View source for Dimorphos

{{short description|Moon of asteroid Didymos}}
{{use dmy dates|date=September 2022}}
{{Infobox planet
 | name            = Dimorphos
 | image           = Dimorphos North-Up Image Composition (final 10 full-frame images).png
 | image_scale      =
 | caption         = High-resolution view of Dimorphos, created by combining the final 10 full-frame images obtained by [[Double Asteroid Redirection Test|DART]]'s Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO). Dimorphos is oriented so that its north pole is toward the top of the image. Taken seconds before impact on September 26, 2022.
 | discovery_ref   = <ref name="johnston"/>
 | discoverer      = [[Petr Pravec]] et al.{{efn|
Astronomers involved in the discovery of Dimorphos include [[Petr Pravec|P. Pravec]], L.A.M. Benner, M.C. Nolan, P. Kusnirak, D. Pray, J.D. Giorgini, R.F. Jurgens, [[Steven J. Ostro|S.J. Ostro]], J.-L. Margot, C. Magri, A. Grauer, and S. Larson. The discovery used lightcurve and radar observations from the [[Jet Propulsion Laboratory]], Pasadena, [[California|CA]]; [[Arecibo Observatory|National Astronomy and Ionosphere Center / Arecibo Observatory]], Arecibo, [[Puerto Rico|PR]]; and [[Ondrejov Observatory]], Ondřejov, [[Czech Republic|CZ]]. <!-- In addition to those institutions, team members were affiliated with < ! - - ¿¿ --- [[Greene, Rhode Island|Greene, RI]]; --- ??  - - > [[University of California, Los Angeles|UCLA]], Los Angeles, CA; [[University of Maine]], Farmington, ME; [[University of Arkansas]], Little Rock, AK; and [[University of Arizona]], Tucson, AZ.--><ref name=johnston/>}}
 | discovery_site  = [[Ondřejov Observatory]]
 | discovered      = 20 November 2003
 | mpc_name        = Didymos I
 | alt_names       = S/2003 (65803) 1<br/>Didymos B<br/>"Didymoon"
 | pronounced      = {{IPAc-en|d|aɪ|'|m|ɔːr|f|ə|s}} {{respell|dy|MOR|fəs}}
 | named_after     = Greek word for "having two forms"<ref name=IAU-2020-06-23/>
 | satellite_of    = [[65803 Didymos]]
 | orbit_ref       = <ref name="Thomas2023"/>{{rp|pages=28}}<ref name="Horizons-orbitchange"/>
 | epoch           = 26 September 2022 23:14:24.183 [[UTC]]<br/>([[Julian day|JD]] {{val|2459849.4683355}}; impact time)<ref name="Daly2023"/>{{rp|pages=5}}<ref name="Thomas2023"/>{{rp|pages=28}}
 | semimajor       = {{val|1.206|0.035|u=km}} (pre-impact)<ref name="Thomas2023"/>{{rp|pages=28}}<br/>{{val|1.144|0.070|u=km}} (post-impact)<ref name="Fodde2023"/>{{rp|page=5}}
 | eccentricity    = {{val|0|p=≈}} (pre-impact)<ref name="Cheng2023"/>{{rp|page=15}}<br/>{{val|0.021|0.014}}<ref name="Scheirich2023"/> or {{val|0.0247|0.0002}}<ref name="PDC-Naidu2023"/>{{rp|page=16}} (post-impact)
 | period          = {{val|11.921473|0.000044|u=hr}}<br/>{{nowrap|''(11h 55m 17.3s ± 0.2s; pre-impact)''}}<ref name="Thomas2023"/>{{rp|pages=28}}<br/>{{val|11.3676|0.0014|u=hr}}<br/>{{nowrap|''(11h 22m 03.4s ± 5.0s; post-impact)''}}<ref name="Scheirich2023"/>
 | avg_speed       = {{val|0.177|u=m/s}} (pre-impact){{efn|name=orbitspeed}}
 | inclination     = {{val|169.3|1.0|u=°}} with respect to [[ecliptic]]{{efn|name=pole|Thomas et al. (2023) give Dimorphos's orbit pole orientation in terms of [[ecliptic coordinates]], where  {{mvar|λ}}  is [[ecliptic longitude]] and  {{mvar|β}}  is [[ecliptic latitude]].<ref name="Thomas2023"/>{{rp|pages=28}}  {{mvar|β}}  is the angular offset from the [[ecliptic plane]], whereas [[inclination]]  {{mvar|i}}  with respect to the ecliptic is the angular offset of the [[orbital pole]] from the [[ecliptic north pole]], at {{nobr| {{mvar|β}} {{=}} +90° ;}}  {{mvar|i}}  with respect to the ecliptic would be the [[Angle#Combining angle pairs|complement]] of  {{mvar|β}}.<ref name=coordstransform/> Therefore, given {{nobr| {{mvar|β}} {{=}} –79.3° ,}}  {{nobr| {{mvar|i}} {{=}} 90° – (–79.3°) {{=}} 169.3° }} from the ecliptic.}}
 | physical_ref    = <ref name="Daly2023"/>{{rp|page=9}}
 | dimensions      = {{val|177|x|174|x|116}}&nbsp;m (± {{val|2|x|4|x|2}}&nbsp;m)
 | mean_diameter   = {{val|151|5|u=m}} (volume equivalent)
 | surface_area    = {{val|7.58|e=4|u=m2}}<ref name="WolframAlpha"/>
 | volume          = {{val|1.81|0.18|e=6|u=m3}}
 | mass            = {{val|1.33|0.30|e=9|u=kg}} (if density is {{val|0.6|-|0.7|u=g/cm3}})<ref name="Ramsley2023"/><br/>≈ {{val|4.3|e=9|u=kg}} (if same density as Didymos)<ref name="Daly2023"/>{{rp|page=9}}
 | density         = {{val|0.6|-|0.7|u=g/cm3}}<ref name="Ramsley2023"/><br/>{{val|2.4|0.9|u=g/cm3}} (if same as Didymos)<ref name="Cheng2023"/>{{rp|pages=29}}
 | rotation        = ≈ {{val|11.9|u=hr}} ([[synchronous rotation|synchronous]]; pre-impact)<ref name="Naidu2020"/><br/>[[Chaotic rotation|chaotic]] (post-impact)<ref name="Agrusa2021"/>
 | albedo          = {{val|0.15|0.02}}<ref name="Daly2023"/>{{rp|page=6}}
 | spectral_type   = [[S-type asteroid|S]]<ref name="Nakano2022"/>
 | abs_magnitude   = {{val|21.4|0.2}}<ref name="johnston"/>{{efn|name=magdiff|Absolute magnitude of Dimorphos calculated from the addition of its magnitude difference to Didymos's absolute magnitude: 18.07 + 3.29 ≈ 21.4.<ref name="johnston"/>}}
}}

