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Active asteroid

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Asteroid596 Scheiladisplaying a comet-like appearance on 12 December 2010
Dust ejecta and tail from the aftermath of theDouble Asteroid Redirection Test's impact on theasteroid moonDimorphos,as seen by theSouthern Astrophysical Research Telescopein 2022

Active asteroidsaresmall Solar System bodiesthat haveasteroid-like orbits but showcomet-like visual characteristics.[1]That is, they show acoma,tail,or other visual evidence of mass-loss (like a comet), but their orbits remain withinJupiter's orbit (like an asteroid).[2][3]These bodies were originally designatedmain-belt comets(MBCs) in 2006 by astronomersDavid JewittandHenry Hsieh,but this name implies they are necessarily icy in composition like a comet and that they only exist within themain-belt,whereas the growing population of active asteroids shows that this is not always the case.[2][4][5]

The first active asteroid discovered is7968 Elst–Pizarro.It was discovered (as an asteroid) in 1979 but then was found to have a tail byEric Elstand Guido Pizarro in 1996 and given the cometary designation 133P/Elst-Pizarro.[2][6]

Orbits

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Unlikecomets,which spend most of their orbit at Jupiter-like or greater distances from the Sun, active asteroids follow orbits within the orbit ofJupiterthat are often indistinguishable from the orbits of standardasteroids.Jewittdefines active asteroids as those bodies that, in addition to having visual evidence of mass loss, have an orbit with:[3]

Jewitt chooses 3.08 as the Tisserand parameter to separate asteroids and comets instead of 3.0 (the Tisserand parameter of Jupiter itself) to avoid ambiguous cases caused by the realSolar Systemdeviating from an idealizedrestricted three-body problem.[3]

The first three identified active asteroids all orbit within the outer part of theasteroid belt.[7]

Activity

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Disintegration of asteroidP/2013 R3observed by theHubble Space Telescope(6 March 2014).[8][9]

Some active asteroids display a cometary dust tail only for a part of their orbit nearperihelion.This strongly suggests that volatiles at their surfaces are sublimating, driving off the dust.[10]Activity in133P/Elst–Pizarrois recurrent, having been observed at each of the last three perihelia.[2]The activity persists for a month or several[7]out of each 5-6 year orbit, and is presumably due to ice being uncovered by minor impacts in the last 100 to 1000 years.[7]These impacts are suspected to excavate these subsurface pockets ofvolatilematerial helping to expose them tosolar radiation.[7]

When discovered in January 2010,P/2010 A2 (LINEAR)was initially given a cometary designation and thought to be showing comet-like sublimation,[11]but P/2010 A2 is now thought to be the remnant of an asteroid-on-asteroid impact.[12][13]Observations of596 Scheilaindicated that large amounts of dust were kicked up by the impact of another asteroid of approximately 35 meters in diameter.

P/2013 R3

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P/2013 R3 (Catalina–PanSTARRS) was discovered independently by two observers byRichard E. Hillusing the Catalina Sky Survey's 0.68-m Schmidt telescope and byBryce T. Bolinusing the 1.8-m Pan-STARRS1 telescope on Haleakala.[14]The discovery images taken byPan-STARRS1showed the appearance of two distinct sources within 3 "of each other combined with a tail enveloping both sources. In October 2013, follow-up observations of P/2013 R3, taken with the 10.4 mGran Telescopio Canariason the island ofLa Palma,showed that this comet was breaking apart.[15]Inspection of the stacked CCD images obtained on October 11 and 12 showed that the main-belt comet presented a central bright condensation that was accompanied on its movement by three more fragments, A, B, C. The brightest A fragment was also detected at the reported position in CCD images obtained at the 1.52 m telescope of theSierra Nevada Observatoryin Granada on October 12.[15]

NASAreported on a series of images taken by theHubble Space Telescopebetween October 29, 2013, and January 14, 2014, that show the increasing separation of the four main bodies.[16]TheYarkovsky–O'Keefe–Radzievskii–Paddack effect,caused by sunlight, increased the spin rate until thecentrifugal forcecaused therubble pileto separate.[16]

Dimorphos

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By smashing into the asteroid moon of thebinary asteroid65803 Didymos,NASA'sDouble Asteroid Redirection Testspacecraft made Dimorphos an active asteroid. Scientists had proposed that some active asteroids are the result of impact events, but no one had ever observed the activation of an asteroid. The DART mission activated Dimorphos under precisely known and carefully observed impact conditions, enabling the detailed study of the formation of an active asteroid for the first time.[17][18]Observations show that Dimorphos lost approximately 1 million kilograms after the collision.[19]Impact produced a dust plume that temporarily brightened the Didymos system and developed a 10,000-kilometer (6,200 mi)-longdust tailthat persisted for several months.[20][21][22]The DART impact is predicted to have caused global resurfacing and deformation of Dimorphos's shape, leaving animpact craterseveral tens of meters in diameter.[23][24][25]The impact has likely sent Dimorphos into achaoticallytumblingrotation that will subject the moon to irregulartidal forcesby Didymos before it will eventually return to atidally lockedstate within several decades.[26][27][28]

