S-type asteroid

SS-typestony asteroidsstonysilicaceousstony asteroidS-S-type asteroidsstony compositionS-complex
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name.wikipedia
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Asteroid

asteroidsminor bodyMinor Planet
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name.
Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, and S-type.

Asteroid belt

main-beltMain beltmain-belt asteroid
They are dominant in the inner part of the asteroid belt within 2.2 AU, common in the central belt within about 3 AU, but become rare farther out.
Individual asteroids within the asteroid belt are categorized by their spectra, with most falling into three basic groups: carbonaceous (C-type), silicate (S-type), and metal-rich (M-type).

15 Eunomia

Eunomia(15) Eunomia
The largest is 15 Eunomia (about 330 km wide across its longest dimension), with the next largest members by diameter being 3 Juno, 29 Amphitrite, 532 Herculina and 7 Iris.
It is the largest of the stony (S-type) asteroids, and somewhere between the 8th- and 12th-largest main-belt asteroid overall (uncertainty in diameters causes uncertainty in its ranking).

3 Juno

Juno(3) Junoasteroid
The largest is 15 Eunomia (about 330 km wide across its longest dimension), with the next largest members by diameter being 3 Juno, 29 Amphitrite, 532 Herculina and 7 Iris.
It is the 11th-largest asteroid, and one of the two largest stony (S-type) asteroids, along with 15 Eunomia.

29 Amphitrite

Amphitrite
The largest is 15 Eunomia (about 330 km wide across its longest dimension), with the next largest members by diameter being 3 Juno, 29 Amphitrite, 532 Herculina and 7 Iris.
Amphitrite (minor planet designation: 29 Amphridite) is one of the largest S-type asteroids, approximately 200 km in diameter, and probably third largest after Eunomia and Juno, although Iris and Herculina are similar in size.

C-type asteroid

CcarbonaceousC-type
Approximately 17% of asteroids are of this type, making it the second most common after the carbonaceous C-type.
Consequently, whereas a number of S-type asteroids can normally be viewed with binoculars at opposition, even the largest C-type asteroids require a small telescope.

7 Iris

Iris
The largest is 15 Eunomia (about 330 km wide across its longest dimension), with the next largest members by diameter being 3 Juno, 29 Amphitrite, 532 Herculina and 7 Iris.
It is classified as an S-type asteroid, meaning that it has a stony composition.

L-type asteroid

LL-typeL-
These asteroids were described as "featureless" S-types in the Tholen classification.

K-type asteroid

K-typeKtype K
These asteroids were described as "featureless" S-types in the Tholen classification.

Eunomia family

EunomiaEunomian asteroidEunomian interloper
The Eunomia or Eunomian family (FIN: 502) is a large asteroid family of S-type asteroids named after the asteroid 15 Eunomia.

Flora family

FloraFlorian asteroidFlorian
Florian; FIN: 402; also known as Ariadne family'') is a prominent family of stony asteroids located in the inner region of the asteroid belt.

Asteroid family

familybackground populationJovian background population

Q-type asteroid

QQ-typeQ-type asteroids
In the Tholen classification, the S-type is a very broad grouping which includes all the types in the SMASS S-group except for the A, Q, and R, which have particularly strong "stony" absorption features around 1 μm.
There are absorption features shortwards and longwards of 0.7 μm, and the spectrum is generally intermediate between the V and S-type.

Koronis family

KoronisKoronian asteroidKoronian
The Koronis or Koronian family (FIN: 605), also known as the Lacrimosa family, is a very large asteroid family of stony asteroids, located in the outer region of the asteroid belt.

532 Herculina

Herculina
The largest is 15 Eunomia (about 330 km wide across its longest dimension), with the next largest members by diameter being 3 Juno, 29 Amphitrite, 532 Herculina and 7 Iris.

Eos family

EosEoan asteroidEos asteroid family
Asteroids in the Eos family resemble the S-type asteroid category.

Asteroid spectral types

B–Vspectral typeSMASS classification
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. In the Tholen classification, the S-type is a very broad grouping which includes all the types in the SMASS S-group except for the A, Q, and R, which have particularly strong "stony" absorption features around 1 μm.
The three categories were labelled "C" for dark carbonaceous objects, "S" for stony (silicaceous) objects, and "U" for those that did not fit into either C or S. This basic division of asteroid spectra has since been expanded and clarified.

Phocaea family

PhocaeaPhocaea asteroidPhocaeas
Phocaea asteroids are of stony S-type composition and have orbits with eccentricities greater than 0.1 and inclinations between 18 and 32°.

Nysa family

NysaNysa–Polana complexPolana family

Silicon dioxide

silicasiliceousSiO 2
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name.

Mineralogy

mineralogistmineralogicalmineralogists
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name.

Albedo

albedosreflectivitygeometrical albedo
S-type asteroids, with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates.

Magnesium

MgMg 2+ Mg2+
S-type asteroids, with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates.

Silicate

silicatessilicasilicified
S-type asteroids, with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates.