1121 Natascha ( ''prov. designation'': ) is a

background asteroid An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An a ...

from the central regions of the

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 ...

. It was discovered on 11 September 1928, by Soviet astronomer

Pelageya Shajn Pelageya Fedorovna Shajn, ''née'' Sannikova (Пелагея Фёдоровна Шайн) (22 September 1894 – 27 August 1956), was a Russian astronomer in the Soviet Union, and the first woman credited with the discovery of a minor planet, at ...

at the

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 f ...

on the Crimean peninsula. The presumed

S-type asteroid S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second ...

has

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 13.2 hours and measures approximately in diameter. It was named for Natasha Tichomirova, daughter of astronomer

Grigory Neujmin Grigory Nikolayevich Neujmin (russian: Григорий Николаевич Неуймин; – 17 December 1946) was a Georgian–Russian astronomer, native of Tbilisi in Georgia, and a discoverer of numerous minor planets as well as 6 periodi ...

Orbit and classification

''Natascha'' is a non-

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

asteroid from the main belt's background population. Conversely, the asteroid is also considered a core member of the disputed Astraea family. It orbits the Sun in the

central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

main-belt at a distance of 2.1–3.0 AU once every 4 years and 1 month (1,484 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 long ...

of 2.55 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-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.16 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 Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 6 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

. The asteroid was first observed as at Simeiz Observatory in March 1918. 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 ...

begins at

Heidelberg Observatory Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. ...

in February 1930, or 17 months after its official discovery observation at Simeiz.

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 as a birthday present for Soviet hydrogeologist Natasha (Natalia) Tichomirova, daughter of

, who was an astronomer at the discovering Simeiz Observatory and prolific

discoverer of minor planets 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 and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 numb ...

himself (). The author of the ''Dictionary of Minor Planet Names'',

Lutz Schmadel Lutz Dieter Schmadel (2 July 1942, in Berlin – 21 October 2016) was a German astronomer and a prolific discoverer of asteroids, who worked at the Astronomisches Rechen-Institut (ARI) of the University of Heidelberg. His special interest was t ...

, learned about the naming circumstances from Crimean astronomers N. Solovaya, Nataliya Sergeevna Samoilova-Yakhontova and

Nikolai Chernykh Nikolai Stepanovich Chernykh (russian: Никола́й Степа́нович Черны́х) (6 October 1931 – 25 May 2004Казакова, Р.К. Памяти Николая Степановича Черных'. Труды Государст ...

''(also see and )''.

Physical characteristics

''Natascha'' is an assumed, stony

Rotation period and poles

In May 2012, a rotational

lightcurve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

of ''Natascha'' was obtained from photometric observations by astronomers at the

Oakley Southern Sky Observatory This is a list of observatory codes (IAU codes or MPC codes) published by the Minor Planet Center. For a detailed description, ''see observations of small Solar System bodies Observations of minor planets as well as comets and natural satellites ...

in Australia. Lightcurve analysis gave a well-defined

of 13.197 hours with a brightness variation of 0.51

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 ...

(). A high brightness amplitude typically indicates a non-spherical shape. In 2016, a modeled lightcurve was published using photometric data from the Lowell Photometric Database. Lightcurve inversion gave a concurring period of hours, as well as two spin axes of (16.0°, 59.0°) and (209.0°, 50.0°) in

ecliptic coordinates The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small Solar System bodi ...

(λ, β).

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

, ''Natascha'' measures between 12.859 and 14.52 kilometers in diameter and its surface has an

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, 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 ...

between 0.160 and 0.294. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 14.89 kilometers based on an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 11.5.

References

External links

Lightcurve Database Query
(LCDB), at ''www.minorplanet.info''
Dictionary of Minor Planet Names
(1121) Natascha, Google books

– ''Geneva Observatory'',

Raoul Behrend 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 and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 numb ...

Discovery Circumstances: Numbered Minor Planets (1)-(5000)
– Minor Planet Center * * {{DEFAULTSORT:Natascha 001121 Discoveries by Pelageya Shajn Named minor planets 19280911