Astronomy:4257 Ubasti
| Discovery [1] | |
|---|---|
| Discovered by | J. E. Mueller |
| Discovery site | Palomar Obs. |
| Discovery date | 23 August 1987 |
| Designations | |
| (4257) Ubasti | |
| Named after | Bastet [2] (Egyptian goddess of cats) |
| 1987 QA | |
| Minor planet category | NEO · Apollo [1][3] Mars-crosser |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 29.02 yr (10,600 days) |
| |{{{apsis}}}|helion}} | 2.4183 AU |
| |{{{apsis}}}|helion}} | 0.8759 AU |
| 1.6471 AU | |
| Eccentricity | 0.4682 |
| Orbital period | 2.11 yr (772 days) |
| Mean anomaly | 28.670° |
| Mean motion | 0° 27m 58.32s / day |
| Inclination | 40.716° |
| Longitude of ascending node | 169.22° |
| 278.92° | |
| Earth MOID | 0.1714 AU · 66.8 LD |
| Physical characteristics | |
| Dimensions | 1.30±0.09 km[4] 1.96 km (calculated)[5] |
| Geometric albedo | 0.20 (assumed)[5] 0.376±0.053[4] |
| S [5] | |
| Absolute magnitude (H) | 15.9[1][5] · 16.20[4] |
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.[3] The asteroid was named for Bastet – also known as Baast, Ubaste or Ubasti – the Egyptian goddess of cats.[2]
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.[1] 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.[3]
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).[1]
Physical characteristics
Ubasti is an assumed stony S-type asteroid.[5]
Rotation period
As of 2017, no rotational lightcurve of Ubasti has been obtained and its rotation period remains unknown.[5] 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.[6]
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,[4] 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.[5]
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.[2] The official naming citation was published by the Minor Planet Center on 21 November 1991 (M.P.C. 19336).[7] The discoverer dedicated this asteroid to her beloved companion, Pepper Cat (1974–1991).[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "JPL Small-Body Database Browser: 4257 Ubasti (1987 QA)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004257.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 3.0 3.1 3.2 "4257 Ubasti (1987 QA)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=4257.
- ↑ 4.0 4.1 4.2 4.3 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. doi:10.1093/pasj/63.5.1117. Bibcode: 2011PASJ...63.1117U. (online, AcuA catalog p. 153)
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "LCDB Data for (4257) Ubasti". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4257%7CUbasti.
- ↑ 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. ISSN 1052-8091. Bibcode: 2012MPBu...39..111S. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012MPBu...39..111S. Retrieved 15 September 2017.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.
External links
- Asteroid Lightcurve Database (LCDB), query form (info )
- 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
- Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
- 4257 Ubasti at ESA–space situational awareness
- 4257 Ubasti at the JPL Small-Body Database
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