View source for R-type asteroid

'''R-type asteroids''' are moderately bright, relatively uncommon inner-belt [[asteroid]]s that are spectrally intermediate between the [[V-type asteroid|V]] and [[A-type asteroid]]s.  The spectrum shows distinct [[olivine]] and [[pyroxene]] features at 1 and 2 [[micrometre]]s, with a possibility of [[plagioclase]]. Shortwards of 0.7 μm the spectrum is very reddish.

The [[IRAS]] mission has classified [[4 Vesta]], [[246 Asporina]], [[349 Dembowska]], [[571 Dulcinea]] and [[937 Bethgea]] as type R; however, the re-classification of Vesta, the V archetype, is debatable.  Of these bodies, only [[349 Dembowska]] is recognized as being type R when all wavelengths are taken into account.

==List==
As of February 2019, at least 5 asteroids have been classified as R-type:<ref name="SBDB">{{cite web
  |title=JPL Small-Body Database Search Engine: spec. type <nowiki>=</nowiki> R (SMASSII)
  |publisher=JPL Solar System Dynamics
  |url=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=R;table_format=HTML;max_rows=10;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
  |accessdate=2019-03-17}}</ref>
{| class="wikitable"
! [[Minor planet designation|Designation]] !! Class !! Diam. || Refs
|-
| [[349 Dembowska]] || {{small|main-belt}} || {{small|139.77 km}} || {{small|{{MPC|349}}{{·}}{{JPL|349}}}}
|-
| [[1904 Massevitch]] || {{small|main-belt}} || {{small|13.503 km}} || {{small|{{MPC|1904}}{{·}}{{JPL|1904}}}}
|-
| [[2371 Dimitrov]] || {{small|main-belt}} || {{small|7.465 km}} || {{small|{{MPC|2371}}{{·}}{{JPL|2371}}}}
|-
| [[5111 Jacliff]] || {{small|main-belt}} || {{small|6.447 km}} || {{small|{{MPC|5111}}{{·}}{{JPL|5111}}}}
|-
| [[(257838) 2000 JQ66]] || {{small|Amor}} || {{small|0.78 km}} || {{small|{{MPC|257838}}{{·}}{{JPL|257838}}}}
|-
! colspan=4 style="font-weight: normal; padding: 8px; font-size: smaller;" | Diameter: averaged estimates only; may change over time
|}

==References==
{{RefList}}

==See also==
*[[Asteroid spectral types]]

{{Asteroids}}
{{Small Solar System bodies}}

{{DEFAULTSORT:R-Type Asteroid}}
[[Category:Asteroid spectral classes]]
[[Category:R-type asteroids]]


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