B-type asteroids are a relatively uncommon type of

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

aceous

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

, falling into the wider

C-group The C-Group culture is an archaeological culture found in Lower Nubia, which dates from ca. 2400 BCE to ca. 1550 BCE. It was named by George A. Reisner. With no central site and no written evidence about what these people called themselves, Re ...

; the 'B' indicates these objects are spectrally blue. In the asteroid population, B-class objects can be found in the outer

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

, and also dominate the high-

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

Pallas family The Pallas family (''adj. Palladian''; ) is a small asteroid family of B-type asteroids at very high inclinations in the intermediate asteroid belt. The namesake of the family is 2 Pallas, an extremely large asteroid with a mean diameter of about 5 ...

which includes the third-largest asteroid

2 Pallas Pallas (minor-planet designation: 2 Pallas) is the second asteroid to have been discovered, after Ceres. It is believed to have a mineral composition similar to carbonaceous chondrite meteorites, like Ceres, though significantly less hyd ...

. They are thought to be primitive, volatile-rich remnants from the early

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

. There are 65 known B-type asteroids in the SMASS classification, and 9 in the Tholen classification as of March 2015.

Characteristics

Generally similar to the C-type objects, but differing in that the

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

absorption below 0.5 μm is small or absent, and the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...

is rather slightly bluish than reddish. The

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...

also tends to be greater than in the generally very dark C type.

Spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

of B-class objects suggests major surface constituents of anhydrous

silicates In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name i ...

hydrated Drinking is the act of ingesting water or other liquids into the body through the mouth, proboscis, or elsewhere. Humans drink by swallowing, completed by peristalsis in the esophagus. The physiological processes of drinking vary widely among o ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

s, organic polymers,

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

, and

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

s. The closest matches to B-class asteroids have been obtained on carbonaceous

chondrite A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primi ...

meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...

s that have been gently heated in the

laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physicia ...

. The majority of asteroids that have been observed to display cometary-like activity are B-types. 1. Introduction: "the majority of asteroids that have been observed to display cometary-like activity are B-types" Some of these objects display indications of aqueous alteration in the past, and they may have incorporated significant amounts of water ice.

Well studied B-type asteroids

Asteroid 101955 Bennu is a B-type asteroid which is the target of the

OSIRIS-REx OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid-study and sample-return mission. The mission's primary goal is to obtain a sample of at least from 101955 Bennu, a carbona ...

mission. The mission seeks to characterize the asteroid by mapping the surface, studying the

Yarkovsky effect The Yarkovsky effect is a force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum. It is usually considered in relation to meteoroids or small asteroids (about 10 cm to 10 km i ...

, and retrieving a sample of the asteroid to return in 2023. The spacecraft was launched in 2016 and has been at Bennu since December 2018. Other B-type asteroids include: *

24 Themis Themis ( minor planet designation: 24 Themis) is one of the largest asteroids in the asteroid belt. It is also the largest member of the Themistian family. It was discovered by Annibale de Gasparis on 5 April 1853. It is named after Themis, th ...

* 47 Aglaja * 59 Elpis *

85 Io Io (minor planet designation: 85 Io is carbonaceous asteroid from the central region of the asteroid belt, approximately 170 kilometers in diameter. It is an identified Eunomian interloper. Discovery and naming It was discovered by C. H. F ...

* 88 Thisbe * 142 Polana *

213 Lilaea Lilaea (minor planet designation: 213 Lilaea) is a large Asteroid belt, main belt asteroid. It was discovered by German-American astronomer Christian Heinrich Friedrich Peters, C. H. F. Peters on February 16, 1880, in Clinton, Oneida County, New Y ...

241 Germania Germania ( minor planet designation: 241 Germania) is a very large main-belt asteroid. It is classified as a B-type asteroid and is probably composed of dark, primitive carbonaceous material. It was discovered by Robert Luther on 12 September 18 ...

* 282 Clorinde * 335 Roberta * 372 Palma *

383 Janina Janina (minor planet designation: 383 Janina) is a Themistian asteroid, approximately in diameter. It is spectral B-type and is probably composed of primitive carbonaceous chondritic material. It was discovered by Auguste Charlois on 29 Janua ...