'''Dimorphos''' (formal designation '''(65803) Didymos I'''; [[provisional designation]] '''S/2003 (65803) 1''') is a [[natural satellite]] or [[minor-planet moon|moon]] of the [[near-Earth object|near-Earth asteroid]] [[65803 Didymos]], with which it forms a [[Binary asteroid|binary system]]. The moon was discovered on 20 November 2003 by [[Petr Pravec]] in collaboration with other astronomers worldwide. Dimorphos has a diameter of {{convert|177|m|ft|sp=us}} across its longest extent and it was the target of the [[Double Asteroid Redirection Test]] (DART), a [[NASA]] space mission that deliberately collided a [[spacecraft]] with the moon on 26 September 2022 to alter its orbit around Didymos. Before the impact by DART, Dimorphos had a shape of an [[oblate spheroid]] with a surface covered in [[boulder]]s but virtually no [[crater]]s.<ref name="Barnouin2023"/> The moon is thought to have formed when Didymos shed its mass due to its rapid rotation, which formed an orbiting ring of debris that conglomerated into a low-density [[rubble pile]] that became Dimorphos today.<ref name="ESA-20210330"/><ref name="Zhang2021"/><ref name="Madeira2023"/>

The DART impact reduced Dimorphos's [[orbital period]] around Didymos by 33 minutes and ejected over {{convert|1|e6kg|e6lbs}} of debris into space, producing a dust plume that temporarily brightened the Didymos system and developed a {{convert|10000|km|mi|adj=on|sp=us}}-long [[comet tail|dust tail]] that persisted for several months.<ref name="NOIRLab-20221003"/><ref name="NASA-20221215"/><ref name="Li2023"/> The DART impact is predicted to have caused global resurfacing and deformation of Dimorphos's shape, leaving an [[impact crater]] several tens of meters in diameter.<ref name="Raducan2022"/><ref name="Nakano2022"/><ref name="Raducan2023"/> Post-impact observations of brightness fluctuations within the Didymos system suggest that the impact may have either significantly deformed Dimorphos into an ellipsoidal shape or may have sent it into a [[chaotic rotation|chaotically]] [[Precession|tumbling]] rotation.<ref name="Scheirich2023"/><ref name="Pravec2023"/> If Dimorphos was in a tumbling rotation state, the moon will be subjected to irregular [[tidal force]]s by Didymos before it will eventually return to a [[tidal locking|tidally locked]] state within several decades.<ref name="Agrusa2021"/><ref name="Richardson2022"/><ref name="Meyer2023"/> The [[European Space Agency|ESA]] mission ''[[Hera (space mission)|Hera]]'' is planned to arrive at the Didymos system in 2026 to further study the effects of DART's impact on Dimorphos.

== Discovery ==
[[File:Didymos-Arecibo-radar-images.png|thumb|left|Radar images of Didymos and Dimorphos taken by the [[Arecibo Observatory]] in 2003]]
The primary asteroid Didymos was discovered in 1996 by Joe Montani of the [[Spacewatch Project]] at the University of Arizona.<ref name="johnston"/> The satellite Dimorphos was discovered on 20 November 2003, in [[photometry (astronomy)|photometric]] observations by [[Petr Pravec]] and colleagues at the [[Ondřejov Observatory]] in the Czech Republic. Dimorphos was detected through periodic dips in Didymos's brightness due to mutual [[eclipse]]s and [[occultation (astronomy)|occultations]]. With his collaborators, he confirmed from the [[Arecibo Observatory|Arecibo radar delay-Doppler]] images that Didymos is a binary system.<ref>{{cite report |last1=Pravec |first1=P. |last2=Benner |first2=L.A.M. |last3=Nolan|first3=M.C. |last4=Kusnirak |first4=P. |last5=Pray |first5=D. |last6=Giorgini |first6=J. D.|last7=Jurgens |first7=R.F. |last8=Ostro |first8=S.J. |last9=Margot |first9=J.-L. |last10=Magri |first10=C. |last11=Grauer |first11=A. |year=2003 |title={{nobr|(65803) 1996 GT}} |lang=en |series=[[IAU Circular]] |volume=8244 |page=2 |bibcode=2003IAUC.8244....2P |publisher=[[International Astronomical Union]] / [[Central Bureau for Astronomical Telegrams]] |place=Cambridge, MA |via=[[Harvard University|Harvard U.]] |url=https://ui.adsabs.harvard.edu/abs/2003IAUC.8244....2P/abstract}}</ref><ref name="Naidu2020"/>