Composition

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Some active asteroids show signs that they are icy in composition like a traditional comet, while others are known to be rocky like an asteroid. It has been hypothesized that main-belt comets may have been the source of Earth's water, because the deuterium–hydrogen ratio of Earth's oceans is too low for classical comets to have been the principal source.[29]European scientists have proposed a sample-return mission from a MBC calledCarolineto analyse the content of volatiles and collect dust samples.[10]

List

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Identified members of this morphology class (TJup>3.08) include:[30]: 17 

Name Semi-major axis
(AU)
Perihelion
(AU)
Eccentricity TJup Orbital
class
Diameter
(km)
Rotation
period
(hr)
Cause Activity
discovery
year
Recurrent?
1 Ceres 2.766 2.550 0.078 3.310 main-belt (middle) 939.4 9.07 Water sublimation[3] 2014
493 Griseldis 3.116 2.568 0.176 3.140 main-belt (outer) 41.56 51.94 Impact[31] 2015
596 Scheila 2.929 2.45 0.163 3.209 main-belt (outer) 159.72 15.85 Impact[32][33][34] 2011
2201 Oljato 2.174 0.624 0.713 3.299 NEO (Apollo) 1.8 >26 Sublimation[35] 1984
3200 Phaethon 1.271 0.140 0.890 4.510 NEO (Apollo) 6.26 3.60 Thermal fracturing,dehydration cracking,and/or rotational disintegration[36] 2010
6478 Gault 2.305 1.860 0.193 3.461 main-belt (inner) 5.6 2.49 Rotational disintegration[37][38][39] 2019
(62412) 2000 SY178 3.159 2.909 0.079 3.197 main-belt (outer) 10.38 3.33 Rotational disintegration[40] 2014
65803 Didymos/Dimorphos 1.643 1.013 0.383 4.204 NEO (Apollo) 0.77 / 0.15 2.26 Human-caused impact 2022
101955 Bennu 1.126 0.896 0.204 5.525 NEO (Apollo) 0.48 4.29 (unknown)[30]: 22 
Electrostatic lofting, impacts, thermal fracturing, or dehydration cracking
2019
(588045) 2007 FZ18 3.176 2.783 0.124 3.188 main-belt (outer) 2023
2002 CW116 2.690 2.068 0.231 3.319 main-belt (middle) 0.5 2024
2008 BJ22 3.071 2.943 0.042 3.199 main-belt (outer) <0.4 2022
2010 LH15 2.744 1.770 0.355 3.230 main-belt (middle) 1.483 2023
2015 BC566 3.062 2.957 0.034 3.201 main-belt (outer) 2023
2015 FW412 2.765 2.319 0.161 3.280 main-belt (middle) 2023
2015 VA108 3.128 2.451 0.217 3.160 main-belt (outer) 2023
2023 JN16 2.696 2.300 0.147 3.351 main-belt (middle) 2023
107P/4015 Wilson–Harrington 2.625 0.966 0.632 3.082 NEO (Apollo) 6.92 7.15 Sublimation[41][42] 1949
133P/7968 Elst–Pizarro 3.165 2.668 0.157 3.184 main-belt (outer) 3.8 3.47 Sublimation/rotational disintegration[43][44] 1996
176P/118401 LINEAR 3.194 2.578 0.193 3.167 main-belt (outer) 4.0 22.23 Sublimation[45] 2005
233P/La Sagra(P/2009 WJ50) 3.033 1.786 0.411 3.081 main-belt (outer) 3.0 2010
