85 Io

Last updated

85 Io
85Io (Lightcurve Inversion).png
Lightcurve-based 3D-model of Io
Discovery
Discovered by C. H. F. Peters
Discovery date19 September 1865
Designations
(85) Io
Pronunciation /ˈ./ [1]
Named after
Io
A899 LA ·A899 UA
main-belt  ·(middle)
Eunomian interloper
Adjectives Ionian /ˈniən/
Orbital characteristics [2]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 151.35 yr (55,280 days)
Aphelion 3.1679 AU
Perihelion 2.1379 AU
2.6529 AU
Eccentricity 0.1941
4.32 yr (1,578 days)
83.678°
0° 13m 41.16s / day
Inclination 11.961°
203.12°
123.11°
Physical characteristics
Dimensions180 × 160 × 160 km [3] [4]
Mass (5.034 ± 0.999/1.406)×1018 kg [5]
Mean density
2.14 ± 0.425/0.598 g/cm3 [5] [lower-alpha 1]
0.2864 d (6.875 h) [2]
0.0666 ± 0.003 [2]
F C (Tholen) [2]
B (SMASSII) [2]
7.96 [2]

    85 Io is a carbonaceous asteroid in the central region of the asteroid belt, approximately 170 kilometers in diameter. It is an identified Eunomian interloper.

    Contents

    Discovery and naming

    It was discovered by C. H. F. Peters on 19 September 1865, and named after Io, a lover of Zeus in Greek mythology. Io is also the name of the volcanic satellite of Jupiter. With a two-digit number and a two-letter name, 85 Io has the shortest designation of all minor planets.

    Orbit and physical characteristics

    Io is a retrograde rotator, with its pole pointing towards one of ecliptic coordinates (β, λ) = (-45°, 105°) or (-15°, 295°) with a 10° uncertainty. [3] This gives an axial tilt of about 125° or 115°, respectively. Its shape is quite regular.[ citation needed ]

    In the SMASS classification, Io is a carbonaceous C-type asteroid, which means that it is probably a primitive body composed of carbonates. Like 141 Lumen it is an interloper that orbits within the Eunomia asteroid family but it is not related to the shattered parent body.[ citation needed ]

    An Ionian diameter of 178 kilometres was measured from an occultation of a star on 10 December 1995. [4] Another asteroid occultation of Io (magnitude 13.2) occurred on 12 March 2009, from the eastern United States, with the star 2UCAC 35694429 (magnitude 13.8). [6]

    Conjunction to sunstationary, then retrogradeOppositionMinimal distance (AE)Maximum brightness (mag)stationary, then prograde
    27. April 200431.October 200423. December 20041,92017 AE12,3 mag11. February 2005
    3.August 20059. January 20065. March 20062,14389 AE11,8 mag25. April 2006
    17.October 200626. April 20079.June 20071,38393 AE12,1 mag26.July 2007
    7. March 20086.October 200822.November 20081,61470 AE10,7 mag9. January 2009
    8. July 200917. December 200912. February 20102,19864 AE11,1 mag3. April 2010
    21. September 201015. March 201130. April 20111,68623 AE12,2 mag20.June 2011
    7. January 201231.August 201212.October 20121,28465 AE11,1 mag19.November 2012
    9.June 201325.November 201320. January 20142,13519 AE10,1 mag12. March 2014
    29.August 201410. February 20151. April 20151,95222 AE12,2 mag22.May 2015
    22.November 201530.June 201614.August 20161,16222 AE11,6 mag17.September 2016
    3.May 20173.November 201726. December 20171,95048 AE10,2 mag15. February 2018
    6.August 201813. January 20199. March 20192,12957 AE11,8 mag28. April 2019
    21.October 20192.May 202014.June 20201,34977 AE12,0 mag30.July 2020

    See also

    Notes

    1. Assuming a diameter of 165 ± 3 km.

    Related Research Articles

    <span class="mw-page-title-main">8 Flora</span> Large main-belt asteroid

    8 Flora is a large, bright main-belt asteroid. It is the innermost large asteroid: no asteroid closer to the Sun has a diameter above 25 kilometres, and not until 20-km 149 Medusa was discovered was an asteroid known to orbit at a closer mean distance. It is the seventh-brightest asteroid with a mean opposition magnitude of +8.7. Flora can reach a magnitude of +8.1 at a favorable opposition near perihelion, such as occurred in November 2020 when it was 0.88 AU from Earth.

    <span class="mw-page-title-main">42 Isis</span> Main-belt asteroid

    42 Isis is a large main-belt asteroid, measuring 100.2 km in diameter with a stony (S-type) composition. It was discovered by English astronomer N.R. Pogson on 23 May 1856 at Oxford, and was his first asteroid discovery. The asteroid's name was chosen by Manuel John Johnson, director of the Radcliffe Observatory in Oxford. Although Isis is the name of an Egyptian goddess, the name was chosen in homage to Pogson's astronomer daughter, (Elizabeth) Isis Pogson. In addition, the Isis is the stretch of the River Thames that runs through Oxford.

