|Discovered by||Annibale de Gasparis|
|Discovery date||September 19, 1852|
|Main belt (Massalia family)|
|Epoch October 22, 2004 (JD 2453300.5)|
|Aphelion||411.911 Gm (2.753 AU)|
|Perihelion||308.699 Gm (2.064 AU)|
|360.305 Gm (2.408 AU)|
|1365.261 d (3.74 a)|
Average orbital speed
|Dimensions||160×145×130 km |
|Mass||5.2×1018 kg |
|0.3374 d (8.098 h) |
max: 265 K (-8°C)
|8.3 to 12.0|
|0.186" to 0.058"|
Massalia is an S-type asteroid. It orbits at very low inclination in the intermediate main belt, and is by far the biggest asteroid in the Massalia family. The remaining family members are pieces blown off by a cratering event on Massalia 
Massalia has an above-average density for S-type asteroids, similar to the density of silicate rocks. As such, it appears to be a solid un-fractured body, which is rare among asteroids of its size. Apart from the few biggest bodies over 400 km in diameter, such as 1 Ceres and 4 Vesta, most asteroids appear to have been fractured a lot.
Lightcurve analysis indicates that Massalia's pole points towards either ecliptic coordinates (β, λ) = (45°, 10°) or (β, λ) = (45°, 190°) with a 10° uncertainty. This gives an axial tilt of 45°in both cases. The shape reconstruction from lightcurves has been described as quite spherical with large planar, nonconvex parts of the surface.
- Supplemental IRAS Minor Planet Survey[dead link]
- M. Kaasalainen et al. (2002). "Models of Twenty Asteroids from Photometric Data". Icarus 159: 369. http://www.rni.helsinki.fi/~mjk/IcarPIII.pdf.
- J. Bange (1998). "An estimation of the mass of asteroid 20-Massalia derived from the HIPPARCOS minor planets data". Astronomy & Astrophysics 340: L1. Archived from the original on 2012-02-12. https://www.webcitation.org/65OTHDg6u.
- PDS lightcurve data[dead link]
- PDS spectral class data Archived 17 January 2010 at WebCite
- Donald H. Menzel and Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd edition ed.). Boston, MA: Houghton Mifflin. p. p. 391. ISBN 978-0-395-34835-2.CS1 maint: extra text (link)
- D. Vokrouhlický et al. (2006). "Yarkovsky/YORP chronology of asteroid families". Icarus 182: 118.