== Etymology ==
The [[Working Group for Small Bodies Nomenclature]] of the [[International Astronomical Union]] (IAU) gave the satellite its official name on 23&nbsp;June 2020.<ref name=Temming-2020-06-29>{{cite news |last=Temming |first=Maria |date=29 June 2020 |title=An asteroid's moon got a name so NASA can bump it off its course |website=Science News |url=https://www.sciencenews.org/article/asteroid-moon-name-nasa-course-deflection-mission |access-date=1 July 2020}}</ref> The name ''Dimorphos'' is derived from a Greek word ({{lang|grc|Δίμορφος}}) meaning 'having two forms'.<ref>{{cite web |title=MPEC 2020-M83 |website=minorplanetcenter.net |publisher=[[Minor Planet Center]] |place=Cambridge, MA |url=https://minorplanetcenter.net/mpec/K20/K20M83.html |access-date=2020-07-01}}</ref><ref>{{LSJ|di/morfos|{{math|δίμορφος}}|ref}}</ref>{{efn|The name ''Dimorphos'' was suggested by [[planetary science|planetary scientist]] Kleomenis Tsiganis at the [[Aristotle University of Thessaloniki]]. Tsiganis explained that the name "has been chosen in anticipation of its changes: It will be known to us in two very different forms, the one seen by DART before the impact, and the other seen by ''Hera'' a few years later."<ref name=IAU-2020-06-23>{{cite press release |publisher=[[International Astronomical Union]] |date=23 June 2020 |title=IAU approves name of target of first NASA and ESA planetary defence missions |website=iau.org |url=https://www.iau.org/news/pressreleases/detail/iau2007/ |access-date=2020-07-01}}</ref>}} The justification for the new name reads: "As the target of the DART and ''Hera'' space missions, it will become the first celestial body in cosmic history whose form was substantially changed as a result of human intervention (the DART impact)".<ref name=IAU-2020-06-23/> The name was suggested by Kleomenis Tsiganis, a [[planetary science|planetary scientist]] at the [[Aristotle University of Thessaloniki]] and a member of both the [[Double Asteroid Redirection Test|DART]] and [[Hera (space mission)|Hera]] teams.<ref name=IAU-2020-06-23/> Prior to the IAU naming, the nickname ''Didymoon'' was used in official communications.<ref>{{cite web |title=Target: Didymoon |date=2015-03-31 |website=esa.int |publisher=[[European Space Agency]] |url=https://www.esa.int/ESA_Multimedia/Images/2015/03/Target_Didymoon |access-date=2021-11-24}}</ref>