238P/Read(P/2005 U1) 3.162 2.362 0.253 3.153 main-belt (outer) 0.8 Sublimation[46] 2005
259P/Garradd(P/2008 R1) 2.727 1.794 0.342 3.217 main-belt (middle) 0.60 Sublimation[47] 2008
288P/(300163) 2006 VW139 3.051 2.438 0.201 3.203 main-belt (outer) 1.8 / 1.2 Sublimation[48] 2011
311P/PanSTARRS(P/2013 P5) 2.189 1.935 0.116 3.660 main-belt (inner) 0.4 >5.4 Rotational disintegration[49][50][51] 2013
313P/Gibbs(P/2003 S10) 3.154 2.391 0.242 3.133 main-belt (outer) 2.0 Sublimation[52] 2003
324P/La Sagra(P/2010 R2) 3.098 2.621 0.154 3.099 main-belt (outer) 1.1 Sublimation[53] 2010
331P/Gibbs(P/2012 F5) 3.005 2.879 0.042 3.228 main-belt (outer) 3.54 3.24 Rotational disintegration[54][55] 2012
354P/LINEAR(P/2010 A2) 2.290 2.004 0.125 3.583 main-belt (inner) 0.12 11.36 Impact[56] 2010
358P/PanSTARRS (P/2012 T1) 3.155 2.410 0.236 3.134 main-belt (outer) 0.64 Sublimation[57] 2012
426P/PanSTARRS (P/2019 A7) 3.188 2.675 0.161 3.103 main-belt (outer) 2.4 2019
427P/ATLAS (P/2017 S5) 3.171 2.178 0.313 3.092 main-belt (outer) 0.90 1.4 Sublimation/rotational disintegration[58] 2017
432P/PanSTARRS (P/2021 N4) 3.045 2.302 0.244 3.170 main-belt (outer) <1.4 2021
433P/(248370) 2005 QN173 3.067 2.374 0.226 3.192 main-belt (outer) 3.2 Sublimation/rotational disintegration 2021
435P/PanSTARRS (P/2021 T3) 3.018 2.056 0.319 3.090 main-belt (outer) 2021
455P/PanSTARRS (P/2021 S9) 3.156 2.193 0.305 3.087 main-belt (outer) <1.6 2017
456P/PanSTARRS (P/2021 L4) 3.165 2.788 0.119 3.125 main-belt (outer) <4.4 2021
457P/2020 O1 (Lemmon–PanSTARRS) 2.647 2.329 0.120 3.376 main-belt (middle) 0.84 1.67 Sublimation/rotational disintegration[59] 2020
P/2013 R3 (Catalina–PanSTARRS) 3.033 2.205 0.273 3.184 main-belt (outer) ~0.4 Sublimation/rotational disintegration[60] 2013
P/2015 X6 (PanSTARRS) 2.755 2.287 0.170 3.318 main-belt (middle) <1.4 Sublimation[61] 2015
P/2016 G1 (PanSTARRS) 2.583 2.041 0.210 3.367 main-belt (middle) <0.8 Impact[62] 2016
P/2016 J1-A/B (PanSTARRS) 3.172 2.449 0.228 3.113 main-belt (outer) <1.8 / <0.8 Sublimation[63] 2016
P/2018 P3 (PanSTARRS) 3.007 1.756 0.416 3.096 main-belt (outer) <1.2 Sublimation 2018
P/2019 A3 (PanSTARRS) 3.147 2.313 0.265 3.099 main-belt (outer) <0.8 2019
P/2019 A4 (PanSTARRS) 2.614 2.379 0.090 3.365 main-belt (middle) 0.34 2019
P/2021 A5 (PanSTARRS) 3.047 2.620 0.140 3.147 main-belt (outer) 0.30 Sublimation 2021
P/2021 R8 (Sheppard) 3.019 2.131 0.294 3.179 main-belt (outer) 2021
P/2022 R5 (PanSTARRS) 3.071 2.470 0.196 3.148 main-belt (outer) 2022
P/2023 S4 (Hogan) 3.134 2.542 0.189 3.185 main-belt (outer) 2023
P/2024 L4 (Rankin) 2.231 0.672 0.699 3.255 NEO (apollo) <0.4 Rotational disintegration? 2024

