page_title: 731 Sorga
section_title: Rotation period and poles
hierarchical_section_title: 731 Sorga / Physical characteristics / Rotation period and poles
caption_attribution_description: English: A three-dimensional model of 731 Sorga that was computed using light curve inversion techniques.
context_page_description: 731 Sorga is a highly elongated background asteroid from the outer regions of the asteroid belt, approximately 38 kilometers in diameter. It was discovered on 15 April 1912, by German astronomer Adam Massinger at the Heidelberg-Königstuhl State Observatory in soutwest Germany. The C-type and X-type asteroid has a rotation period of 8.2 hours. It was named Sorga, meaning "the heavens" in the Indonesian language.
context_section_description: In April 2005, a rotational lightcurve of Sorga was obtained from photometric observations by Brian Warner at his Palmer Divide Observatory (716) in Colorado. Analysis gave a classically shaped bimodal lightcurve with a well-defined rotation period of (8.184±0.005) hours and a high brightness variation of (0.52±0.02) magnitude, indicative of its elongated shape (U=3). In February 2009, Warner revisited Sorga and determined a very similar period of (8.192±0.002) hours though with a much lower amplitude of (0.19±0.02) magnitude (U=3).
  In January 2010, astronomers at the Palomar Transient Factory measured a period of 8.188±0.0023 hours with an amplitude of 0.72 magnitude (U=2). Additional observations by Christophe Demeautis in September 2017, and by Bruno Christmann in April 2020, gave a period of (8.186±0.003) and (8.1865±0.0003) hours with an amplitude of 0.54±0.02 and 0.57±0.02 magnitude, respectively (U=3–/3).
  In 2016, a modeled lightcurve rendered a concurring sidereal period of 8.18633±0.00002 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys (950). The study also determined two spin axes of (83.0°, 40.0°) and (275.0°, 21.0°) in ecliptic coordinates (λ, β).
caption: Lightcurve-based 3D shape model of Sorga
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