 Cerro Tololo Observatory image of 2005 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 a main belt asteroid that undergoes recurrent comet-like activity near perihelion, [4] [5] and is now designated comet 433P/(248370) 2005 QN173. [6] This object was discovered on August 29, 2005 by the Near-Earth Asteroid Tracking program at Palomar Observatory. [1] It orbits in the outer main asteroid belt [7] with an orbital period of 5.36 years, a semi-major axis of 3.06 AU , and an orbital eccentricity of 0.225, bringing it as close as 2.37 AU to the Sun at perihelion. The orbital plane is inclined at an angle of 0.068° to the ecliptic. [2]
On July 7, 2021, 2005 QN173 was found to be active by the Asteroid 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 the sublimation of icy volatiles, [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 than 9′ along its orbital plane. [7] By August 14, 2021, the coma around the nucleus was fading, while the brightness of the tail remained roughly constant. [6]
This asteroid has a mean diameter of 3.6±0.2 km, with a low visual albedo of 0.054±0.012. Its colors are consistent with a dark C-type carbonaceous asteroid taxonomic classification, which is a class more commonly found in the outer main belt. Dust particles ejected from the object had very low velocities of about 1 m/s. This suggests that the dust emission may have been assisted by rapid spin of the asteroid, which would lower the escape velocity. [3]
The asteroid will make its next perihelion passage on September 3, 2026, and it may become active by February 2026. [3]