Exploration

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Asteroid101955 Bennuseen ejecting particles on January 6, 2019, in images taken by theOSIRIS-RExspacecraft

Castaliais a proposed mission concept for a robotic spacecraft to explore133P/Elst–Pizarroand make the firstin situmeasurements of water in the asteroid belt, and thus, help solve the mystery of the origin of Earth's water.[64]The lead is Colin Snodgrass, fromThe Open Universityin the UK.Castaliawas proposed in 2015 and 2016 to theEuropean Space Agencywithin theCosmic Vision programmemissions M4 and M5, but it was not selected. The team continues to mature the mission concept and science objectives.[64]Because of the construction time required and orbital dynamics, a launch date of October 2028 was proposed.[64]

On January 6, 2019, theOSIRIS-RExmission first observed episodes of particle ejection from101955 Bennushortly after entering orbit around thenear-Earth asteroid,leading it to be newly classified as an active asteroid and marking the first time that asteroid activity had been observed up close by a spacecraft. It has since observed at least 10 other such events.[4]The scale of these observed mass loss events is much smaller than those previously observed at other active asteroids by telescopes, indicating that there is a continuum of mass loss event magnitudes at active asteroids.[65]

See also

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References

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  1. ^Andrews, Robin George (18 November 2022)."The Mysterious Comets That Hide in the Asteroid Belt - Comets normally fly in from the far reaches of space. Yet astronomers have found them seemingly misplaced in the asteroid belt. Why are they there?".The New York Times.Retrieved18 November2022.
  2. ^abcdDavid Jewitt."The Active Asteroids".UCLA,Department of Earth and Space Sciences.Retrieved2020-01-26.
  3. ^abcdJewitt, David; Hsieh, Henry; Agarwal, Jessica (2015)."The Active Asteroids"(PDF).In Michel, P.; et al. (eds.).Asteroids IV.University of Arizona.pp. 221–241.arXiv:1502.02361.Bibcode:2015aste.book..221J.doi:10.2458/azu_uapress_9780816532131-ch012.ISBN9780816532131.S2CID119209764.Retrieved2020-01-30.
  4. ^abChang, Kenneth; Stirone, Shannon (19 March 2019)."The Asteroid Was Shooting Rocks Into Space. 'Were We Safe in Orbit?' - NASA's Osiris-Rex and Japan's Hayabusa2 spacecraft reached the space rocks they are surveying last year, and scientists from both teams announced early findings on Tuesday (03/19/2019)".The New York Times.Retrieved21 March2019.
  5. ^"Hubble Observes Six Tails from an Unusual Asteroid".Space Telescope Science Institute (STScI), official YouTube channel for the Hubble Space Telescope.Archivedfrom the original on 2021-12-22.Retrieved2014-11-15.
  6. ^Hsieh, Henry (January 20, 2004)."133P/Elst-Pizarro".UH Institute for Astronomy. Archived fromthe originalon 26 October 2011.Retrieved22 June2012.
  7. ^abcdHenry H. Hsieh (May 2010)."Main Belt Comets".Hawaii. Archived fromthe originalon 2011-08-06.Retrieved2010-12-15.(older 2010 site)Archived2009-08-10 at theWayback Machine
  8. ^Harrington, J.D.; Villard, Ray (6 March 2014)."RELEASE 14-060 NASA's Hubble Telescope Witnesses Asteroid's Mysterious Disintegration".NASA.Retrieved6 March2014.
  9. ^"Hubble witnesses an asteroid mysteriously disintegrating".ESA / HUBBLE.Retrieved12 March2014.
  10. ^abThe proposed Caroline ESA M3 mission to a Main Belt Comet.Geraint H. Jones, Jessica Agarwal, Neil Bowles, Mark Burchell, Andrew J. Coates, Alan Fitzsimmons, Amara Graps, Henry H. Hsieh, Carey M. Lisse, Stephen C. Lowry, Adam Masters, Colin Snodgrass, Cecilia Tubiana.Advances in Space Research.25 February 2018.doi:10.1016/j.asr.2018.02.032
  11. ^MPEC 2010-A51: COMET P/2010 A2 (LINEAR)
