Astronomy:A-type asteroid
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Short description: Asteroid class
A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 μm olivine feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated mantle of an asteroid, and appear to have a high density. One survey found that 7 similar A-, V- and X-type asteroids had an average density of 3.6 g/cm3.[1] A-type asteroids were once thought to be rare, but a 2026 study of data from the Gaia spacecraft showed that they were quite common among members of the Flora and Vesta asteroid families, with an overall abundance among all main belt asteroids of about 2%, significantly higher than earlier estimates.[2]
List
As of August 2024, 17 A-type asteroids had been discovered:[3]
| Designation | Class | Diam. | Refs |
|---|---|---|---|
| 246 Asporina | main-belt | 50.9 km | MPC · JPL |
| 289 Nenetta | main-belt | 37.6 km | MPC · JPL |
| 446 Aeternitas | main-belt | 53.6 km | MPC · JPL |
| 863 Benkoela | main-belt | 38.7 km | MPC · JPL |
| 1126 Otero | main-belt | 11.0 km | MPC · JPL |
| 1600 Vyssotsky | main-belt | 7.4 km | MPC · JPL |
| 1951 Lick | Mars-crossing | 5.6 km | MPC · JPL |
| 2234 Schmadel | main-belt | 9.5 km | MPC · JPL |
| 2423 Ibarruri | Mars-crossing | 4.9 km | MPC · JPL |
| 2501 Lohja | main-belt | 10.2 km | MPC · JPL |
| 2715 Mielikki | main-belt | 13.3 km | MPC · JPL |
| 2732 Witt | main-belt | 11.0 km | MPC · JPL |
| 3352 McAuliffe | Amor | 2.1 km | MPC · JPL |
| 4142 Dersu-Uzala | Mars-crossing | 7.1 km | MPC · JPL |
| 4713 Steel | main-belt | 6.3 km | MPC · JPL |
| 4982 Bartini | main-belt | 8.0 km | MPC · JPL |
| 5641 McCleese | Mars-crossing | 5.7 km | MPC · JPL |
| Diameter: averaged estimates only; may change over time | |||
See also
References
- ↑ P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
- ↑ M. Delbo et al. (7 January 2026). "Gaia and IRTF abundance of A-type main-belt asteroids". Astronomy & Astrophysics 705 (A46). doi:10.1051/0004-6361/202556827. https://www.aanda.org/articles/aa/full_html/2026/01/aa56827-25/aa56827-25.html.
- ↑ "JPL Small-Body Database Search Engine: spec. type = A (SMASSII)". JPL Solar System Dynamics. http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;c1_group=OBJ;c1_item=Ax;c1_op=%3D;c1_value=A;table_format=HTML;max_rows=50;format_option=comp;c_fields=AcBhBgBjBiBnBsAiAx;.cgifields=format_option;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=com_orbit_class&query=1.
External links
- Mineralogic and Temperature-Induced Spectral Investigations of A-type Asteroids: (246) Asporina and (446) Aeternitas, V. Reddy, Lunar and Planetary Science XXXVI (2005)
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