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4257 Ubasti, provisional designation 1987 QA, is a stony asteroid, classified as near-Earth object of the Apollo group and as Mars-crosser, approximately 1.5 kilometers in diameter. It was discovered by American astronomer Jean Mueller at the Palomar Observatory in California on 23 August 1987. The asteroid was named for Bastet – also known as Baast, Ubaste or Ubasti – the Egyptian goddess of cats.

Orbit and classification

Ubasti orbits the Sun at a distance of 0.9–2.4 AU once every 2 years and 1 month (772 days). Its orbit has an eccentricity of 0.47 and an inclination of 41° with respect to the ecliptic. Due to its high eccentricity, Ubasti is also a Mars-crossing asteroid. The body's observation arc begins with its official discovery observation, as no precoveries were taken and no prior identification had been made.

Close approaches

As a near-Earth object, Ubasti has a low Earth minimum orbital intersection distance of 0.1714 AU (25,600,000 km), which corresponds to 66.8 lunar distances (LD). This distance, however, is too large to make it a potentially hazardous asteroid (0.05 AU; less than 20 LD).

Physical characteristics

Ubasti is an assumed stony S-type asteroid.

Rotation period

As of 2017, no rotational lightcurve of Ubasti has been obtained and its rotation period remains unknown. However, the Lowell Observatory Near-Earth Asteroid Photometric Survey has measured the body's brightness variation caused by its rotation, which gave a maximum of 0.36 magnitude. This indicates that the body has a somewhat non-spherical shape.

Diameter and albedo

According to the survey carried out by the Japanese Akari satellite, Ubasti measures 1.30 kilometers in diameter and its surface has an albedo of 0.376, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.96 kilometers based on an absolute magnitude of 15.9.

Naming

This minor planet was named after Egyptian goddesses Bastet, who was originally the goddess of warfare, equated with the lioness war goddess, but later transformed into a major protector deity represented as a cat. The official naming citation was published by the Minor Planet Center on 21 November 1991 (M.P.C. 19336). The discoverer dedicated this asteroid to her beloved companion, Pepper Cat (1974–1991).

References

1. ^ "JPL Small-Body Database Browser: 4257 Ubasti (1987 QA)" (2016-08-30 last obs.). Jet Propulsion Laboratory. Retrieved 15 September 2017.
2. ^ Schmadel, Lutz D. (2007). "(4257) Ubasti". Dictionary of Minor Planet Names – (4257) Ubasti. Springer Berlin Heidelberg. p. 365. doi:10.1007/978-3-540-29925-7_4219. ISBN 978-3-540-00238-3.
3. ^ "4257 Ubasti (1987 QA)". Minor Planet Center. Retrieved 15 September 2017.
4. ^ Usui, 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)
5. ^ "LCDB Data for (4257) Ubasti". Asteroid Lightcurve Database (LCDB). Retrieved 15 September 2017.
6. Skiff, Brian A.; Bowell, Edward; Koehn, Bruce W.; Sanborn, Jason J.; McLelland, Kyle P.; Warner, Brian D. (July 2012). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2008 May through 2008 December". The Minor Planet Bulletin. 39 (3): 111–130. Bibcode:2012MPBu...39..111S. ISSN 1052-8091. Retrieved 15 September 2017.
7. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 15 September 2017.

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• 4257 Ubasti at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 4257 Ubasti at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 4257 Ubasti at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Apollo asteroids
• Discoveries by Jean Mueller
• Named minor planets
• Astronomical objects discovered in 1987