== Exploration ==
On 24 November 2021, [[NASA]] and the [[Applied Physics Laboratory]] launched an impactor spacecraft towards Dimorphos as part of their [[Double Asteroid Redirection Test]] (DART).<ref name=Greshko-2021-11-23>{{cite news |last=Greshko |first=Michael |date=2021-11-23 |title=This NASA spacecraft will smash into an asteroid – to practice saving Earth |website=[[National Geographic]] |lang=en |url=https://www.nationalgeographic.com/science/article/nasas-dart-spacecraft-will-smash-into-an-asteroid-to-practice-saving-earth |url-status=dead |access-date=2021-11-25 |archive-url=https://web.archive.org/web/20211123113703/https://www.nationalgeographic.com/science/article/nasas-dart-spacecraft-will-smash-into-an-asteroid-to-practice-saving-earth |archive-date=2021-11-23 }}</ref><ref>{{cite press release |last=Potter |first=Sean |date=2021-11-23 |title=NASA, SpaceX Launch DART: First test mission to defend planet Earth |website=NASA |url=http://www.nasa.gov/press-release/nasa-spacex-launch-dart-first-test-mission-to-defend-planet-earth |access-date=2021-11-25}}</ref> DART was the first experiment conducted in space to test [[Asteroid impact avoidance|asteroid deflection]] as a method of defending Earth from [[Potentially hazardous object|potentially hazardous asteroids]].<ref name=Rincon-2021-11-24>{{cite news |last=Rincon |first=Paul |date=2021-11-24 |title=NASA DART asteroid spacecraft: Mission to smash into Dimorphos space rock launches |lang=en-GB |website=[[BBC News]] |url=https://www.bbc.com/news/science-environment-59327293|access-date=2021-11-25}}</ref> Following a ten-month journey to the Didymos system, the impactor collided with Dimorphos on 26 September 2022 at a speed of around {{Convert|15000|mph|km/h|abbr=off|order=flip|sp=us}}.<ref name=Rincon-2021-11-24/><ref>{{cite press release |last=Potter |first=Sean |date=2021-11-23 |title=NASA, SpaceX Launch DART: First test mission to defend planet Earth |website=NASA |publisher=[[National Aeronautics and Space Administration]] |url=http://www.nasa.gov/press-release/nasa-spacex-launch-dart-first-test-mission-to-defend-planet-earth |access-date=2021-11-25}}</ref> The collision successfully decreased Dimorphos's [[orbital period]] around Didymos by {{val|32|2}} minutes.<ref name="DartPressUpdateNASA">{{cite web |title=NASA Confirms DART Mission Impact Changed Asteroid's Motion in Space |url=https://www.nasa.gov/press-release/nasa-confirms-dart-mission-impact-changed-asteroid-s-motion-in-space |last=Dunbar |first=Brian |website=NASA |date=11 October 2022 |access-date=2022-10-11 |language=en}}</ref><ref name=Temming-2020-06-29/><ref name=Crane-2021-11-23>{{cite magazine |last=Crane |first=Leah |date=2021-11-23 |title=NASA's DART mission will try to deflect an asteroid by flying into it |magazine=[[New Scientist]] |lang=en-UK |url=https://www.newscientist.com/article/2298530-nasas-dart-mission-will-try-to-deflect-an-asteroid-by-flying-into-it/ |url-status=live |access-date=2021-11-25 |archive-url=https://web.archive.org/web/20211123132010/https://www.newscientist.com/article/2298530-nasas-dart-mission-will-try-to-deflect-an-asteroid-by-flying-into-it/ |archive-date=2021-11-23 }}</ref><ref name="DartUpdateNASA">{{cite web |last1=Nelson |first1=Bill |last2=Saccoccia |first2=Giorgio |title=Update on DART Mission to Asteroid Dimorphos (NASA News Conference) |url=https://www.youtube.com/watch?v=Zhzn0U2m5wQ |website=YouTube |date=11 October 2022 |access-date=2022-10-11 |language=en}}</ref> Fifteen days prior to its collision, the impactor released [[LICIACube]], an [[Italian Space Agency]] [[CubeSat]] that photographed the impact and the resulting dust plume as it performed a close flyby of the Didymos system.<ref name=Greshko-2021-11-23/><ref name="Nature27Sep2022"/><ref name="Planetary26Sep2022"/><ref>{{cite press release |title=DART's small satellite companion tests camera prior to Dimorphos impact |website=NASA.gov |publisher=[[National Aeronautics and Space Administration]] |url=https://www.nasa.gov/feature/dart-s-small-satellite-companion-tests-camera-prior-to-dimorphos-impact |access-date=25 September 2022}}</ref> Spacecraft and observatories such as [[Hubble Space Telescope|Hubble]], [[James Webb Space Telescope|James Webb]], ''[[Lucy (spacecraft)|Lucy]]'', [[SAAO]] and [[Asteroid Terrestrial-impact Last Alert System|ATLAS]] also captured the dust plume trailing the Didymos system in the days following the impact.<ref name="S&T27Sep2022"/><ref name=atlasref>{{cite news|url=https://gizmodo.com/telescopes-capture-dart-asteroid-impact-1849585394|title=Ground Telescopes Capture Jaw-Dropping Views of DART Asteroid Impact|quote=Telescopes around the world honed in on the historic collision, revealing a surprisingly large and bright impact plume.|author=George Dvorsky|date=September 27, 2022|publisher=Gizmodo}}</ref><ref>{{cite web |title=LICIACube Impact Images |url=https://www.nasa.gov/feature/first-images-from-italian-space-agency-s-liciacube-satellite |website=NASA |date=27 September 2022 |access-date=2 October 2022}}</ref><ref name="Li2023"/> As part of its [[Hera (space mission)|Hera mission]], [[European Space Agency|ESA]] launched three spacecraft to the Didymos system in 2024 to reach this asteroid system in December 2026 to further study the aftermath of the impact.<ref name=Crane-2021-11-23/><ref>{{cite journal |last=Witze |first=Alexandra |date=2021-11-19 |title=NASA spacecraft will slam into asteroid in first planetary-defence test |lang=en |journal=[[Nature (journal)|Nature]] |volume=600 |issue=7887 |doi=10.1038/d41586-021-03471-w |pages=17–18 |pmid=34799719 |bibcode=2021Natur.600...17W |s2cid=244428237 |doi-access=free }}</ref><ref>{{cite journal |last1=Michel |first1=Patrick |last2=Küppers |first2=Michael |last3=Bagatin |first3=Adriano Campo |last4=Carry |first4=Benoit |last5=Charnoz |first5=Sébastien |last6=Leon |first6=Julia de |last7=Fitzsimmons |first7=Alan |last8=Gordo |first8=Paulo |last9=Green |first9=Simon F. |last10=Hérique |first10=Alain |last11=Juzi |first11=Martin |last12=Karatekin |first12=Özgür |last13=Kohout |first13=Tomas |last14=Lazzarin |first14=Monica |last15=Murdoch |first15=Naomi |last16=Okada |first16=Tatsuaki |last17=Palomba |first17=Ernesto |last18=Pravec |first18=Petr |last19=Snodgrass |first19=Colin |last20=Tortora |first20=Paolo |last21=Tsiganis |first21=Kleomenis |last22=Ulamec |first22=Stephan |last23=Vincent |first23=Jean-Baptiste |last24=Wünnemann |first24=Kai |last25=Zhang |first25=Yun |last26=Raducan |first26=Sabina D. |last27=Dotto |first27=Elisabetta |last28=Chabot |first28=Nancy |last29=Cheng |first29=Andy F. |last30=Rivkin |first30=Andy |last31=Barnouin |first31=Olivier |last32=Ernst |first32=Carolyn |last33=Stickle |first33=Angela |last34=Richardson |first34=Derek C. |last35=Thomas |first35=Cristina |last36=Arakawa |first36=Masahiko |last37=Miyamoto |first37=Hirdy |last38=Nakamura |first38=Akiko |last39=Sugita |first39=Seiji |last40=Yoshikawa |first40=Makoto |last41=Abell |first41=Paul |last42=Asphaug |first42=Erik |last43=Ballouz |first43=Ronald-Louis |last44=Bottke |first44=William F. |last45=Lauretta |first45=Dante S. |last46=Walsh |first46=Kevin J. |last47=Martino |first47=Paolo |last48=Carnelli |first48=Ian |display-authors=1| title=The ESA Hera Mission: Detailed Characterization of the DART Impact Outcome and of the Binary Asteroid (65803) Didymos |journal=The Planetary Science Journal |date=1 July 2022 |volume=3 |issue=7 |pages=160 |doi=10.3847/psj/ac6f52 |bibcode=2022PSJ.....3..160M |s2cid=250599919 |language=en |issn=2632-3338|doi-access=free |hdl=10045/125568 |hdl-access=free }}</ref>
[[File:Hubble sees boulders escaping from asteroid Dimorphos (heic2307a).jpg|thumb|A trail of dust streams from Dimorphos in this [[Hubble Space Telescope]] photo taken about three months after the collision. The asteroid is surrounded by blue dots, which are boulders ranging from 1 to 6.7 metres across that were ejected by the impact.]]
The DART impact on the center of Dimorphos decreased the orbital period, previously 11.92 hours, by 33±1 minutes. This large change indicates the recoil from material excavated from the asteroid and ejected into space by the impact (known as ejecta) contributed significant momentum change to the asteroid, beyond that of the DART spacecraft itself. Researchers found the impact caused an instantaneous slowing in Dimorphos' speed along its orbit of about 2.7 millimeters per second — again indicating the recoil from ejecta played a major role in amplifying the momentum change directly imparted to the asteroid by the spacecraft. That momentum change was amplified by a factor of 2.2 to 4.9 (depending on the mass of Dimorphos), indicating the momentum change transferred because of ejecta production significantly exceeded the momentum change from the DART spacecraft alone.<ref name="nasa-march2023">{{cite web |last1=Furfaro |first1=Emily |title=NASA's DART Data Validates Kinetic Impact as Planetary Defense Method |url=https://www.nasa.gov/feature/nasa-s-dart-data-validates-kinetic-impact-as-planetary-defense-method |website=NASA |access-date=9 March 2023 |date=28 February 2023}} {{PD-notice}}</ref> While the orbital change was small, the change is in the velocity and over the course of years will accumulate to a large change in position.<ref>{{Cite web |title=NASA Pushes Through With Asteroid Deflection Mission That Could One Day Save Earth – Inquisitr |url=https://www.inquisitr.com/4346664/nasa-dart-asteroid-deflection-mission-save-earth-goes-into-design-phase/ |access-date=27 September 2022 |website=inquisitr.com|date=5 July 2017 }}</ref> For a hypothetical Earth-threatening body, even such a tiny change could be sufficient to mitigate or prevent an impact, if applied early enough. As the [[diameter of Earth]] is around 13,000 kilometers, a hypothetical asteroid impact could be avoided with as little of a shift as half of that (6,500 kilometers). A {{val|2|u=cm/s}} velocity change accumulates to that distance in approximately 10 years.<!-- 2*10^-5 km/s * 3600 s/h * 24h/day * 365 day/year = 630 km/year  -->
[[File:Two LICIACube LUKE images showing the ejecta morphology that were used to reduce the possible axis orientation solutions.webp|thumb|Dart Impact seen by LICIACube]]
By smashing into the asteroid DART 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.<ref name="nasa-march2023"/><ref>{{cite journal |last1=Li |first1=Jian-Yang |last2=Hirabayashi |first2=Masatoshi |last3=Farnham |first3=Tony L. |last4=Sunshine |first4=Jessica M. |last5=Knight |first5=Matthew M. |last6=Tancredi |first6=Gonzalo |last7=Moreno |first7=Fernando |last8=Murphy |first8=Brian |last9=Opitom |first9=Cyrielle |last10=Chesley |first10=Steve |last11=Scheeres |first11=Daniel J. |last12=Thomas |first12=Cristina A. |last13=Fahnestock |first13=Eugene G. |last14=Cheng |first14=Andrew F. |last15=Dressel |first15=Linda |last16=Ernst |first16=Carolyn M. |last17=Ferrari |first17=Fabio |last18=Fitzsimmons |first18=Alan |last19=Ieva |first19=Simone |last20=Ivanovski |first20=Stavro L. |last21=Kareta |first21=Teddy |last22=Kolokolova |first22=Ludmilla |last23=Lister |first23=Tim |last24=Raducan |first24=Sabina D. |last25=Rivkin |first25=Andrew S. |last26=Rossi |first26=Alessandro |last27=Soldini |first27=Stefania |last28=Stickle |first28=Angela M. |last29=Vick |first29=Alison |last30=Vincent |first30=Jean-Baptiste |last31=Weaver |first31=Harold A. |last32=Bagnulo |first32=Stefano |last33=Bannister |first33=Michele T. |last34=Cambioni |first34=Saverio |last35=Bagatin |first35=Adriano Campo |last36=Chabot |first36=Nancy L. |last37=Cremonese |first37=Gabriele |last38=Daly |first38=R. Terik |last39=Dotto |first39=Elisabetta |last40=Glenar |first40=David A. |last41=Granvik |first41=Mikael |last42=Hasselmann |first42=Pedro H. |last43=Herreros |first43=Isabel |last44=Jacobson |first44=Seth |last45=Jutzi |first45=Martin |last46=Kohout |first46=Tomas |last47=La Forgia |first47=Fiorangela |last48=Lazzarin |first48=Monica |last49=Lin |first49=Zhong-Yi |last50=Lolachi |first50=Ramin |last51=Lucchetti |first51=Alice |last52=Makadia |first52=Rahil |last53=Epifani |first53=Elena Mazzotta |last54=Michel |first54=Patrick |last55=Migliorini |first55=Alessandra |last56=Moskovitz |first56=Nicholas A. |last57=Ormö |first57=Jens |last58=Pajola |first58=Maurizio |last59=Sánchez |first59=Paul |last60=Schwartz |first60=Stephen R. |last61=Snodgrass |first61=Colin |last62=Steckloff |first62=Jordan |last63=Stubbs |first63=Timothy J. |last64=Trigo-Rodríguez |first64=Josep M. |title=Ejecta from the DART-produced active asteroid Dimorphos |journal=Nature |date=1 March 2023 |volume=616 |issue=7957 |pages=452–456 |doi=10.1038/s41586-023-05811-4 |pmid=36858074 |pmc=10115637 |arxiv=2303.01700 |bibcode=2023Natur.616..452L |language=en |issn=1476-4687 |display-authors=3}}</ref> Observations show that Dimorphos lost approximately 1 million kilograms after the collision.<ref>{{cite journal |last1=Witze |first1=Alexandra |title=Asteroid lost 1 million kilograms after collision with DART spacecraft |journal=Nature |date=1 March 2023 |volume=615 |issue=7951 |pages=195 |doi=10.1038/d41586-023-00601-4 |pmid=36859675 |bibcode=2023Natur.615..195W |s2cid=257282080 |url=https://www.nature.com/articles/d41586-023-00601-4 |access-date=9 March 2023 |language=en}}</ref> Impact produced a dust plume that temporarily brightened the Didymos system and developed a {{convert|10000|km|mi|adj=on|sp=us}}-long [[comet tail|dust tail]] that persisted for several months.<ref name="NOIRLab-20221003"/><ref name="NASA-20221215"/><ref name="Li2023"/> The DART impact is predicted to have caused global resurfacing and deformation of Dimorphos's shape, leaving an [[impact crater]] several tens of meters in diameter.<ref name="Raducan2022"/><ref name="Nakano2022"/><ref name="Raducan2023"/> The impact has likely sent Dimorphos into a [[chaotic rotation|chaotically]] [[Precession|tumbling]] rotation that will subject the moon to irregular [[tidal force]]s by Didymos before it will eventually return to a [[tidal locking|tidally locked]] state within several decades.<ref name="Agrusa2021"/><ref name="Richardson2022"/><ref name="Meyer2023"/> Additionally, the impact changed Dimorphos shape from a roughly symmetrical "oblate spheroid" to "a flat-topped oval", or "triaxial ellipsoid".<ref>{{Cite news |last=Andrews |first=Robin George |date=2024-02-26 |title=NASA's Crash Into an Asteroid May Have Altered Its Shape |url=https://www.nytimes.com/2024/02/26/science/nasa-crash-asteroid-dart-study.html |access-date=2024-02-28 |work=The New York Times |language=en-US |issn=0362-4331}}</ref><ref>{{cite web |title=NASA Study: Asteroid's Orbit, Shape Changed After DART Impact |url=https://www.jpl.nasa.gov/news/nasa-study-asteroids-orbit-shape-changed-after-dart-impact |website=NASA Jet Propulsion Laboratory (JPL) |access-date=22 May 2024}}</ref><ref>{{cite journal |last1=Naidu |first1=Shantanu P. |last2=Chesley |first2=Steven R. |last3=Moskovitz |first3=Nicholas |last4=Thomas |first4=Cristina |last5=Meyer |first5=Alex J. |last6=Pravec |first6=Petr |last7=Scheirich |first7=Peter |last8=Farnocchia |first8=Davide |last9=Scheeres |first9=Daniel J. |last10=Brozovic |first10=Marina |last11=Benner |first11=Lance A. M. |last12=Rivkin |first12=Andrew S. |last13=Chabot |first13=Nancy L. |title=Orbital and Physical Characterization of Asteroid Dimorphos Following the DART Impact |journal=The Planetary Science Journal |date=1 March 2024 |volume=5 |issue=3 |pages=74 |doi=10.3847/PSJ/ad26e7|doi-access=free |bibcode=2024PSJ.....5...74N }}</ref>

== Size and shape ==
Dimorphos is approximately {{convert|170|m|sp=us}} in diameter, compared to Didymos at {{convert|780|m|sp=us}}. Dimorphos does not have a confirmed mass, but it is estimated to be about {{val|5|e=9|u=kg}} (5.5 million tons), or about the same mass and size as the [[Great Pyramid of Giza]], when assuming a density of {{val|2.17|u=g/cm3}} similar to Didymos.<ref>{{Cite journal |last1=Nakano |first1=Ryota |last2=Hirabayashi |first2=Masatoshi |last3=Agrusa |first3=Harrison F. |last4=Ferrari |first4=Fabio |last5=Meyer |first5=Alex J. |last6=Michel |first6=Patrick |last7=Raducan |first7=Sabina D. |last8=Sánchez |first8=Paul |last9=Zhang |first9=Yun |date=2022-07-01 |title=NASA's Double Asteroid Redirection Test (DART): Mutual Orbital Period Change Due to Reshaping in the Near-Earth Binary Asteroid System (65803) Didymos |journal=The Planetary Science Journal |volume=3 |issue=7 |pages=148 |doi=10.3847/PSJ/ac7566 |bibcode=2022PSJ.....3..148N |s2cid=250327233 |issn=2632-3338|doi-access=free }}</ref> It is one of the smallest celestial objects given a formal name by the IAU, after [[367943 Duende]] and [[469219 Kamoʻoalewa]].<ref name="IAU-2020-06-23" />

The final few minutes of pictures from the DART mission revealed an egg-shaped body covered with boulders, suggesting it has a [[rubble pile]] structure.<ref>{{cite web |title=NASA crashes DART spacecraft into asteroid in world's 1st planetary defense test |author=Tariq Malik |url=https://www.space.com/nasa-dart-asteroid-impact-planetary-defense-success |work=Space.com |date=2022-09-26}}</ref><ref name="Science27Sep2022"/>

== Surface ==
Five boulders (''saxa'') and six craters have been given names of traditional drums from several cultures. They are approximately 10 meters across or smaller:<ref name=features>{{Cite web|url=https://planetarynames.wr.usgs.gov/SearchResults?Target=155_Dimorphos|title=Planetary Names|website=planetarynames.wr.usgs.gov}}</ref>

{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"
|+Named features
|-
! Name 
! Pronunciation !! Feature !! Named after !! Date approved<ref name=features/>
|-
| Atabaque Saxum 
| {{IPAc-en|UK|ˌ|ae|t|@|'|b|ae|k|i}} {{respell|AT|ə|BAK|ee}}<br>{{IPAc-en|US|ˌ|A:|t|@|'|b|A:|k|i}} {{respell|AH|tə|BAH|kee}} || boulder || [[atabaque]] (Brazil) || 25 Jan 2023
|-
| Bodhran Saxum 
| {{IPAc-en|ˈ|b|ɔ:|r|ɑ:|n}} {{respell|BOR|ahn}} || boulder || [[bodhrán]] (Ireland) || 25 Jan 2023
|-
| Caccavella Saxum 
| {{IPAc-en|ˌ|k|ae|k|@|'|v|E|l|@}} {{respell|KAK|ə|VEL|ə}} || boulder || [[caccavella]] <br>a.k.a. putipù (Italy) || 25 Jan 2023
|-
| Dhol Saxum 
| {{IPAc-en|'|d|O:|l}} {{respell|DAWL}} || boulder || [[dhol]] (India) || 25 Jan 2023
|-
| Pūniu Saxum 
| {{IPAc-en|'|p|u:|n|i|.|u:}} {{respell|POO|nee|oo}} || boulder || [[pūniu]] a.k.a. kilu (Hawaii) || 25 Jan 2023
|-
| Bala Crater 
| {{IPAc-en|'|b|ae|l|@}} {{respell|BAL|ə}} || crater || [[balafon]] (Guinea, Senegal, Mali) || 14 Nov 2023
|-
| Bongo Crater 
| {{IPAc-en|'|b|Q|N|g|ou}} {{respell|BONG|goh}} || crater || [[bongo drum|bongo]] (Cuba) || 14 Nov 2023
|-
| Marimba Crater
| {{IPAc-en|m|@|'|r|I|m|b|@}} {{respell|mə|RIM|bə}} || crater || [[marimba]] (Central America) || 14 Nov 2023
|-
| Msondo Crater
| {{IPAc-en|E|m|'|s|Q|n|d|ou}} {{respell|em|SON|doh}} || crater || [[msondo]] (Tanzania) || 14 Nov 2023
|-
| Naqqara Crater 
| {{IPAc-en|n|ae|'|k|a:r|@}} {{respell|na|KAR|ə}} || crater || [[naqqara]] (naker) (Mid East and India) || 14 Nov 2023
|-
| Tamboril Crater 
| {{IPAc-en|ˌ|t|ae|m|b|@|'|r|I|l}} {{respell|TAM|bər|IL}} || crater || [[tamboril (percussion)|tamboril]] (Uruguay, [[Candombe]]) || 14 Nov 2023
|}

{{multiple image
 | total_width = 600
 | align =center
 | image1 = Penultimate image of Dimorphos by DART.png
 | image2 = Dimorphos North-Up Image Composition with Named Features (final 10 full-frame images).png
 | footer = '''Left:''' Surface of Dimorphos, captured by DART two seconds before impact. '''Right:''' Composite map of Dimorphos with named features.
}}

