Massalia family
The Massalia family (adj. Massalian;
Characteristics
This is a definite cratering family consisting of
The family is fairly young, estimated to have been created by an impact 100 to 200 million years ago. It has a distinctly two-lobed appearance in proper a--e space, with one lobe centered at semi-major axes of 2.38 AU, the other at about 2.43 AU, with the parent body Massalia itself located in between. The bodies in the lobes tend to be smaller on average than those in the central region. It has been shown that this structure is likely caused by slow drift of the semi-major axis caused by the Yarkovsky and YORP effects. Details of the lobes were used to calculate the age of the family.[2]
A strong 1:2 orbital resonance with Mars crosses the family at 2.42 AU, and appears responsible for some "leakage" of family members away from the area into higher inclination orbits.[2]
The Massalia family or a recent minor collision within it may be the source for the prominent α dust band, the other candidate being a recent collision within the Themis family.[2][3]
Location and size
The Massalian asteroids are located at very low inclinations, straddling the 1:2 resonances with Mars.
A
ap |
ep |
ip
| |
---|---|---|---|
min | 2.37 AU | 0.143 | 1.2° |
max | 2.45 AU | 0.175* | 1.75° |
- * The Zappalà core members only reach e=0.170 but inspection of more modern proper elements reveals that the family extends at least to e=0.175
At the present epoch, the range of osculating orbital elements of these core members is
a |
e |
i
| |
---|---|---|---|
min | 2.37 AU | 0.124 | 0.4° |
max | 2.45 AU | 0.211 | 2.35° |
The analysis by Zappalà found 42 core members in 1995,[4] while a HCM-analysis by Nesvorný in 2014 yielded 6,424 member asteroids based on the proper elements of a catalog of 398,000 bodies.[1]: 23
List
Name/designation | Number | Proper semimajor axis (AU) | Proper inclination (degrees) | Proper eccentricity | Diameter (km) | Group |
---|---|---|---|---|---|---|
Massalia | 20 | 2.409 | 1.421 | 0.162 | 150 (measured) | Primary member |
Muchachos |
2946 | 2.455 | 1.417 | 0.166 | 9 (estimated) | Interloper |
Puccini |
4579 | 2.400 | 1.392 | 0.163 | 8 (estimated) | Core member |
Rameau | 4734 | 2.416 | 1.359 | 0.164 | 5 (estimated) | Core member |
Švejcar |
5031 | 2.436 | 1.535 | 0.148 | 7 (estimated) | Interloper |
Hessen |
5846 | 2.435 | 0.913 | 0.163 | 5 (estimated) | Interloper |
1990 RW3 |
7760 | 2.407 | 1.465 | 0.156 | 9 (estimated) | Core member |
Interlopers
A number of
References
- ^ ISBN 9780816532131.
- ^ .
- doi:10.1086/374807.
- ^ .