(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 29 August 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]
| Cerro Tololo Observatory image of 2005 QN173 with a long, narrow tail (indicated with white arrows) on 22 July 2016 | |
| Discovery[1] | |
|---|---|
| Discovered by | NEAT |
| Discovery site | Palomar Observatory |
| Discovery date | 29 August 2005 |
| Designations | |
| 433P/(248370) 2005 QN173 | |
| 2005 QN173 | |
| main-belt · (outer)[2] | |
| Orbital characteristics[2] | |
| Epoch 25 February 2023 (JD 2460000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 22.05 yr (8,055 days) |
| Aphelion | 3.755 AU |
| Perihelion | 2.374 AU |
| 3.064 | |
| Eccentricity | 0.2254 |
| 5.36 yr (1,959 d) | |
| 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] | |
On 7 July 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 22 July 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 14 August 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 3 September 2026, and it may become active by February 2026.[3]
- ^ a b “(248370) = 2005 QN173”. Minor Planet Center. Retrieved 18 February 2023.
- ^ a b c d e “JPL Small-Body Database Browser: 248370 (2005 QN173)” (2022-12-17). Jet Propulsion Laboratory. Retrieved 18 February 2023.
- ^ a b c Hsieh, Henry H.; et al. (November 2021), “Physical Characterization of Main-belt Comet (248370) 2005 QN173”, The Astrophysical Journal Letters, 922 (1): L9, arXiv:2109.14822, Bibcode:2021ApJ…922L…9H, doi:10.3847/2041-8213/ac2c62, L9.
- ^ Planetary Science Institute (4 October 2021), “Is new finding an asteroid or a comet? It’s both”, phys.org, retrieved 18 February 2023.
- ^ Jefferson, Ron (6 October 2021), “New Space Rock Hybrid Discovered Near Sun; Confirmed as Both Comet and Asteroid”, The Science Times, retrieved 19 February 2023.
- ^ a b c d Lister, Tim; et al. (July 2022), “The LCO Outbursting Objects Key Project: Overview and Year 1 Status”, The Planetary Science Journal, 3 (7): 173, arXiv:2206.09028, Bibcode:2022PSJ…..3..173L, doi:10.3847/PSJ/ac7a31, 173.
- ^ a b Hsieh, Henry; et al. (October 2021), “The Nucleus and Dust Tail of Active Asteroid (248370) 2005 QN173”, Bulletin of the American Astronomical Society, 53 (7), Bibcode:2021DPS….5311004H, 2021n7i110p04.
- ^ Chandler, C. O.; et al. (26 July 2021), Green, Daniel W. E. (ed.), “(248370) 2005 QN_173”, Central Bureau for Astronomical Telegrams, 5005, retrieved 17 February 2023.
- ^ a b Chandler, Colin Orion; et al. (November 2021), “Recurrent Activity from Active Asteroid (248370) 2005 QN173: A Main-belt Comet”, The Astrophysical Journal Letters, 922 (1): L8, arXiv:2111.06405, Bibcode:2021ApJ…922L…8C, doi:10.3847/2041-8213/ac365b, L8.
- Masi, Gianluca (29 October 2021), “Comet 433P = Asteroid (248370) 2005 QN173 and its tail: new images – 12 Sept. and 27 Oct. 2021”, The Virtual Telescope Project 2.0, retrieved 19 February 2023.
- Olason, Mike (8 October 2021), “Comet 433P”, Sky & Telescope, AAS Sky Publishing, LLC, retrieved 19 February 2023.
- Ivanova, Oleksandra; et al. (September 2022), “Dust environment of active asteroid (248370) 2005 QN173”, 16th Europlanet Science Congress 2022, held 18–23 September 2022 at Palacio de Congresos de Granada, Spain, Bibcode:2022EPSC…16..203I, doi:10.5194/epsc2022-203, EPSC2022-203.