  12. ^Jewitt, David; Weaver, Harold; Agarwal, Jessica; Mutchler, Max; Drahus, Michal (2010). "A recent disruption of the main-belt asteroid P/2010?A2".Nature.467(7317): 817–9.Bibcode:2010Natur.467..817J.doi:10.1038/nature09456.PMID20944743.S2CID205222567.
  13. ^Snodgrass, Colin; Tubiana, Cecilia; Vincent, Jean-Baptiste; Sierks, Holger; Hviid, Stubbe; Moissl, Richard; Boehnhardt, Hermann; Barbieri, Cesare; et al. (2010). "A collision in 2009 as the origin of the debris trail of asteroid P/2010?A2".Nature.467(7317): 814–6.arXiv:1010.2883.Bibcode:2010Natur.467..814S.doi:10.1038/nature09453.PMID20944742.S2CID4330570.
  14. ^Hill, R; Bolin, B; Kleyna, J; Denneau, L; Wainscoat, R; Micheli, M; Armstrong, J; Molina, M; Sato, H (2013)."CBET #3658: COMET P/2013 R3 (CATALINA-PANSTARRS)".Central Bureau Electronic Telegrams.3658.Central Bureau for Astronomical Telegrams:1.Bibcode:2013CBET.3658....1H.Retrieved27 September2013.
  15. ^abLicandro, Javier."Main Belt Comet P/2013 R3 is breaking apart".IAC Press Release.Retrieved17 October2013.
  16. ^ab"Hubble Witnesses Asteroid's Mysterious Disintegration | Science Mission Directorate".
  17. ^Furfaro, Emily (28 February 2023)."NASA's DART Data Validates Kinetic Impact as Planetary Defense Method".NASA.Retrieved9 March2023.Public DomainThis article incorporates text from this source, which is in thepublic domain.
  18. ^Li, Jian-Yang; Hirabayashi, Masatoshi; Farnham, Tony L.; et al. (1 March 2023)."Ejecta from the DART-produced active asteroid Dimorphos".Nature.616(7957): 452–456.arXiv:2303.01700.Bibcode:2023Natur.616..452L.doi:10.1038/s41586-023-05811-4.ISSN1476-4687.PMC10115637.PMID36858074.S2CID257282549.
  19. ^Witze, Alexandra (1 March 2023)."Asteroid lost 1 million kilograms after collision with DART spacecraft".Nature.615(7951): 195.doi:10.1038/d41586-023-00601-4.PMID36859675.S2CID257282080.Retrieved9 March2023.
  20. ^Blue, Charles (3 October 2022)."SOAR Telescope Catches Dimorphos's Expanding Comet-like Tail After DART Impact".NOIRLab.Retrieved4 February2023.
  21. ^Merzdorf, Jessica (15 December 2022)."Early Results from NASA's DART Mission".NASA.Retrieved4 February2023.
  22. ^Li, Jian-Yang; Hirabayashi, Masatoshi; Farnham, Tony; Knight, Matthew; Tancredi, Gonzalo; Moreno, Fernando; et al. (March 2022)."Ejecta from the DART-produced active asteroid Dimorphos"(PDF).Nature.616(7957): 452–456.arXiv:2303.01700.Bibcode:2023Natur.616..452L.doi:10.1038/s41586-023-05811-4.PMC10115637.PMID36858074.S2CID257282549.
  23. ^Raducan, Sabina D.; Martin, Jutzi (July 2022)."Global-scale Reshaping and Resurfacing of Asteroids by Small-scale Impacts, with Applications to the DART and Hera Missions".The Planetary Science Journal.3(6): 15.Bibcode:2022PSJ.....3..128R.doi:10.3847/PSJ/ac67a7.S2CID249268810.128.
  24. ^Nakano, Ryota; Hirabayashi, Masatoshi; Brozovic, M.; Nolan, M. C.; Ostro, S. J.; Margot, J. L.; et al. (July 2022)."NASA's Double Asteroid Redirection Test (DART): Mutual Orbital Period Change Due to Reshaping in the Near-Earth Binary Asteroid System (65803) Didymos".The Planetary Science Journal.3(7): 16.Bibcode:2022PSJ.....3..148N.doi:10.3847/PSJ/ac7566.hdl:11311/1223308.S2CID250327233.148.
  25. ^Raducan, S. D.; Jutzi, M.; Zhang, Y.; Cheng, A. F.; Collins, G. S.; Davison, T. M.; et al. (March 2023).Low Strength of Asteroid Dimorphos As Demonstrated by the Dart Impact(PDF).54th Lunar and Planetary Science Conference 2023. Lunar and Planetary Institute.Retrieved4 February2023.
  26. ^Agrusa, Harrison F.; Gkolias, Ioannis; Tsiganis, Kleomenis; Richardson, Derek C.; Meyer, Alex J.; Scheeres, Daniel J.; et al. (December 2021). "The excited spin state of Dimorphos resulting from the DART impact".Icarus.370:39.arXiv:2107.07996.Bibcode:2021Icar..37014624A.doi:10.1016/j.icarus.2021.114624.S2CID236033921.114624.
