 Cerro Tololo Observatory image of2005 QN173 with a long, narrow tail (indicated with white arrows) on July 22, 2016 | |
| Discovery[1] | |
|---|---|
| Discovered by | NEAT |
| Discovery site | Palomar Observatory |
| Discovery date | August 29, 2005 |
| Designations | |
| 433P/(248370) 2005 QN173 | |
| 2005 QN173 | |
| main-belt · (outer)[2] | |
| Orbital characteristics[2] | |
| Epoch February 25, 2023 (JD 2460000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 8,055 d (22.05 yr) |
| Aphelion | 3.755 AU (561.7 Gm) |
| Perihelion | 2.374 AU (355.1 Gm) |
| 3.064 AU (458.4 Gm) | |
| Eccentricity | 0.2254 |
| 1,959 d (5.36 yr) | |
| 119.934° | |
| 0° 11m 1.494s / day | |
| Inclination | 0.068° |
| 174.334° | |
| 145.860° | |
| Physical characteristics[2] | |
| 3.599±0.214 km | |
| 0.054 | |
| C[3] | |
| 15.53[2] | |
(248370) 2005 QN173 is amain beltasteroid that undergoes recurrentcomet-like activity nearperihelion,[4][5] and is now designated comet433P/(248370) 2005 QN173.[6] This object was discovered on August 29, 2005 by theNear-Earth Asteroid Tracking program atPalomar Observatory.[1] It orbits in theouter mainasteroid belt[7] with anorbital period of 5.36 years, asemi-major axis of3.06 AU, and anorbital eccentricity of 0.225, bringing it as close as2.37 AU to theSun atperihelion. Theorbital plane is inclined at an angle of 0.068° to theecliptic.[2]
On July 7, 2021,2005 QN173 was found to be active by theAsteroid Terrestrial-impact Last Alert System survey.[6] Archival imagery showed it had been active during a previous perihelion passage,[8] dated July 22, 2016.[9] This indicates the activity is due to thesublimation of icyvolatiles,[6] as is common with comets.[9] At the time that activity was identified, the object displayed a long, dusty tail, much like a comet. Follow up observations found this tail extended more than9′ along its orbital plane.[7] By August 14, 2021, thecoma around thenucleus was fading, while the brightness of the tail remained roughly constant.[6]
This asteroid has amean diameter of3.6±0.2 km, with a low visualalbedo of0.054±0.012. Its colors are consistent with a darkC-typecarbonaceous asteroidtaxonomic classification, which is a class more commonly found in the outer main belt. Dust particles ejected from the object had very low velocities of about1 m/s. This suggests that the dust emission may have been assisted by rapid spin of the asteroid, which would lower theescape velocity.[3]
The asteroid will make its next perihelion passage on September 3, 2026, and it may become active by February 2026.[3]
