It was the secondAten asteroid to be discovered after2062 Aten, the family's namesake, also discovered by Helin in 1976. The group of Aten asteroids feature asemi-major axis of less than 1 au. Of this group, Ra-Shalom has one of the smallest semi-major axes, just 0.832 au.
The asteroid has an Earthminimum orbital intersection distance of 0.1496 au (22.4 million kilometres) which corresponds to 58.3lunar distances, far too large to make it apotentially hazardous object.[1] It also comes within 30 million kilometres (0.2 au) of Mars, Venus and Mercury. The closest approaches are to Mercury, to about 0.0784 astronomical units (11.7 million kilometres).[21]
Theminor planet's composed named was chosen by the discoverer to commemorate theCamp David Peace Accords between Egypt and Israel in September 1978, and as a symbol for the universal hope for peace.Ra is the Egyptian Sun-god, who symbolizes enlightenment and life, whileShalom is the traditional Hebrew greeting meaning peace.[3] The officialnaming citation was published by theMinor Planet Center on 1 November 1978 (M.P.C. 4548).[22]
Ra-Shalom has been characterized as aC-type andX-type asteroid on theTholen andSMASS taxonomic scheme, respectively.[1] It has also been characterized as aK-type asteroid.[9] In 1981, the asteroid was detected using radar, revealing a relatively smooth surface at decimeter scales.[23]
In August 2016, a rotationallightcurve ofRa-Shalom was obtained from photometric observations by American astronomerBrian Warner. Lightcurve analysis gave a well-definedrotation period of 19.89 hours with a brightness amplitude of 0.55magnitude (U=3).[18]
A large number of previous photometric observations gave a period between 19.79 and 19.8201 hours with a brightness amplitude between 0.3 and 0.41magnitude.[9][14][15][a][16][17]
According toSpitzer Space Telescope's ExploreNEOs survey, the JapaneseAkari satellite, and NASA'sKeck Observatory,Ra-Shalom measures between 1.98 and 2.79 kilometers in diameter and its surface has analbedo between 0.080 and 0.177.[5][6][7][8][9][10][11][13] TheCollaborative Asteroid Lightcurve Link adopts an albedo of 0.082 and a diameter of 2.78 kilometers with anabsolute magnitude of 16.054.[12]
^abcdUsui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey".Publications of the Astronomical Society of Japan.63 (5):1117–1138.Bibcode:2011PASJ...63.1117U.doi:10.1093/pasj/63.5.1117. (online,AcuA catalog p. 153)
^Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs".Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221.doi:10.1007/978-3-642-01965-4.ISBN978-3-642-01964-7.
_Ra-Shalom.png)
.png)
