astro.wikisort.org - Asteroid

343158 Marsyas (prov. designated 2009 HC₈₂) is an asteroid on a retrograde orbit, classified as a large near-Earth object of the Apollo group. It may be an extinct comet or damocloid asteroid. The asteroid was discovered on 29 April 2009, by astronomers with the Catalina Sky Survey at the Catalina Station near Tucson, Arizona, in the United States.[1] Approximately 2 kilometers (1.2 miles) in diameter, it makes many close approaches to Earth, Venus, and Mars at a very high relative velocity. It was named after the satyr Marsyas from Greek mythology.[1][3]

343158 Marsyas

Discovery [1][2]
Discovered by	CSS
Discovery site	Catalina Stn.
Discovery date	29 April 2009
Designations
MPC designation	(343158) Marsyas
Named after	Marsyas [1][3] (Greek mythology)
Alternative designations	2009 HC82
Minor planet category	NEO · Apollo[1][4] Retrograde
Orbital characteristics [4]
Epoch 17 December 2020 (JD 2459200.5)
Uncertainty parameter 0
Observation arc	17.17 yr (6,270 d)
Aphelion	4.5656 AU
Perihelion	0.4886 AU
Semi-major axis	2.5271 AU
Eccentricity	0.8067
Orbital period (sidereal)	4.02 yr (1,467 d)
Mean anomaly	5.8661°
Mean motion	0° 14m 43.08s / day
Inclination	154.37°
Longitude of ascending node	295.40°
Argument of perihelion	298.88°
Earth MOID	0.1471 AU (57.2 LD)
TJupiter	1.3160
Physical characteristics
Mean diameter	1.7 km (est. at 0.22)[5] 3.5 km (est. at 0.05)[5]
Apparent magnitude	~20[2]
Absolute magnitude (H)	16.27[1][4]

Classification and orbit

Marsyas was initially listed as a potentially hazardous asteroid.[2] It was removed from the Sentry Risk Table on 6 May 2009.[6] It orbits the Sun at a distance of 0.49–4.6 AU once every 4.02 years (1,467 days; semi-major axis of 2.53 AU). Its orbit has an eccentricity of 0.81 and an inclination of 154° with respect to the ecliptic.[4]

Retrograde

Marsyas has a retrograde orbit and thus orbits the Sun in the opposite direction of other objects. Therefore, close approaches to this object can have very high relative velocities. As of 2012^[update], it had the highest relative velocity to Earth of objects that come within 0.5 AU of Earth.[7]

Close approaches

On 11 November 2024, Marsyas will pass about 0.485 AU (72,600,000 km; 45,100,000 mi) from Earth, but with a record high relative velocity of about 283,000 km/h (78.66 km/s).[8] Both Halley's Comet (254,000 km/h)[9] and 55P/Tempel-Tuttle (252,800 km/h)[10] have slightly lower relative velocities to Earth. Note however that when the asteroid is one astronomical unit from the sun (as it would be if it ever hit the earth), its relative speed will be less. On 2 February 2053, Marsyas will pass about 0.08 AU from Venus.[8] On 22 October 2060, it may pass about 0.004 AU (600,000 km; 370,000 mi) from Mars.[8]

Possible damocloid

The multiple planet crossing and retrograde orbit suggests that this object may be an extinct comet or damocloid asteroid similar to 5335 Damocles, 2008 KV42, and 20461 Dioretsa.[11]

Diameter

Based on a generic magnitude-to-diameter conversion, Marsyas measures approximately 1.7 to 3.5 kilometers in diameter, for an absolute magnitude of 16.2 and an assumed albedo between 0.22 and 0.05. Since the true albedo is unknown and it has an absolute magnitude (H) of 16.1,[4] it is about 1.6 to 3.6 km in diameter.[5]

Naming

On 14 May 2021, the object was named by the Working Group Small Body Nomenclature (WGSBN),[3] after Marsyas, a Phrygian satyr from Greek mythology, who dared to challenge Apollo in a musical contest. Marsyas lost and he was flayed alive in a cave near Celaenae for his hubris to challenge a god. As with the mythological account, the unusual retrograde orbit of asteroid Marsyas is opposed to most bodies in the Solar System, including 1862 Apollo.[1]

References

External links

• 2009 news images at HohmannTransfer.com
• List Of Apollo Minor Planets (by designation), Minor Planet Center
• 343158 Marsyas at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• 343158 Marsyas at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• 343158 Marsyas at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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