431 Nephele Nephele (minor planet designation: 431 Nephele) is a large Themistian asteroid. It is spectral C-type asteroid, C-type and is probably composed of carbonaceous material. It was discovered by Auguste Charlois on 18 December 1897 in Nice. Refer ...

* 531 Zerlina * 541 Deborah * 555 Norma * 560 Delila * 702 Alauda *

704 Interamnia 704 Interamnia is a large F-type asteroid. With a mean diameter of around 330 kilometres, it is the fifth-largest asteroid, after Ceres, Vesta, Pallas and Hygiea. Its mean distance from the Sun is 3.067 ( AU). It was discovered on 2 October 1 ...

767 Bondia 767 Bondia ('' prov. designation:'' ''or'' ) is a Themis asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 23 September 1913, by American astronomer Joel Hastings Metcalf at his observatory ...

895 Helio 895 Helio is a large dark outer main-belt asteroid about 150 km in diameter. It was discovered on 11 July 1918 by German astronomer Max Wolf. It is named after the element helium, whose spectrum was studied by Friedrich Paschen and Carl D ...

* 1021 Flammario * 1331 Solvejg * 1474 Beira * 1484 Postrema *

1539 Borrelly __NOTOC__ Year 1539 ( MDXXXIX) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. Events January–June * January – Toungoo–Hanthawaddy War – Battle of Naungyo, Burm ...

* 1655 Comas Sola *

1705 Tapio Seventeen or 17 may refer to: *17 (number), the natural number following 16 and preceding 18 * one of the years 17 BC, AD 17, 1917, 2017 Literature Magazines *Seventeen (American magazine), ''Seventeen'' (American magazine), an American magazi ...

* 1724 Vladimir *

2382 Nonie 38 may refer to: *38 (number), the natural number following 37 and preceding 39 *one of the years 38 BC, AD 38, 1938, 2038 *.38, a caliber of firearms and cartridges **.38 Special, a revolver cartridge *'' Thirty-Eight: The Hurricane That Transfo ...

* 2446 Lunacharsky *

2527 Gregory 5 (five) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typ ...

* 2629 Rudra * 2659 Millis * 2708 Burns *

2772 Dugan 77 may refer to: * 77 (number) * one of the years 77 BC, AD 77, 1977, 2077 Music * 77 (band), a Spanish hard rock band * ''77'' (Matt Kennon album) * '' Talking Heads: 77'', debut album by Talking Heads * ''77'' (Nude Beach album), an album by t ...

2809 Vernadskij 8 (eight) is the natural number following 7 and preceding 9. In mathematics 8 is: * a composite number, its proper divisors being , , and . It is twice 4 or four times 2. * a power of two, being 2 (two cubed), and is the first number of t ...

2816 Pien __NOTOC__ Year 816 ( DCCCXVI) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events By place Europe * October 5 – King Louis the Pious (son of Charlemagne) is crowned emperor of ...

* 2973 Paola *

3000 Leonardo 3000 Leonardo, provisional designation , is a carbonaceous background asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 2 March 1981, by American astronomer Schelte Bus at the Siding Spring Ob ...

* 3074 Popov * 3200 Phaethon * 3566 Levitan * 3579 Rockholt * 3581 Alvarez *

3627 Sayers 36 may refer to: * 36 (number), the natural number following 35 and preceding 37 * One of these years of Gregorian or Julian calendars: ** 36 BC, 1st century BCE ** AD 36, 1st century ** 1936, 20th century ** 2036, 21st century Arts and entertai ...

* 3647 Dermott * 4124 Herriot * 4396 Gressmann * 4686 Maisica * 4997 Ksana *

5079 Brubeck 5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on eac ...

* 5102 Benfranklin * 5133 Phillipadams * 5222 Ioffe *

5234 Sechenov 5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on eac ...

5330 Senrikyu __NOTOC__ Year 533 (Roman numerals, DXXXIII) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Justinian I, Iustinianus without collea ...

* 5344 Ryabov *

(5690) 1992 EU Year 569 (Roman numerals, DLXIX) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. The denomination 569 for this year has been used since the early medieval period, when the Anno Domini calendar ...

* 6500 Kodaira * (7753) 1988 XB * * (65679) 1989 UQ *

References

{{Small Solar System bodies Asteroid spectral classes

Characteristics

Well studied B-type asteroids

See also

References