  27. ^Richardson, Derek C.; Agrusa, Harrison F.; Barbee, Brent; Bottke, William F.; Cheng, Andrew F.; Eggl, Siegfried; et al. (July 2022)."Predictions for the Dynamical States of the Didymos System before and after the Planned DART Impact".The Planetary Science Journal.3(7): 23.arXiv:2207.06998.Bibcode:2022PSJ.....3..157R.doi:10.3847/PSJ/ac76c9.S2CID249268465.157.
  28. ^Meyer, A. J.; Noiset, G.; Karatekin, Ö.; McMahon, J.; Agrusa, H. F.; Nakano, R.; et al. (March 2023).Tidal Dissipation in Didymos Following the DART Impact(PDF).54th Lunar and Planetary Science Conference 2023. Lunar and Planetary Institute.Retrieved4 February2023.
  29. ^Main-Belt Comets May Have Been Source Of Earths Water,Space Daily, Mar 23, (2006).
  30. ^abJewitt, David; Hsieh, Henry (2022). "The Asteroid-Comet Continuum". In Meech, K.; Combi, M. (eds.).Comets III.University of Arizona Press. p. 34.arXiv:2203.01397.Bibcode:2022arXiv220301397J.
  31. ^Tholen, David J.; Sheppard, Scott S.; Trujillo, Chad A. (November 2015). "Evidence for an Impact Event on (493) Griseldis".DPS.47:414.03.Bibcode:2015DPS....4741403T.
  32. ^Bodewits, D.; Kelley, M. S.; Li, J.-Y.; Landsman, W. B.; Besse, S.; A’Hearn, M. F. (2011-05-20). "Collisional Excavation of Asteroid (596) Scheila".The Astrophysical Journal.733(1): L3.arXiv:1104.5227.Bibcode:2011ApJ...733L...3B.doi:10.1088/2041-8205/733/1/L3.ISSN2041-8205.S2CID54187826.
  33. ^Yang, Bin; Hsieh, Henry (2011-08-20)."Near-Infrared Observations of Comet-Like Asteroid (596) Scheila".The Astrophysical Journal.737(2): L39.arXiv:1107.3845.Bibcode:2011ApJ...737L..39Y.doi:10.1088/2041-8205/737/2/L39.ISSN2041-8205.
  34. ^Hsieh, Henry H.; Yang, Bin; Haghighipour, Nader (2012-01-01). "Optical and Dynamical Characterization of Comet-Like Main-Belt Asteroid (596) Scheila".The Astrophysical Journal.744(1): 9.arXiv:1109.3477.Bibcode:2012ApJ...744....9H.doi:10.1088/0004-637X/744/1/9.ISSN0004-637X.S2CID15039916.
  35. ^Russell, C. T.; Aroian, R.; Arghavani, M.; Nock, K. (1984-10-05). "Interplanetary Magnetic Field Enhancements and Their Association with the Asteroid 2201 Oljato".Science.226(4670): 43–45.Bibcode:1984Sci...226...43R.doi:10.1126/science.226.4670.43.ISSN0036-8075.PMID17815417.S2CID10618035.
  36. ^Jewitt, David; Li, Jing; Agarwal, Jessica (17 June 2013). "The Dust Tail of Asteroid (3200) Phaethon".The Astrophysical Journal.771(2): L36.arXiv:1306.3741.Bibcode:2013ApJ...771L..36J.doi:10.1088/2041-8205/771/2/L36.S2CID37387069.
  37. ^Kleyna, Jan T.; Hainaut, Olivier R.; Meech, Karen J.; Hsieh, Henry H.; Fitzsimmons, Alan; Micheli, Marco; Keane, Jacqueline V.; Denneau, Larry; Tonry, John; Heinze, Aren; Bhatt, Bhuwan C. (2019-04-01)."The Sporadic Activity of (6478) Gault: A YORP-driven Event?"(PDF).The Astrophysical Journal.874(2): L20.arXiv:1903.12142.Bibcode:2019ApJ...874L..20K.doi:10.3847/2041-8213/ab0f40.ISSN2041-8213.S2CID85544222.
  38. ^Sanchez, Juan A.; Reddy, Vishnu; Thirouin, Audrey; Wright, Edward L.; Linder, Tyler R.; Kareta, Theodore; Sharkey, Benjamin (2019-08-05)."Physical Characterization of Active Asteroid (6478) Gault".The Astrophysical Journal.881(1): L6.arXiv:1907.06643.Bibcode:2019ApJ...881L...6S.doi:10.3847/2041-8213/ab31ac.hdl:10150/634151.ISSN2041-8213.S2CID196831757.
  39. ^Chandler, Colin Orion; Kueny, Jay; Gustafsson, Annika; Trujillo, Chadwick A.; Robinson, Tyler D.; Trilling, David E. (2019-05-22)."Six Years of Sustained Activity in (6478) Gault".The Astrophysical Journal.877(1): L12.Bibcode:2019ApJ...877L..12C.doi:10.3847/2041-8213/ab1aaa.ISSN2041-8213.
  40. ^Sheppard, Scott S.; Trujillo, Chadwick (2015-01-08). "Discovery and Characteristics of the Rapidly Rotating Active Asteroid (62412) 2000 SY178 in the Main Belt".The Astronomical Journal.149(2): 44.arXiv:1410.1528.Bibcode:2015AJ....149...44S.doi:10.1088/0004-6256/149/2/44.ISSN1538-3881.S2CID56464879.
