, Gorgoneion's slightly more eccentric orbit is slightly retrograde .
The outer moon Aegis, initially referred to as S / 2009 (93) 1 , has a diameter of around 4 km and orbits Minerva at a distance of around 624 km in 57.7 hours. Since the inclination of the orbit is still just under 90 °, Aegis' orbit is just one of the prograde orbits.
Minerva is after (87) Sylvia , (45) Eugenia , (3749) Balam , and (216) Cleopatra the fifth discovered multiple asteroid system in the main belt. Apart from the dwarf planets Pluto and Haumea - which also have an asteroid number - it is the eighth known asteroid after Sylvia, Eugenia, (47171) Lempo , (153591) 2001 SN 263 , Balam, Cleopatra and (136617) 1994 CC –Multiple system in the solar system.
The Minerva system at a glance:
| Components | Physical parameters | Path parameters | discovery | |||||
|---|---|---|---|---|---|---|---|---|
| Surname | Throughput diameter (km) |
Relative size % |
Mass (kg) |
Major semi-axis (km) |
Orbital time (d) |
eccentricity |
Inclination to Sylvia's equator |
Date of discovery Date of publication |
| (93) Minerva | 141.6 | 100.00 | 3.3 · 10 18 | - | - | - | - | August 24, 1867 1867 |
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Gorgoneion (Minerva II) |
3.2 | 2.1 | ? | 375.0 | 1.1147 | 0.05 | 91.4 | August 16, 2009 August 31, 2009 |
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Aegis (Minerva I) |
3.6 | 2.3 | ? | 623.5 | 2.4060 | 0.00 | 89.0 | August 16, 2009 August 31, 2009 |
See also
Web links
Individual evidence
- ^ Discovery Circumstances: Numbered Minor Planets. The international Astronomical Union - Minor Planet Center, accessed August 5, 2020 .
- ↑ MPC: (93) Minerva = 1902 DA = 1949 QN2. Retrieved September 6, 2017 .
- ↑ JPL: (93) Minerva at the JPL. Retrieved September 6, 2017 .
- ↑ D. Nesvorny, M. Broz, V. Carruba Identification and Dynamical Properties of Asteroid Families , 2014, arXiv: 1502.01628
- ^ RL Millis et al .: The occultation of AG + 29 ° 398 by 93 Minerva (1985). Retrieved September 6, 2017 .
- ↑ Yu Jiang et al .: Dynamical configurations of celestial systems comprised of multiple irregular bodies (2016). Retrieved September 6, 2017 .
- ↑ David W. Dunham et al .: Observed minor planet occultations events (2005). Retrieved September 6, 2017 .
- ^ Joseph R. Masiero et al .: Preliminary Analysis of WISE / NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids . 2012, bibcode : 2014ApJ ... 791..121M .
- ^ Franck Marchis et al .: Is the triple asteroid Minerva a baby-Ceres? (2011). Retrieved September 6, 2017 .