1692 Subbotina, provisional designation , is a dark background

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

from the central region of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

, approximately in diameter. The carbonaceous Cg-type asteroid has a

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

of 9.2 hours. It was discovered by

Grigory Neujmin Grigory Nikolayevich Neujmin (; – 17 December 1946) was a Georgian–Russian astronomer, native of Tbilisi in Georgia (country), Georgia, and a discoverer of numerous minor planets as well as 6 periodic comet, periodic and a List of hyperbolic ...

at the Crimean

Simeiz Observatory Simeiz Observatory (also spelled Simeis or Simeïs) was an astronomy research observatory until the mid-1950s. It is located on Mount Koshka, Crimea, by the town of Simeiz. Part of the Crimean Astrophysical Observatory, it is currently used fo ...

in 1936, and later named after Soviet mathematician and astronomer

Mikhail Subbotin Mikhail Fedorovich Subbotin (, 29 June 1893 – 26 December 1966) was a Soviet mathematician and astronomer who calculated orbits of planets and comets. He worked on general properties of motion in the ''n''-body problem. Biography and educati ...

Discovery

''Subbotina'' was discovered by Soviet-Russian astronomer

at the Crimean

on 16 August 1936. On the following night, astronomer

Karl Reinmuth Karl Wilhelm Reinmuth (4 April 1892 in Heidelberg – 6 May 1979 in Heidelberg) was a German astronomer and a prolific discoverer of 395 minor planets. Scientific career From 1912 to 1957, Reinmuth was working as an astronomer at the He ...

independently discovered the body at the

Heidelberg Observatory Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...

in Germany. The asteroid was first observed as at the discovering observatory in September 1927. Its first used observation was made at Heidelberg in July 1931, extending the body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

by 5 years prior to its official discovery observation in 1936.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named in memory of eminent Soviet mathematician and astronomer,

(1893–1966), long-time director of the Institute of Theoretical Astronomy (ITA) in former Leningrad. The lunar crater '' Subbotin'' was also named in his honour. The official was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

on 1 June 1967 ().

Orbit and classification

''Subbotina'' is a non-

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

asteroid from the main belt's background population. It orbits the Sun in the central asteroid belt at a distance of 2.4–3.2 AU once every 4 years and 8 months (1,700 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longe ...

of 2.79 AU). Its orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.14 and an

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

of 2 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

Physical characteristics

In the SMASS-II taxonomy, ''Subbotina'' has been characterized as a dark Cg-type, a subtype of the wider group of carbonaceous

C-type asteroid C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

s with low albedos.

Rotation period

In October 2006, a rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

of ''Subbotina'' was obtained from photometric observations by Italian

Silvano Casulli __NOTOC__ Vincenzo Silvano Casulli, usually known as Silvano Casulli (25 August 1944 – 24 July 2018

and French

Laurent Bernasconi This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth object, near-Earth and main-belt asteroids, Jupiter trojans and Distant minor planet, distant ob ...

, both amateur astronomers. Lightcurve analysis gave a well-defined

of hours with a brightness variation of in

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

(). Somewhat higher amplitudes of 0.42 and 0.62 magnitude were found by the NEOWISE mission.

Diameter and albedo

According to the space-based surveys carried out by the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite (Dutch language, Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a astronomical survey, survey of the entire night sky at infrared wavelengths. Launched on 25 Janu ...

, the Japanese

Akari AKARI (ASTRO-F) was an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket ...

satellite, and NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE L ...

with its subsequent

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and nu ...

mission, ''Subbotina'' measures between 34.8 and 43.0 kilometers in diameter and its surface has a notably low

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

in the range of 0.02 to 0.049. The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.04 and a diameter of 36.5 kilometers with an absolute magnitude of 11.3.