4257 Ubasti

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]

4257 Ubasti
Discovery [1]
Discovered byJ. E. Mueller
Discovery sitePalomar Obs.
Discovery date23 August 1987
Designations
(4257) Ubasti
Named after
Bastet [2]
(Egyptian goddess of cats)
1987 QA
NEO · Apollo [1][3]
Mars-crosser
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc29.02 yr (10,600 days)
Aphelion2.4183 AU
Perihelion0.8759 AU
1.6471 AU
Eccentricity0.4682
2.11 yr (772 days)
28.670°
0° 27m 58.32s / day
Inclination40.716°
169.22°
278.92°
Earth MOID0.1714 AU · 66.8 LD
Physical characteristics
Dimensions1.30±0.09 km[4]
1.96 km (calculated)[5]
0.20 (assumed)[5]
0.376±0.053[4]
S [5]
15.9[1][5] · 16.20[4]

    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. "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. Retrieved 17 October 2019. (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.
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