2011 MM4, provisional designation: 2011 MM4, is a sizable centaur and retrograde damocloid from the outer Solar System, approximately 64 kilometers (40 miles) in diameter. It was discovered on 24 June 2011, by astronomers with the Pan-STARRS 1 at the Haleakala Obs. in Hawaii.[1][3]
Discovery[1] | |
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Discovered by | Pan-STARRS 1 |
Discovery site | Haleakala Obs. |
Discovery date | 24 June 2011 |
Designations | |
MPC designation | 2011 MM4 |
Alternative designations | 2011 MM4 |
Minor planet category | centaur[2][3][4] · damocloid distant[1] |
Orbital characteristics[2] | |
Epoch 23 March 2018 (JD 2458200.5) | |
Uncertainty parameter 0 | |
Observation arc | 6.99 yr (2,552 d) |
Aphelion | 31.121 AU |
Perihelion | 11.138 AU |
Semi-major axis | 21.129 AU |
Eccentricity | 0.4729 |
Orbital period (sidereal) | 97.12 yr (35,473 d) |
Mean anomaly | 49.176° |
Mean motion | 0° 0m 36.36s / day |
Inclination | 100.48° |
Longitude of ascending node | 282.45° |
Argument of perihelion | 6.86° |
TJupiter | −0.4 |
Physical characteristics | |
Mean diameter | 64 km[3][5] |
Geometric albedo | 0.083[3][5] |
Absolute magnitude (H) | 9.5[1][2] |
2011 MM4 orbits the Sun at a distance of 11.1–31.2 AU once every 97 years and 2 months (35,473 days; semi-major axis of 21.13 AU). Its orbit has an eccentricity of 0.47 and an inclination of 100° with respect to the ecliptic.[2] The body's observation arc begins at Pan-STARRS in June 2010.[1]
2011 MM4 is a member of the centaurs, a population of inward-moving bodies transiting from the Kuiper belt to the group of Jupiter-family comets. Orbiting mainly between Jupiter and Neptune, they typically have a semi-major axis of 5.5 to 30.1 AU. Centaurs are cometary-like bodies with an eccentric orbit. Their short dynamical lifetime is due to the perturbing forces exerted on them by the outer planets of the Solar System.[6]
The object is on a retrograde orbit as it has an inclination of more than 90°.[2][7] There are only about a hundred known retrograde minor planets out of nearly 800,000 observed bodies, and, together with 2013 LU28 and 2008 YB3, it is among the largest such objects.[7] The object also meets the orbital definition for being a damocloid. This is a small group of cometary-like objects without a coma or tail and a Tisserand's parameter with respect to Jupiter of less than 2 besides a retrograde orbit.
This minor planet has no number yet.
According to the survey of centaurs and scattered-disk objects carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 2011 MM4 measures 64 kilometers in diameter and its surface has an albedo of 0.083,[5] which makes it too small to be considered as a dwarf-planet candidate.
As of 2021[update], no rotational lightcurve of has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2][8]
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