Active asteroid

Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics.[1] That is, they show comae, tails, or other visual evidence of mass-loss (like a comet), but their orbit remains within Jupiter's orbit (like an asteroid).[2][3] These bodies were originally designated main-belt comets (MBCs) in 2006 by astronomers David Jewitt and Henry Hsieh, but this name implies they are necessarily icy in composition like a comet and that they only exist within the main-belt, whereas the growing population of active asteroids shows that this is not always the case.[2][4][5]

Asteroid (596) Scheila displaying a comet-like appearance on December 12, 2010.

The first active asteroid discovered is 7968 Elst–Pizarro. It was discovered (as an asteroid) in 1979 but then was found to have a tail by Eric Elst and Guido Pizarro in 1996 and given the cometary designation 133P/Elst-Pizarro.[2][6]


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

  1. semi-major axis a < aJupiter (5.20 AU)
  2. Tisserand parameter with respect to Jupiter TJ > 3.08

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 real Solar System deviating from an idealized restricted three-body problem.[3]

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


Disintegration of asteroid P/2013 R3 observed by the Hubble Space Telescope (6 March 2014).[8][9]

Some active asteroids display a cometary dust tail only for a part of their orbit near perihelion. This strongly suggests that volatiles at their surfaces are sublimating, driving off the dust.[10] Activity in 133P/Elst–Pizarro is 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 of volatile material helping to expose them to solar 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 of 596 Scheila indicated that large amounts of dust were kicked up by the impact of another asteroid of approximately 35 meters in diameter.

P/2013 R3Edit

P/2013 R3 (CATALINA-PANSTARRS) was discovered independently by two observers by Richard E. Hill using the Catalina Sky Survey's 0.68-m Schmidt telescope and by Bryce T. Bolin using the 1.8-m Pan-STARRS1 telescope on Haleakala.[14] The discovery images taken by Pan-STARRS1 showed 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 m Gran Telescopio Canarias on the island of La 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 the Sierra Nevada Observatory in Granada on October 12.[15]

NASA reported on a series of images taken by the Hubble Space Telescope between October 29, 2013, and January 14, 2014, that show the increasing separation of the four main bodies.[16] The Yarkovsky–O'Keefe–Radzievskii–Paddack effect, caused by sunlight, increased the spin rate until the centrifugal force caused the rubble pile to separate.[16]


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.[17] European scientists have proposed a sample-return mission from a MBC called Caroline to analyse the content of volatiles and collect dust samples.[10]


Identified members of this morphology class include:

Name Semi-major axis
TJup Diameter
1 Ceres 2.77 2.56 3.309 939 Water sublimation[3]
493 Griseldis 3.12 2.57 3.140 46 Impact[18]
596 Scheila 2.92 2.44 3.209 113 Impact[19][20][21]
2201 Oljato 2.18 0.62 3.299 1.8 Outgassing[22]
3200 Phaethon 1.27 0.14 4.510 5.8 Thermal fracturing and/or desiccation cracking[23]
4015 Wilson–Harrington 2.64 0.98 3.082 4 Sublimation[24][25]
6478 Gault 2.31 1.86 3.461 3.7 Rotational spin-up[26][27][28]
7968 Elst–Pizarro (133P/Elst–Pizarro, P/1996 N2) 3.15 2.64 3.184 3.9 Impact/ice sublimation[29][30]
(62412) 2000 SY178 3.15 2.90 3.197 5 Rubble pile disintegration[31]
101955 Bennu 1.13 0.90 5.525 0.49 Thermal fracturing, volatile release, and/or impacts[32]
118401 LINEAR (176P/LINEAR) 3.19 2.57 3.167 4 Impact/ice sublimation[33]
(248370) 2005 QN173 3.07 2.37 3.192 3.6 Impact?
(300163) 2006 VW139 (288P) 3.05 2.44 3.204 1.8 Ice sublimation[34]
233P/La Sagra (P/2005 JR71) 3.04 1.79 3.081 Impact/ice sublimation
238P/Read (P/2005 U1) 3.16 2.36 3.154 0.6 Impact/ice sublimation[35]
259P/Garradd (P/2008 R1) 2.72 1.79 3.217 0.6 Sublimation/orbit change[36]
311P/PANSTARRS (P/2013 P5) 2.19 1.95 3.661 0.5 Rubble pile disintegration[37][38][39]
313P/Gibbs (P/2003 S10) 3.16 2.39 3.133 1.0 Ice sublimation[40]
324P/La Sagra (P/2010 R2) 3.10 2.62 3.100 Impact/ice sublimation[41]
331P/Gibbs (P/2012 F5) 3.00 2.88 3.228 Rubble pile disintegration[42][43]
348P/PANSTARRS (P/2011 A5) 3.17 2.21 3.062
354P/LINEAR (P/2010 A2) 2.29 2.00 3.583 0.22 Impact[44]
358P/PANSTARRS (P/2012 T1) 3.15 2.41 3.134 0.32 Impact/ice sublimation[45]
367P/Catalina (P/2011 CR42) 3.51 2.53 3.042
P/2013 R3-A (Catalina-PANSTARRS) 3.03 2.20 3.184 0.2 Rubble pile disintegration[46]
P/2013 R3-B (Catalina-PANSTARRS) 3.03 2.20 3.184 0.2 Rubble pile disintegration[46]
P/2014 C1 (TOTAS) 3.04 1.69 3.077
P/2015 X6 (PANSTARRS) 2.75 2.29 3.319 Rubble pile disintegration or ice sublimation[47]
P/2016 G1 (PANSTARRS) 2.58 2.04 3.367 0.2 Impact[48]
P/2016 J1-A (PANSTARRS) 3.17 2.45 3.113 0.5 Impact/ice sublimation/rubble pile disintegration[49]
P/2016 J1-B (PANSTARRS) 3.17 2.45 3.113 0.2 Impact/ice sublimation/rubble pile disintegration[49]
P/2016 P1 (PANSTARRS) 3.23 2.28 2.967
P/2017 S5 (ATLAS) 3.17 2.18 3.092 0.5 Ice sublimation[50]
P/2017 S8 (PANSTARRS) 2.78 1.68 3.040
P/2017 S9 (PANSTARRS) 3.16 2.20 3.087
P/2018 P3 (PANSTARRS) 3.01 1.76 3.096
P/2019 A3 (PANSTARRS) 3.15 2.31 3.100
P/2019 A4 (PANSTARRS) 2.61 2.36 3.365
P/2019 A7 (PANSTARRS) 3.19 2.68 3.103
P/2020 O1 (Lemmon-PANSTARRS) 2.65 2.33 3.376
P/2021 A5 (PANSTARRS) 3.05 2.62 3.147
P/2021 T3 (PANSTARRS) 3.02 2.06 3.090


Asteroid (101955) Bennu seen ejecting particles on January 6, 2019, in images taken by the OSIRIS-REx spacecraft

Castalia is a proposed mission concept for a robotic spacecraft to explore 133P/Elst–Pizarro and make the first in situ measurements of water in the asteroid belt, and thus, help solve the mystery of the origin of Earth's water.[51] The lead is Colin Snodgrass, from The Open University in the UK. Castalia was proposed in 2015 and 2016 to the European Space Agency within the Cosmic Vision programme missions M4 and M5, but it was not selected. The team continues to mature the mission concept and science objectives.[51] Because of the construction time required and orbital dynamics, a launch date of October 2028 was proposed.[51]

On January 6, 2019, the OSIRIS-REx mission first observed episodes of particle ejection from 101955 Bennu shortly after entering orbit around the near-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.[32]

See alsoEdit


  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. Retrieved 18 November 2022.
  2. ^ a b c d David Jewitt. "The Active Asteroids". UCLA, Department of Earth and Space Sciences. Retrieved 2020-01-26.
  3. ^ a b c d Jewitt, David; Hsieh, Henry; Agarwal, Jessica (2015). Michel, P.; et al. (eds.). The Active Asteroids (PDF). Asteroids IV. University of Arizona. pp. 221–241. arXiv:1502.02361. doi:10.2458/azu_uapress_9780816532131-ch012. ISBN 9780816532131. S2CID 119209764. Retrieved 2020-01-30.
  4. ^ a b Chang, 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. Retrieved 21 March 2019.
  5. ^ "Hubble Observes Six Tails from an Unusual Asteroid". Space Telescope Science Institute (STScI), official YouTube channel for the Hubble Space Telescope. Archived from the original on 2021-12-22. Retrieved 2014-11-15.
  6. ^ Hsieh, Henry (January 20, 2004). "133P/Elst-Pizarro". UH Institute for Astronomy. Archived from the original on 26 October 2011. Retrieved 22 June 2012.
  7. ^ a b c d Henry H. Hsieh (May 2010). "Main Belt Comets". Hawaii. Archived from the original on 2011-08-06. Retrieved 2010-12-15. (older 2010 site) Archived 2009-08-10 at the Wayback Machine
  8. ^ Harrington, J.D.; Villard, Ray (6 March 2014). "RELEASE 14-060 NASA's Hubble Telescope Witnesses Asteroid's Mysterious Disintegration". NASA. Retrieved 6 March 2014.
  9. ^ "Hubble witnesses an asteroid mysteriously disintegrating". ESA / HUBBLE. Retrieved 12 March 2014.
  10. ^ a b The 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. PMID 20944743. S2CID 205222567.
  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. PMID 20944742. S2CID 4330570.
  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. Central Bureau for Astronomical Telegrams. 3658: 1. Bibcode:2013CBET.3658....1H. Retrieved 27 September 2013.
  15. ^ a b Licandro, Javier. "Main Belt Comet P/2013 R3 is breaking apart". IAC Press Release. Retrieved 17 October 2013.
  16. ^ a b "Hubble Witnesses Asteroid's Mysterious Disintegration | Science Mission Directorate".
  17. ^ Main-Belt Comets May Have Been Source Of Earths Water, Space Daily, Mar 23, (2006).
  18. ^ 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.
  19. ^ 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. doi:10.1088/2041-8205/733/1/L3. ISSN 2041-8205. S2CID 54187826.
  20. ^ Yang, Bin; Hsieh, Henry (2011-08-20). "Near-Infrared Observations of Comet-Like Asteroid (596) Scheila". The Astrophysical Journal. 737 (2): L39. doi:10.1088/2041-8205/737/2/L39. ISSN 2041-8205.
  21. ^ 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. doi:10.1088/0004-637X/744/1/9. ISSN 0004-637X. S2CID 15039916.
  22. ^ 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. doi:10.1126/science.226.4670.43. ISSN 0036-8075. PMID 17815417. S2CID 10618035.
  23. ^ 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. S2CID 37387069.
  24. ^ 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. S2CID 118530975.
  25. ^ 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. doi:10.1006/icar.1997.5728.
  26. ^ 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. doi:10.3847/2041-8213/ab0f40. ISSN 2041-8213. S2CID 85544222.
  27. ^ 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. doi:10.3847/2041-8213/ab31ac. hdl:10150/634151. ISSN 2041-8213. S2CID 196831757.
  28. ^ 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. doi:10.3847/2041-8213/ab1aaa. ISSN 2041-8213.
  29. ^ 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. doi:10.1086/383208. ISSN 0004-6256.
  30. ^ 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. doi:10.1088/0004-6256/147/5/117. ISSN 0004-6256.
  31. ^ 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. doi:10.1088/0004-6256/149/2/44. ISSN 1538-3881. S2CID 56464879.
  32. ^ a b 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. PMID 31806784. S2CID 208764910.
  33. ^ 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. doi:10.1088/0004-6256/147/4/89. ISSN 0004-6256.
  34. ^ 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. doi:10.1038/nature23892. ISSN 0028-0836. PMID 28933430. S2CID 4469577.
  35. ^ Hsieh, Henry H.; Meech, Karen J.; Pittichová, Jana (2011-07-20). "Main-Belt Comet 238P/Read Revisited". The Astrophysical Journal. 736 (1): L18. doi:10.1088/2041-8205/736/1/L18. ISSN 2041-8205.
  36. ^ Jewitt, David; Yang, Bin; Haghighipour, Nader (2009-05-01). "Main-Belt Comet P/2008 R1 (Garradd)". The Astronomical Journal. 137 (5): 4313–4321. doi:10.1088/0004-6256/137/5/4313. ISSN 0004-6256.
  37. ^ 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. doi:10.1088/2041-8205/778/1/L21. ISSN 2041-8205.
  38. ^ 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. doi:10.1088/0004-637X/781/2/118. ISSN 0004-637X. S2CID 119298012.
  39. ^ 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 break-up, or rubbing binary asteroid?". Astronomy & Astrophysics. 563: A75. doi:10.1051/0004-6361/201322864. ISSN 0004-6361.
  40. ^ Hui, Man-To; Jewitt, David (2015-03-16). "Archival Observations of Active Asteroid 313P/Gibbs". The Astronomical Journal. 149 (4): 134. doi:10.1088/0004-6256/149/4/134. ISSN 1538-3881.
  41. ^ 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. doi:10.3847/0004-6256/152/3/77. hdl:10150/621499. ISSN 1538-3881. S2CID 119293534.
  42. ^ 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. doi:10.1088/0004-637X/759/2/142. ISSN 0004-637X.
  43. ^ 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. doi:10.1088/2041-8205/802/1/L8. ISSN 2041-8213.
  44. ^ 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. doi:10.1088/2041-8205/764/1/L5. ISSN 2041-8205. S2CID 37325835.
  45. ^ 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. doi:10.1088/2041-8205/771/1/L1. hdl:1721.1/93906. ISSN 2041-8205. S2CID 166874.
  46. ^ a b 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. doi:10.1088/2041-8205/784/1/L8. ISSN 2041-8205. S2CID 54680553.
  47. ^ 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. doi:10.3847/0004-637X/826/2/137. ISSN 1538-4357. S2CID 118558049.
  48. ^ 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. doi:10.3847/2041-8205/826/2/L22. ISSN 2041-8213.
  49. ^ a b Hui (許文韜), Man-To; Jewitt, David; Du (杜辛楠), Xinnan (2017-03-07). "Split Active Asteroid P/2016 J1 (PANSTARRS)". The Astronomical Journal. 153 (4): 141. arXiv:1702.02766. doi:10.3847/1538-3881/aa6039. ISSN 1538-3881. S2CID 118824144.
  50. ^ 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. S2CID 119508428.
  51. ^ a b c Snodgrass, 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. S2CID 55821241.

External linksEdit