  41. ^Ferrín, Ignacio; Hamanowa, Hiromi; Hamanowa, Hiroko; Hernández, Jesús; Sira, Eloy; Sánchez, Albert; Zhao, Haibin; Miles, Richard (September 2012). "The 2009 Apparition of methuselah comet 107P/Wilson–Harrington: A case of comet rejuvenation?".Planetary and Space Science.70(1): 59–72.arXiv:1205.6874.doi:10.1016/j.pss.2012.05.022.S2CID118530975.
  42. ^Fernández, Yanga R.; McFadden, Lucy A.; Lisse, Carey M.; Helin, Eleanor F.; Chamberlin, Alan B. (July 1997). "Analysis of POSS Images of Comet–Asteroid Transition Object 107P/1949 W1 (Wilson–Harrington)".Icarus.128(1): 114–126.Bibcode:1997Icar..128..114F.doi:10.1006/icar.1997.5728.
  43. ^Hsieh, Henry H.; Jewitt, David C.; Fernández, Yanga R. (May 2004)."The Strange Case of 133P/Elst-Pizarro: A Comet among the Asteroids".The Astronomical Journal.127(5): 2997–3017.Bibcode:2004AJ....127.2997H.doi:10.1086/383208.ISSN0004-6256.
  44. ^Jewitt, David; Ishiguro, Masateru; Weaver, Harold; Agarwal, Jessica; Mutchler, Max; Larson, Steven (2014-04-11)."Hubble Space Telescopeinvestigation of Main-Belt Comet 133P/Elst-Pizarro".The Astronomical Journal.147(5): 117.arXiv:1402.5571.Bibcode:2014AJ....147..117J.doi:10.1088/0004-6256/147/5/117.ISSN0004-6256.
  45. ^Hsieh, Henry H.; Denneau, Larry; Fitzsimmons, Alan; Hainaut, Olivier R.; Ishiguro, Masateru; Jedicke, Robert; Kaluna, Heather M.; Keane, Jacqueline V.; Kleyna, Jan; Lacerda, Pedro; MacLennan, Eric M. (2014-03-14)."Search for the Return of Activity in Active Asteroid 176P/Linear".The Astronomical Journal.147(4): 89.arXiv:1408.4865.Bibcode:2014AJ....147...89H.doi:10.1088/0004-6256/147/4/89.ISSN0004-6256.
  46. ^Hsieh, Henry H.; Meech, Karen J.; Pittichová, Jana (2011-07-20)."Main-Belt Comet 238P/Read Revisited".The Astrophysical Journal.736(1): L18.arXiv:1106.0045.Bibcode:2011ApJ...736L..18H.doi:10.1088/2041-8205/736/1/L18.ISSN2041-8205.
  47. ^Jewitt, David; Yang, Bin; Haghighipour, Nader (2009-05-01)."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.ISSN0004-6256.
  48. ^Agarwal, Jessica; Jewitt, David; Mutchler, Max; Weaver, Harold; Larson, Stephen (September 2017). "A binary main-belt comet".Nature.549(7672): 357–359.arXiv:1710.03454.Bibcode:2017Natur.549..357A.doi:10.1038/nature23892.ISSN0028-0836.PMID28933430.S2CID4469577.
  49. ^Jewitt, David; Agarwal, Jessica; Weaver, Harold; Mutchler, Max; Larson, Stephen (2013-11-07)."The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5".The Astrophysical Journal.778(1): L21.arXiv:1311.1483.Bibcode:2013ApJ...778L..21J.doi:10.1088/2041-8205/778/1/L21.ISSN2041-8205.
  50. ^Moreno, F.; Licandro, J.; Álvarez-Iglesias, C.; Cabrera-Lavers, A.; Pozuelos, F. (2014-01-16). "Intermittent Dust Mass Loss from Activated Asteroid P/2013 P5 (Panstarrs)".The Astrophysical Journal.781(2): 118.arXiv:1312.5895.Bibcode:2014ApJ...781..118M.doi:10.1088/0004-637X/781/2/118.ISSN0004-637X.S2CID119298012.
  51. ^Hainaut, O. R.; Boehnhardt, H.; Snodgrass, C.; Meech, K. J.; Deller, J.; Gillon, M.; Jehin, E.; Kuehrt, E.; Lowry, S. C.; Manfroid, J.; Micheli, M. (March 2014)."Continued activity in P/2013 P5 PANSTARRS: Unexpected comet, rotational disintegration, or rubbing binary asteroid?".Astronomy & Astrophysics.563:A75.doi:10.1051/0004-6361/201322864.ISSN0004-6361.
  52. ^Hui, Man-To; Jewitt, David (2015-03-16). "Archival Observations of Active Asteroid 313P/Gibbs".The Astronomical Journal.149(4): 134.Bibcode:2015AJ....149..134H.doi:10.1088/0004-6256/149/4/134.ISSN1538-3881.S2CID44820411.
  53. ^Jewitt, David; Agarwal, Jessica; Weaver, Harold; Mutchler, Max; Li, Jing; Larson, Stephen (2016-09-06)."HUBBLE SPACE TELESCOPE OBSERVATIONS OF ACTIVE ASTEROID 324P/La SAGRA".The Astronomical Journal.152(3): 77.arXiv:1606.08522.Bibcode:2016AJ....152...77J.doi:10.3847/0004-6256/152/3/77.hdl:10150/621499.ISSN1538-3881.S2CID119293534.
