11066 Sigurd (

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

) is a stony

contact binary In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontac ...

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 ...

classified as

near-Earth object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...

of the

Apollo group Apollo Education Group, Inc. is an American corporation based in the South Phoenix area of Phoenix, Arizona, with an additional corporate office in Chicago, Illinois. It is privately-owned by a consortium of investors including The Vistria Grou ...

of asteroids, approximately 2.5 kilometers in diameter. It was discovered on 9 February 1992 by American astronomer couple

Carolyn Carolyn is a female given name, a variant of Caroline. Other spellings include Carolin, Karolyn, Carolyne, Carolynn or Carolynne. Caroline itself is one of the feminine forms of Charles. List of notable people * Carolyn Bennett (born 1950 ...

and

Eugene Shoemaker Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997) was an American geologist. He co-discovered Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was telev ...

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

, California, and named after

Sigurd Sigurd ( ) or Siegfried (Middle High German: ''Sîvrit'') is a legendary hero of Germanic heroic legend, who killed a dragon — known in Nordic tradition as Fafnir () — and who was later murdered. In the Nordic countries, he is referred t ...

, a hero from Norse mythology.

Orbit and classification

Sigurd orbits the Sun in the inner main-belt at a distance of 0.9–1.9 AU once every 1 years and 8 months (600 days). 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 0.38 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 37 ° 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 ...

. A first

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This ha ...

was taken at the Australian

Siding Spring Observatory Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a coll ...

in 1978, and it was identified as at Palomar in 1987. Both observations remained unused. 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 with its official discovery observation at Palomar in 1992. It has an ''Earth

minimum orbital intersection distance Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of ...

'' of , which corresponds to 46.1 lunar distances.

Physical characteristics

In the SMASS taxonomy, Sigurd is a relatively rare

K-type asteroid K-type asteroids are relatively uncommon asteroids with a moderately reddish spectrum shortwards of 0.75 μm, and a slight bluish trend longwards of this. They have a low albedo. Their spectrum resembles that of CV and CO meteorites. A larger K ty ...

, which fall into the broader stony S-complex. It has also been grouped into the common

S-type asteroid S-type (stony-type or silicaceous-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 ...

. The ExploreNEOs Warm Spitzer program, using the

NASA Infrared Telescope Facility The NASA Infrared Telescope Facility (NASA IRTF) is a telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. It was first built to support the Voyager program, Voyager missions and is now the US n ...

on Mauna Kea Observatory in Hawaii, classifies ''Sigurd'' as a Sr-type, which transitions to the

R-type asteroid R-type asteroids are moderately bright, relatively uncommon inner-belt asteroids that are spectrally intermediate between the V and A-type asteroids. The spectrum shows distinct olivine and pyroxene features at 1 and 2 micrometres, with a possibil ...

Contact binary

Radiometric observations at

Arecibo Observatory The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science F ...

revealed that Sigurd is a

, composed of two lobes in contact with each other. The more or less

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

al lobes are elongated and joined on their long axis. The body has an

axial tilt In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbita ...

of 50° to 130°. The observing astronomers also note, that more than 10% of all larger (> 200 meters) near-Earth objects observed by radar are such contact binaries.

Photometry

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 ...

s obtained from photometric observations by

Petr Pravec Petr Pravec (born September 17, 1967) is a Czech astronomer and a discoverer of minor planets, born in Třinec, Czech Republic. Pravec is a prolific discoverer of binary asteroids, expert in photometric observations and rotational lightcurves ...

, Brian Warner and by a group of German and Ukrainian astronomers, gave a well-defined

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 8.4958 to 8.51 hours. The analysis of the constructed

s also gave a high brightness amplitude between 0.97 and 1.15

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 ...

, which is indicative that ''Sigurd'' has a non-spheroidal shape ().

Diameter and albedo

According to the survey carried out by 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, Sigurd measures between 2.10 and 2.778 kilometers in diameter and its surface has an

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 ...

of 0.190 and 0.29, respectively. Observations by the ExploreNEOs survey give a higher albedo of 0.38. The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.18 and calculates a diameter of 2.86 kilometers with an absolute magnitude of 15.2, while radiometric observations of Sigurd gave a maximum dimensions of 4.2 kilometers.

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 after

, a legendary hero in

Norse mythology Norse, Nordic, or Scandinavian mythology, is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia as the Nordic folklore of the modern period. The ...

. In the

Völsunga saga The ''Völsunga saga'' (often referred to in English as the ''Volsunga Saga'' or ''Saga of the Völsungs'') is a legendary saga, a late 13th-century prose rendition in Old Norse of the origin and decline of the Völsung clan (including the story ...

, Sigurd rides through a ring of fire to awaken the shieldmaiden

Brynhild Brunhild, also known as Brunhilda or Brynhild ( , , or ), is a female character from Germanic heroic legend. She may have her origins in the Visigothic princess and queen Brunhilda of Austrasia. In the Norse tradition, Brunhild is a shield ...

(), and later dies in a fight with

Odin Odin (; from ) is a widely revered god in Norse mythology and Germanic paganism. Most surviving information on Odin comes from Norse mythology, but he figures prominently in the recorded history of Northern Europe. This includes the Roman Em ...

(). Sigurd is also known as the dragon-slayer Siegfried in the German poem '' The Song of the Nibelungs''. The approved naming citation 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 23 May 2000 ().

References

External links

IAUC 5459 (discovery )
Central Bureau for Astronomical Telegrams, 27 February 1992

Robert Johnston, list at jonstonsarchive.net, 25 March 2017

Lance A. M. Benner, ASA/JPL Asteroid Radar Research
(11066) Sigurd
at NEODyS-2
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

Observatoire de Genève, Raoul Behrend * * * {{DEFAULTSORT:Sigurd 011066 Discoveries by Eugene Merle Shoemaker Discoveries by Carolyn S. Shoemaker Named minor planets 011066 011066 011066 19920209