    <span class="mw-page-title-main">47 Aglaja</span> Main-belt asteroid

    47 Aglaja is a large, dark main belt asteroid. It was discovered by Robert Luther on 15 September 1857 from Düsseldorf. The name was chosen by the Philosophical Faculty of the University of Bonn and refers to Aglaea, one of the Charites in Greek mythology. It was rendered Aglaia in English sources into the early 20th century, as 'i' and 'j' are equivalent in Latin names and in the Latin rendering of Greek names.

    <span class="mw-page-title-main">78 Diana</span> Main-belt asteroid

    78 Diana is a large and dark main-belt asteroid. It was discovered by German astronomer Robert Luther on March 15, 1863, and named after Diana, Roman goddess of the hunt. The asteroid is orbiting the Sun at a distance of 2.620 AU with a period of 4.24 years and an eccentricity (ovalness) of 0.207. The orbital plane is tilted at an angle of 8.688° relative to the plane of the ecliptic. Its composition is carbonaceous and primitive.

    <span class="mw-page-title-main">107 Camilla</span> Asteroid with 2 moons

    107 Camilla is one of the largest asteroids from the outermost edge of the asteroid belt, approximately 250 kilometers in diameter. It is a member of the Sylvia family and located within the Cybele group. It was discovered on 17 November 1868, by English astronomer Norman Pogson at Madras Observatory, India, and named after Camilla, Queen of the Volsci in Roman mythology. The X-type asteroid is a rare trinary asteroid with two minor-planet moons discovered in 2001 and 2016, respectively. It is elongated in shape and has a short rotation period of 4.8 hours.

    <span class="mw-page-title-main">111 Ate</span> Main-belt asteroid

    111 Ate is a main-belt asteroid discovered by the German-American astronomer C. H. F. Peters on August 14, 1870, and named after Ate, the goddess of mischief and destruction in Greek mythology. In the Tholen classification system, it is categorized as a carbonaceous C-type asteroid, while the Bus asteroid taxonomy system lists it as an Ch asteroid.

    <span class="mw-page-title-main">135 Hertha</span> Main-belt asteroid

    135 Hertha is an asteroid from the inner region of the asteroid belt, approximately 77 kilometers in diameter. Discovered on 18 February 1874 by German–American astronomer Christian Peters at the Litchfield Observatory near Clinton, New York, it was named after the Teutonic and Scandinavian goddess of fertility, Hertha, also known as Nerthus. It orbits among the Nysa asteroid family, but its classification as a metallic M-type asteroid does not match the more common F-type asteroid for this family, suggesting that it may be an interloper. Spectroscopic analysis indicates the possible presence of hydrated silicates indicating that Hertha should possibly be reclassified from its present M-type to the proposed W-type.

    <span class="mw-page-title-main">146 Lucina</span> Main-belt asteroid

    146 Lucina is a main-belt asteroid that was discovered by Alphonse Borrelly on June 8, 1875, and named after Lucina, the Roman goddess of childbirth. It is large, dark and has a carbonaceous composition. The spectra of the asteroid displays evidence of aqueous alteration.

    <span class="mw-page-title-main">161 Athor</span> Main-belt asteroid

    161 Athor is an M-type Main belt asteroid that was discovered by James Craig Watson on April 19, 1876, at the Detroit Observatory and named after Hathor, an Egyptian fertility goddess. It is the namesake of a proposed Athor asteroid family, estimated to be ~3 billion years old.

    <span class="mw-page-title-main">164 Eva</span> Main-belt asteroid

    164 Eva is a main-belt asteroid that was discovered by the French brothers Paul Henry and Prosper Henry on July 12, 1876, in Paris. The reason the name Eva was chosen remains unknown, though Karl Ludwig Littrow suspected a "worldly origin". The orbital elements for 164 Eva were published in 1877 by American astronomer Winslow Upton. It is categorized as a C-type asteroid and is probably composed of primitive carbonaceous chondritic materials.

    <span class="mw-page-title-main">185 Eunike</span>

    185 Eunike is a dark and very large main-belt asteroid, with an approximate diameter of 157 kilometres. It has a primitive carbonaceous composition.

    <span class="mw-page-title-main">194 Prokne</span> Main-belt asteroid

    194 Prokne is a main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on March 21, 1879, in Clinton, New York, and named after Procne, the sister of Philomela in Greek mythology. Stellar occultations by Prokne have been observed twice, in 1984 from Italy and again in 1999 from Iowa.