  54. ^Stevenson, R.; Kramer, E. A.; Bauer, J. M.; Masiero, J. R.; Mainzer, A. K. (2012-11-10)."Characterization of Active Main Belt Object P/2012 F5 (Gibbs): A Possible Impacted Asteroid".The Astrophysical Journal.759(2): 142.arXiv:1209.5450.Bibcode:2012ApJ...759..142S.doi:10.1088/0004-637X/759/2/142.ISSN0004-637X.
  55. ^Drahus, Michał; Waniak, Wacław; Tendulkar, Shriharsh; Agarwal, Jessica; Jewitt, David; Sheppard, Scott S. (2015-03-20)."Fast Rotation and Trailing Fragments of the Active Asteroid P/2012 F5 (Gibbs)".The Astrophysical Journal.802(1): L8.arXiv:1503.05632.Bibcode:2015ApJ...802L...8D.doi:10.1088/2041-8205/802/1/L8.ISSN2041-8213.
  56. ^Jewitt, David; Ishiguro, Masateru; Agarwal, Jessica (2013-01-24). "Large Particles in Active Asteroid P/2010 A2".The Astrophysical Journal.764(1): L5.arXiv:1301.2566.Bibcode:2013ApJ...764L...5J.doi:10.1088/2041-8205/764/1/L5.ISSN2041-8205.S2CID37325835.
  57. ^Hsieh, Henry H.; Kaluna, Heather M.; Novaković, Bojan; Yang, Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Fitzsimmons, Alan; Jedicke, Robert; Kleyna, Jan; Vereš, Peter (2013-06-11). "Main-Belt Comet P/2012 T1 (Panstarrs)".The Astrophysical Journal.771(1): L1.arXiv:1305.5558.Bibcode:2013ApJ...771L...1H.doi:10.1088/2041-8205/771/1/L1.hdl:1721.1/93906.ISSN2041-8205.S2CID166874.
  58. ^Jewitt, David; et al. (18 January 2019)."Active Asteroid P/2017 S5 (ATLAS)".The Astronomical Journal.157(2): 54.arXiv:1812.00060.Bibcode:2019AJ....157...54J.doi:10.3847/1538-3881/aaf563.S2CID119508428.
  59. ^Kim, Yoonyoung; Jewitt, David; Agarwal, Jessica; Mutchler, Max; Li, Jing; Weaver, Harold (July 2022)."Hubble Space Telescope Observations of Active Asteroid P/2020 O1 (Lemmon-PANSTARRS)".The Astrophysical Journal Letters.933(1): 10.arXiv:2206.07703.Bibcode:2022ApJ...933L..15K.doi:10.3847/2041-8213/ac78de.S2CID249674510.L15.
  60. ^Jewitt, David; Agarwal, Jessica; Li, Jing; Weaver, Harold; Mutchler, Max; Larson, Stephen (2014-03-06). "Disintegrating Asteroid P/2013 R3".The Astrophysical Journal.784(1): L8.arXiv:1403.1237.Bibcode:2014ApJ...784L...8J.doi:10.1088/2041-8205/784/1/L8.ISSN2041-8205.S2CID54680553.
  61. ^Moreno, F.; Licandro, J.; Cabrera-Lavers, A.; Pozuelos, F. J. (2016-07-27)."Dust Loss from Activated Asteroid P/2015 X6".The Astrophysical Journal.826(2): 137.arXiv:1605.04802.Bibcode:2016ApJ...826..137M.doi:10.3847/0004-637X/826/2/137.ISSN1538-4357.S2CID118558049.
  62. ^Moreno, F.; Licandro, J.; Cabrera-Lavers, A.; Pozuelos, F. J. (2016-07-26)."Early Evolution of Disrupted Asteroid P/2016 G1 (PANSTARRS)".The Astrophysical Journal.826(2): L22.arXiv:1607.03375.Bibcode:2016ApJ...826L..22M.doi:10.3847/2041-8205/826/2/L22.ISSN2041-8213.
  63. ^Hui ( hứa văn thao ), Man-To; Jewitt, David; Du ( đỗ tân nam ), Xinnan (2017-03-07)."Split Active Asteroid P/2016 J1 (PANSTARRS)".The Astronomical Journal.153(4): 141.arXiv:1702.02766.Bibcode:2017AJ....153..141H.doi:10.3847/1538-3881/aa6039.ISSN1538-3881.S2CID118824144.
  64. ^abcSnodgrass, C.; Jones, G.H.; Boehnhardt, H.; Gibbings, A.; Homeister, M.; Andre, N.; Beck, P.; Bentley, M.S.; Bertini, I.; Bowles, N.; Capria, M.T.; Carr, C.; Ceriotti, M.; Coates, A.J.; Della Corte, V.; Donaldson Hanna, K.L.; Fitzsimmons, A.; Gutiérrez, P.J.; Hainaut, O.R.; Herique, A.; Hilchenbach, M.; Hsieh, H.H.; Jehin, E.; Karatekin, O.; Kofman, W.; Lara, L.M.; Laudan, K.; Licandro, J.; Lowry, S.C.; et al. (2018). "The Castalia mission to Main Belt Comet 133P/Elst-Pizarro".Advances in Space Research.62(8): 1947–1976.arXiv:1709.03405.Bibcode:2018AdSpR..62.1947S.doi:10.1016/j.asr.2017.09.011.S2CID55821241.
  65. ^Lauretta, D. S.; Hergenrother, C. W.; Chesley, S. R.; Leonard, J. M.; Pelgrift, J. Y.; et al. (6 Dec 2019)."Episodes of particle ejection from the surface of the active asteroid (101955) Bennu"(PDF).Science.366(6470): eaay3544.Bibcode:2019Sci...366.3544L.doi:10.1126/science.aay3544.PMID31806784.S2CID208764910.
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