1016 Anitra, provisional designation , is a stony Florian

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. ...

and suspected asynchronous binary system from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 31 January 1924, by German 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 Lande ...

at the

Heidelberg-Königstuhl State Observatory Heidelberg-Königstuhl State Observatory (german: Landessternwarte Heidelberg-Königstuhl) is a historic astronomical observatory located near the summit of the Königstuhl hill in the city of Heidelberg in Germany. The predecessor of the curre ...

in southwest Germany. The asteroid was likely named after the fictional character Anitra from

Henrik Ibsen Henrik Johan Ibsen (; ; 20 March 1828 – 23 May 1906) was a Norwegian playwright and theatre director. As one of the founders of modernism in theatre, Ibsen is often referred to as "the father of realism" and one of the most influential playw ...

's drama ''

Peer Gynt ''Peer Gynt'' (, ) is a five- act play in verse by the Norwegian dramatist Henrik Ibsen published in 1876. Written in Norwegian, it is one of the most widely performed Norwegian plays. Ibsen believed ''Per Gynt'', the Norwegian fairy tale on wh ...

''.

Orbit and classification

''Anitra'' is a member of the Flora family (), a giant

asteroid family 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 ...

and the largest family of stony asteroids in the main-belt. It orbits the Sun in the

inner Interior may refer to: Arts and media * ''Interior'' (Degas) (also known as ''The Rape''), painting by Edgar Degas * ''Interior'' (play), 1895 play by Belgian playwright Maurice Maeterlinck * ''The Interior'' (novel), by Lisa See * Interior de ...

main-belt at a distance of 1.9–2.5 AU once every 3 years and 4 months (1,208 days). Its orbit has an eccentricity of 0.13 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 asteroid'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, 12 days after to its official discovery observation.

Physical characteristics

In the

SMASS classification An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiat ...

, ''Anitra'' is a common, stony

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 ...

Rotation period

In November 2015, a rotational lightcurve of ''Anitra'' was obtained from photometric observations by an international collaborations of astronomers who combined their observational results. Lightcurve analysis gave a

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 5.92951 hours with a brightness amplitude of 0.30 magnitude ().

Binary system

''Anitra'' is a suspected asynchronous binary asteroid, a system with a fairly large separation, for which tidal forces have been insufficient to synchronize the periods within the system's lifetime. The likely minor-planet moon has a rotation period of 2.609 hours and is thought to orbit its primary every 240 hours. The results, however, are still tentative. More than 100 known binaries from the asteroid belt have already been discovered.

Diameter and albedo

According to the survey carried out by the NEOWISE 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, ...

, ''Anitra'' measures 9.539 and 10.302 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 ...

of 0.2728 and 0.308, respectively. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony S-type asteroids of 0.20 and calculates a diameter of 12.97 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 11.8.

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 probably named after the Arabian dancer Anitra, daughter of a Bedouin chief in

's drama ''

'', a five-act play in verse. The music was composed by Edvard Grieg who named one piece "Anitra's Dance". The minor planets and are named after Grieg and Ibsen, respectively. The official naming citation is based on research by

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 ...

and feedback from astronomers R. Bremer and

I. van Houten-Groeneveld Ingrid van Houten-Groeneveld (; 21 October 1921 – 30 March 2015) was a Dutch astronomer. Background In a jointly credited trio with Tom Gehrels and her husband Cornelis Johannes van Houten, she was the discoverer of many thousands of astero ...

Orbit and classification

Physical characteristics

Rotation period

Binary system

Diameter and albedo

Naming

Notes

References

External links