 Alconrad and its satellite imaged by theHubble Space Telescope from November to December 2005 | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Korlević M. Jurić |
| Discovery site | Višnjan Obs. |
| Discovery date | 11 October 1999 |
| Designations | |
| (22899) Alconrad | |
Named after | Albert R. Conrad (AmericanAO-expert)[2] |
| 1999 TO14 · 1998 ML48 | |
| main-belt · Koronis[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 21.57 yr (7,877 days) |
| Aphelion | 3.0790AU |
| Perihelion | 2.6094 AU |
| 2.8442 AU | |
| Eccentricity | 0.0825 |
| 4.80yr (1,752 days) | |
| 300.93° | |
| 0° 12m 19.8s / day | |
| Inclination | 2.8820° |
| 136.00° | |
| 220.62° | |
| Knownsatellites | 1[4][a] |
| Physical characteristics | |
| Dimensions | 4.5 km[4] 4.94 km(calculated)[3] 5.682±0.471 km[5][6] |
| 4.03±0.03h[7] 5.0206±0.0029 h[8] | |
| 0.181±0.029[5][6] 0.21[4] 0.24(assumed)[3] | |
| S[3] | |
| 13.677±0.004(R)[8] · 13.7[3][5] · 13.8[1] · 13.96±0.25[9] | |
22899 Alconrad (provisional designation1999 TO14) is a Koronianasteroid andbinary system from the outer region of theasteroid belt, approximately 5 kilometers in diameter. It was discovered on 11 October 1999, by Croatian astronomersKorado Korlević andMario Jurić at theVišnjan Observatory, Croatia.[2]
When itsminor-planet moon was discovered in 2003, it was the smallest known main-belt asteroid to possess a satellite. It was later named after American astronomerAlbert R. Conrad.
Alconrad belongs to theKoronis family, a collisional group ofstony asteroids consisting of a few hundred known bodies with nearlyecliptical orbits. It orbits the Sun in theouter main-belt at a distance of 2.6–3.1 AU once every 4 years and 10 months (1,752 days). Its orbit has aneccentricity of 0.08 and aninclination of 3° with respect to the ecliptic.[1] The body'sobservation arc begins 5 years prior to its official discovery observation, with aprecovery taken bySteward Observatory'sSpacewatch program in October 1994.[2]
In December 2009, a rotationallightcurve of Alconrad was obtained from photometric observations at the ground-basedWise Observatory in Mitzpe Ramon, Israel. Lightcurve analysis gave arotation period of4.03 hours with a brightness variation of0.19magnitude (U=2).[7]
In October 2013, photometric observations by astronomers in the R-band at thePalomar Transient Factory in California gave a period of5.0206 with an amplitude of0.14 magnitude (U=2).[8]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, Alconrad measures 5.7 kilometers in diameter and its surface has analbedo of 0.18,[5][6] while heCollaborative Asteroid Lightcurve Link assumes a standard albedo for members of the Koronis family of 0.24, and calculates a diameter of 4.9 kilometers with anabsolute magnitude of 13.7.[3]
Thisminor planet was named in honor of American astronomer Albert R. Conrad (born 1953) who worked at various observatories in the United States. Expert in and developer ofadaptive optics, he has studied thenatural satellites of the Solar System for their shape and topography, and co-discovered manyasteroid moons in the process.[2] The official naming citation was published by theMinor Planet Center on 20 June 2016 (M.P.C. 100606).[10]
In October 2003, researchers atSouthwest Research Institute using theHubble Space Telescope discovered a moon orbiting Alconrad, which was later namedJuliekaibarreto.[11] They calculated a diameter of 4.5 kilometers for the primary, based on an assumed albedo of 0.21. The researchers also measured a large angular separation of 0".14 between Alconrad and its moon. This is equivalent to a distance of 170 kilometers,[4] or 182 kilometers, when using a/Rp ratio of 81.[7] Based on a difference in magnitude of 2.5, the satellite measures 1 to 1.5 kilometers in diameter.[4][7] It was named after Julie Kai Barreto, Albert Conrad's wife.[11]
When the binary nature of Alconrad was discovered in 2003, it was the smallest binary asteroid known at the time.[4][a] Since then, other binaries with a smaller primary have been discovered such as, for example,4868 Knushevia (1.5 km) in 2015, and8026 Johnmckay (1.7 km) in 2010.
