259P/Garradd
 Comet 259P/Garradd in two different dates, one that was active (left) and one in which it appears inactive (right) | |
| Discovery[1] | |
|---|---|
| Discovered by | Gordon J. Garradd |
| Discovery site | Siding Spring Observatory |
| Discovery date | 2 September 2008 |
| Designations | |
| P/2008 R1 | |
| Garradd 4 | |
| Orbital characteristics[2][3] | |
| Epoch | 26 July 2017 (JD 2457960.5) |
| Observation arc | 9.05 years |
| Number of observations | 68 |
| Aphelion | 3.654 AU |
| Perihelion | 1.809 AU |
| Semi-major axis | 2.731 AU |
| Eccentricity | 0.33771 |
| Orbital period | 4.514 years |
| Inclination | 15.889° |
| 51.484° | |
| Argument of periapsis | 257.50° |
| Mean anomaly | 358.03° |
| Last perihelion | 8 February 2022 |
| Next perihelion | 11 August 2026 |
| TJupiter | 3.217 |
| Earth MOID | 0.858 AU |
| Jupiter MOID | 1.925 AU |
| Physical characteristics[4] | |
Mean radius | 0.30±0.02 km |
| 0.05 (assumed) | |
| Comet total magnitude (M1) | 13.7 |
| Comet nuclear magnitude (M2) | 18.9 |
259P/Garradd is a Jupiter-family comet and active asteroid with an orbital period of 4.5 years. It was discovered in images obtained on 2 September 2008 as part of the Siding Spring Survey by Gordon J. Garradd.[1][5]
Physical characteristics
[edit]The comet upon discovery had an apparent magnitude of 18.5 and a coma about 15 arcseconds across.[1] The comet dimmed by 1.5 magnitudes until mid November 2008. The spectrum of the comet during that period indicated a lack of gaseous emission lines and the mass loss rate was estimated to be less than 1.5 kg/s.[6] The comet was observed in 2011-12, when it was inactive, with the observations indicating an effective radius of about 0.3 kilometers assuming a geometric albedo of 0.05.[4][7]
The comet was observed to be active again during the 2017 perihelion, indicating that the source of activity is sublimation. The activity started to be detected when the comet was about 2 AU from the Sun, indicating that volatile ices are located deeper under the surface, as they have been probably more depleted due to the fact that it approaches closer to the Sun during perihelion than other active asteroids.[8]
Orbit
[edit]The orbit of the comet is unstable within a timescale of tens of millions years. It lies near the 3:8 orbital resonanse with Jupiter. It has a Jupiter Tisserand parameter of over three, indicating that it originates from the main asteroid belt instead of the Kuiper belt.[6] It does not belong to a known asteroid family.[9]
References
[edit]- ^ a b c G. J. Garradd; G. Sostero; P. Camilleri; et al. (1 September 2008). "Comet C/2008 R1 (Garradd)". IAU Circular. 8969 (1). Bibcode:2008IAUC.8969....1G. ISSN 0081-0304.
- ^ "259P/Garradd – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 20 July 2023.
- ^ "259P/Garradd Orbit". Minor Planet Center. Retrieved 14 June 2025.
- ^ a b E. M. MacLennan; H. H. Hsieh (2012). "The Nucleus of Main-Belt Comet 259P/Garradd". The Astrophysical Journal Letters. 758 (1): 3–9. arXiv:1209.3065. Bibcode:2012ApJ...758L...3M. doi:10.1088/2041-8205/758/1/L3.
- ^ B. G. Marsden (4 September 2008). "MPEC 2008-R22: Comet C/2024 G3 (ATLAS)". www.minorplanetcenter.net. Minor Planet Center. ISSN 1523-6714. Retrieved 6 September 2024.
- ^ a b D. C. Jewitt; B. Yang; N. Haghighipour (2009). "Main-Belt Comet P/2008 R1 (Garradd)". The Astronomical Journal. 137 (5): 4313–4321. arXiv:0902.4315. Bibcode:2009AJ....137.4313J. doi:10.1088/0004-6256/137/5/4313.
- ^ J. Kleyna; K. J. Meech; O. R. Hainaut (2012). "Faint moving object detection, and the Low Signal-to-Noise recovery of Main Belt comet P/2008 R1 Garradd". Publications of the Astronomical Society of the Pacific. 124 (920): 1083–1089. arXiv:1209.3833. Bibcode:2012PASP..124.1083K. doi:10.1086/668253.
- ^ H. H. Hsieh; M. Ishiguro; M. M. Knight; et al. (2021). "The Reactivation of Main-belt Comet 259P/Garradd (P/2008 R1)". The Planetary Science Journal. 2 (2): 62–72. arXiv:2102.06290. Bibcode:2021PSJ.....2...62H. doi:10.3847/PSJ/abe59d.
- ^ H. H. Hsieh; B. Novaković; Y. Kim; R. Brasser (2018). "Asteroid Family Associations of Active Asteroids". The Astronomical Journal. 155 (2): 96–118. arXiv:1801.01152. Bibcode:2018AJ....155...96H. doi:10.3847/1538-3881/aaa5a2.
External links
[edit]- 259P/Garradd at the JPL Small-Body Database
- 259P/Garradd at Seiichi Yoshida's website
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