| Discovery[1] | |
|---|---|
| Discovered by | Perth Obs. |
| Discovery site | Perth Obs. |
| Discovery date | 1 August 1978 |
| Designations | |
| (4362) Carlisle | |
Named after | Albert Carlisle (Australianmeteorite hunter)[2] |
| 1978 PR4 · 1974 FM1 1984 EE1 | |
| main-belt · Flora [3][4] | |
| Orbital characteristics[5] | |
| Epoch 1 July 2021 (JD 2459396.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 68.88yr (25,158 d) |
| Aphelion | 2.4645AU |
| Perihelion | 2.0119 AU |
| 2.2382 AU | |
| Eccentricity | 0.1011 |
| 3.35 yr (1,223 d) | |
| 21.611° | |
| 0° 17m 39.84s / day | |
| Inclination | 4.7137° |
| 34.379° | |
| 171.93° | |
| Knownsatellites | 1[6] (>0.33 Ds/DpP: 1.804h) |
| Physical characteristics | |
| 2.63289±0.00007 h[10] | |
| S (assumed)[10] | |
| 13.16[1][5] | |
4362 Carlisle,provisional designation:1978 PR4, is a stonyFlora asteroid andbinary system from the inner regions of theasteroid belt. It was discovered on 1 August 1978, by staff members of thePerth Observatory at Bickley, Western Australia.[1] The asteroid measures approximately 5 kilometers (3.1 miles) in diameter, has a shortrotation period of 2.6 hours, and is likely spheroidal in shape. It was named in memory of Australianmeteorite hunterAlbert Carlisle (1917–1993).[2] In June 2021, the discovery of acompanion with an orbital period of 1.8 days and a diameter no less than a third of its primary, was announced.[6]
When applying the synthetichierarchical clustering method (HCM) byNesvorný,[3] or the 1995 HCM-analysis byZappalà,[4]Carlisle is a member of theFlora family (402), a giantasteroid family and the largest family of stony asteroids in the main-belt.[11]: 23 However, according to another HCM-analysis byMilani andKnežević (AstDys), it is abackground asteroid as this analysis does not recognize the Floraasteroid clan.[12]
Carlisle orbits the Sun in theinner main-belt at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,223 days;semi-major axis of 2.24 AU). Its orbit has aneccentricity of 0.10 and aninclination of 5° with respect to theecliptic.[5] The firstprecovery was taken atMount Wilson Observatory in 1952, extending the body'sobservation arc by 26 years prior to its official discovery at Bickley.[1]
Thisminor planet was named aftermeteorite hunterAlbert Carlisle (1917–1993), who lived in theAustralian Outback. During the course of half a century, he collected more than 9,000 of these rocky or metallic debris on theNullarbor Plain of Western Australia and was awarded theMedal of the Order of Australia for his scientific contribution in 1982.[2] The officialnaming citation was published by theMinor Planet Center on 29 November 1993 (M.P.C. 22829).[13]
Carlisle is an assumed stonyS-type asteroid, which is the dominantspectral type for members of theFlora family.[10]
Between March and June 2021, a rotationallightcurve ofCarlisle was obtained fromphotometric observations by an international collaboration of astronomers. Lightcurve analysis gave arotation period of2.63289±0.00007 hours with a low brightness variation of0.11magnitude, suggesting a nearly spheroidal shape (U=n.a.).[6][10][14]
The collaboration included the following astronomers and observatories: Vladimir Benishek atBelgrade Observatory (Serbia),Petr Pravec atOndřejov Observatory (Czech Republic),Julian Oey atBlue Mountains Observatory (Australia), Alessandro Marchini and Riccardo Papini of theAstronomical Observatory University of Siena (Italy),Frederick Pilcher atOrgan Mesa Observatory (USA-NM), Richard Durkee atShed of Science South Observatory (USA-TX),Vasilij Chiorny at Chuguev station of theKharkiv Observatory (Ukraine), R. Montaigut andArnaud Leroy atOPERA Observatory (France), and M. Deldem atLes Barres Observatory (France).[14]
The international collaboration also observedmutual occultation and eclipsing events that had an amplitude of 0.11 in magnitude. This revealed the presence of asatellite at least a third the size ofCarlisle, orbiting it once every1.804±0.001 days (or 43.3 hours) at an estimated average distance of 17 kilometers.[6][14]
According to the surveys carried out by NASA'sWide-field Infrared Survey Explorer and its subsequentNEOWISE mission,Carlisle measures5.20±0.23 and5.590±0.174 kilometers in diameter, based on a very highalbedo of0.412±0.064 and0.391±0.055, respectively.[7][8][9] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – taken from the Flora family's largest member and namesake, the asteroid8 Flora – and calculates a larger diameter of 6.5 kilometers.[10]
Photometric observations by an international collaboration that discovered a satellite in 2021, gave a secondary-to-primary diameter ratio (Ds/Dp) of at least 0.33.[14] This means, that the moon's size is at least 33% of that ofCarlisle's (the primary body). Based on the NEOWISE observations which gave an effective diameter of 5.59 km (3.5 mi), a lower diameter-limit for the moon of 1.75 km (1.1 mi) and an upper diameter-limit forCarlisle of 5.31 km (3.3 mi) can be calculated.[6]
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