    <span class="mw-page-title-main">200 Dynamene</span> Main-belt asteroid

    200 Dynamene is a large dark main-belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on July 27, 1879, in Clinton, New York. The name derives from Dynamene, one of the fifty Nereids in Greek mythology. Based upon its spectrum, 200 Dynamene is classified as a C-type asteroid, indicating that it probably has a primitive composition similar to the carbonaceous chondrite meteorites. The spectra of the asteroid displays evidence of aqueous alteration.

    <span class="mw-page-title-main">209 Dido</span> Main-belt asteroid

    209 Dido is a main-belt asteroid with a diameter of 179±1 km. It was discovered by C. H. F. Peters on October 22, 1879, in Clinton, New York and was named after the mythical Carthaginian queen Dido. This asteroid is orbiting the Sun at a distance of 3.15 AU with an eccentricity (ovalness) of 0.058 and a period of 5.59 yr. The orbital plane is tilted at an angle of 7.2° to the plane of the ecliptic.

    <span class="mw-page-title-main">238 Hypatia</span> Main-belt asteroid

    238 Hypatia is a large main-belt asteroid that was discovered by Russian astronomer Viktor Knorre on July 1, 1884, in Berlin. It was the third of his four asteroid discoveries. The name was given in honour of philosopher Hypatia of Alexandria. Based upon the spectrum, it is classified as a C-type asteroid and is probably composed of primitive carbonaceous material. Like many asteroids of this type, its surface is very dark in colour.

    <span class="mw-page-title-main">240 Vanadis</span> Main-belt asteroid

    240 Vanadis is a fairly large main-belt asteroid with a diameter of around 100 km. It was discovered by A. Borrelly on August 27, 1884, in Marseilles and was named after Freyja (Vanadis), the Norse fertility goddess. The asteroid is orbiting the Sun at a distance of 2.67 AU with a period of 4.35 yr and an orbital eccentricity of 0.206. The orbital plane is inclined at an angle of 2.10° to the plane of the ecliptic.

    <span class="mw-page-title-main">266 Aline</span> Main-belt asteroid

    266 Aline is a fairly large main belt asteroid that was discovered by Johann Palisa on 17 May 1887 in Vienna and is thought to have been named after the daughter of astronomer Edmund Weiss. It is a dark C-type asteroid and is probably composed of primitive carbonaceous material. 266 Aline is orbiting close to a 5:2 mean motion resonance with Jupiter, which is located at 2.824 AU.

    <span class="mw-page-title-main">381 Myrrha</span> Main-belt asteroid

    381 Myrrha is a main-belt asteroid that was discovered by the French astronomer Auguste Charlois on January 10, 1894, in Nice. It has been classified as a C-type asteroid and is most likely composed of carbonaceous material.

    735 Marghanna is a large carbonaceous background asteroid from the central regions of the asteroid belt, approximately 74 kilometers in diameter. It was discovered on 9 December 1912, by German astronomer Heinrich Vogt at the Heidelberg-Königstuhl State Observatory in southwest Germany. The dark C-type asteroid (Ch) has a rotation period of 20.6 hours and is rather regular in shape. It was named after Margarete Vogt and after Hanna, the mother and a relative of the discoverer, respectively.

    977 Philippa is a large background asteroid from the outer regions of the asteroid belt, approximately 65 kilometers in diameter. It was discovered on 6 April 1922, by Russian–French astronomer Benjamin Jekhowsky at the Algiers Observatory in Northern Africa. The C-type asteroid is likely irregular in shape and has a rotation period of 15.4 hours. It was named after French financier Baron Philippe de Rothschild (1902–1988).

    References

    1. Noah Webster (1884) A Practical Dictionary of the English Language
    2. 1 2 3 4 5 6 "JPL Small-Body Database Browser: 85 Io". Jet Propulsion Laboratory . Retrieved 1 November 2017.
    3. 1 2 Torppa, J.; et al. (2003). "Shapes and rotational properties of thirty asteroids from photometric data" (PDF). Icarus. 164 (2): 346. Bibcode:2003Icar..164..346T. doi:10.1016/s0019-1035(03)00146-5.
    4. 1 2 Erikson, A.; Berthier, J.; Denchev, P.V. (1999). "Photometric observations and modelling of the asteroid 85 Io in conjunction with data from an occultation event during the 1995-96 apparition". Planetary and Space Science. 47 (3–4): 327–330. Bibcode:1999P&SS...47..327E. doi:10.1016/S0032-0633(98)00128-7.
    5. 1 2 Fienga, A.; Avdellidou, C.; Hanuš, J. (February 2020). "Asteroid masses obtained with INPOP planetary ephemerides". Monthly Notices of the Royal Astronomical Society. 492 (1). doi: 10.1093/mnras/stz3407 .
    6. http://www.asteroidoccultation.com/2009_03/0312_85_20455.htm [ dead link ]