Английская Википедия:11066 Sigurd

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Шаблон:Short description Шаблон:Use dmy dates Шаблон:Infobox planet 11066 Sigurd, provisional designation Шаблон:Mp, is a stony, rare-typeШаблон:Clarify asteroid and elongated contact binary, classified as near-Earth object of the Apollo group of asteroids, approximately 2.5 kilometers in diameter.

It was discovered on 9 February 1992 by American astronomer couple Carolyn and Eugene Shoemaker at Palomar Observatory, California, and named after Sigurd, 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 of 0.38 and an inclination of 37° with respect to the ecliptic. A first precovery was taken at the Australian Siding Spring Observatory in 1978, and it was identified as Шаблон:Mp at Palomar in 1987. Both observations remained unused. The body's observation arc begins with its official discovery observation at Palomar in 1992.

It has an Earth minimum orbital intersection distance of Шаблон:Convert, which corresponds to 46.1 lunar distances.

Physical characteristics

In the SMASS taxonomy, Sigurd is a relatively rare K-type asteroid, which fall into the broader stony S-complex. It has also been grouped into the common S-type asteroid. The ExploreNEOs Warm Spitzer program, using the NASA Infrared Telescope Facility on Mauna Kea Observatory in Hawaii, classifies Sigurd as a Sr-type, which transitions to the R-type asteroids.

Contact binary

Radiometric observations at Arecibo Observatory revealed that Sigurd is a contact binary, composed of two lobes in contact with each other. The more or less ellipsoidal lobes are elongated and joined on their long axis. The body has an axial tilt 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 lightcurves obtained from photometric observations by Petr Pravec, Brian Warner and by a group of German and Ukrainian astronomers, gave a well-defined rotation period of 8.4958 to 8.51 hours. The analysis of the constructed lightcurves also gave a high brightness amplitude between 0.97 and 1.15 magnitude, which is indicative that Sigurd has a non-spheroidal shape (Шаблон:Small).

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Sigurd measures between 2.10 and 2.778 kilometers in diameter and its surface has an albedo 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 an maximum dimensions of 4.2 kilometers.

Naming

This minor planet was named after Sigurd, a legendary hero in Norse mythology. In the Völsunga saga, Sigurd rides through a ring of fire to awaken the shieldmaiden Brynhild (Шаблон:Mp), and later dies in a fight with Odin (Шаблон:Mp). 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 on 23 May 2000 (Шаблон:Small).

External links

• IAUC 5459 (discovery Шаблон:Mp), Central Bureau for Astronomical Telegrams, 27 February 1992
• Contact Binary Asteroids and Comets, Robert Johnston, list at jonstonsarchive.net, 25 March 2017
• Binary and Ternary near-Earth Asteroids detected by radar, Lance A. M. Benner, ASA/JPL Asteroid Radar Research
• (11066) Sigurd at NEODyS-2
• Asteroid Lightcurve Database (LCDB), query form (info Шаблон:Webarchive)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdRШаблон:Snd Observatoire de Genève, Raoul Behrend
• Шаблон:NeoDys
• Шаблон:ESA-SSA
• Шаблон:JPL small body