== Orbit and rotation ==
[[File:Animation of DART around Didymos - Impact on Dimorphos.gif|thumb|Animation of DART around Didymos - Impact on Dimorphos<br>{{legend2|Magenta|DART}}{{·}}{{legend2|Lime|Didymos}}{{·}}{{legend2|Gold|Dimorphos}}]]
The primary body of the binary system, Didymos, orbits the Sun at a distance of 1.0 to 2.3&nbsp;[[Astronomical unit|AU]] once every 770&nbsp;days (2&nbsp;years and 1&nbsp;month). The pathway of the orbit has an [[Orbital eccentricity|eccentricity]] of 0.38 and an [[Orbital inclination|inclination]] of 3° with respect to the [[ecliptic]]. On 4&nbsp;October 2022 Didymos made an Earth approach of {{convert|10.6|e6km|e6mi|abbr=unit}}.<ref>{{cite report |title=65803&nbsp;Didymos |series=JPL Small-Body Database Browser |publisher=[[NASA]] / [[Jet Propulsion Laboratory]] |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2065803&view=OPC |access-date=2021-12-30 |via=ssd.jpl.nasa.gov}}</ref> Dimorphos moves in a nearly equatorial, nearly circular orbit around Didymos, with an [[orbital period]] of 11.9&nbsp;hours. Its orbit period is synchronous with its rotation, so that the same side of Dimorphos always faces Didymos. Dimorphos's orbit is [[retrograde orbit|retrograde]] relative to the [[ecliptic]] plane, in conformity with Didymos's retrograde rotation.<ref>{{cite journal |last1=Scheirich |first1=P. |last2=Pravec |first2=P. |last3=Jacobson |first3=S.A. |last4=Ďurech |first4=J. |last5=Kušnirák |first5=P. |last6=Hornoch |first6=K.|last7=Mottola |first7=S. |last8=Mommert |first8=M. |last9=Hellmich |first9=S. |last10=Pray |first10=D. |last11=Polishook |first11=D. |first12=Yu.N. |last12=Krugly |last13=Inasaridze |first13=R.Ya. |last14=Kvaratskhelia |first14=O.I. |last15=Ayvazian |first15=V. |last16=Slyusarev |first16=I. |last17=Pittichová |first17=J. |last18=Jehin |first18=E. |last19=Manfroid |first19=J. |last20=Gillon |first20=M. |last21=Galád |first21=A. |last22=Pollock |first22=J. |last23=Licandro |first23=J. |last24=Alí-Lagoa |first24=V. |last25=Brinsfield |first25=J. |last26=Molotov |first26=I.E. |display-authors=6 |year=2015 |title=The binary near-Earth asteroid {{nobr|(175706) 1996 FG3}} – an observational constraint on its orbital evolution |journal=[[Icarus (journal)|Icarus]] |volume=245 |pages=56–63 |arxiv=1406.4677 |bibcode=2015Icar..245...56S |doi=10.1016/j.icarus.2014.09.023 |s2cid=119248574}}</ref> 

Dimorphos's rotation is being slowed down by the [[YORP effect]], with an estimated rotation period [[doubling time]] of 86,000 years. However, because it is in orbit around Didymos, [[tidal force]]s keep the moon locked in [[synchronous rotation]].<ref name="Kanamaru2023"/>

== See also ==
* [[354P/LINEAR]] – a main-belt asteroid that was naturally impacted by another asteroid sometime before 2010
* [[P/2016 G1 (PanSTARRS)]] – another main-belt asteroid that was impacted by an asteroid in 2016

== Footnotes ==
{{notelist|notes=

{{efn|name=orbitspeed|For a [[circular orbit]] with negligible eccentricity, as in the case of Dimorphos, the mean [[orbital speed]] can be approximated by the time {{mvar|T}} it takes to complete one revolution around its orbital [[circumference]], with the radius being its [[semi-major axis]] {{mvar|a}}: &nbsp;<math>v = {2 \pi a \over T}</math>.}}

}}

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  |url = https://www.hou.usra.edu/meetings/lpsc2023/pdf/2605.pdf
  |conference = 54th Lunar and Planetary Science Conference 2023
  |publisher = Lunar and Planetary Institute
  |date = March 2023 <!-- posted in Feb 2023 before scheduled presentation in Mar 2023 -->
  |issue = 2605
  |accessdate = 4 February 2023}}</ref>

<ref name="Raducan2023">{{cite conference
  |display-authors = etal
  |first1 = S. D. |last1 = Raducan
  |first2 = M. |last2 = Jutzi
  |first3 = Y. |last3 = Zhang
  |first4 = A. F. |last4 = Cheng
  |first5 = G. S. |last5 = Collins
  |first6 = T. M. |last6 = Davison
  |title =Low Strength of Asteroid Dimorphos As Demonstrated by the Dart Impact
  |url = https://www.hou.usra.edu/meetings/lpsc2023/pdf/2033.pdf
  |conference = 54th Lunar and Planetary Science Conference 2023
  |publisher = Lunar and Planetary Institute
  |date = March 2023 <!-- posted in Feb 2023 before scheduled presentation in Mar 2023 -->
  |issue = 2033
  |accessdate = 4 February 2023}}</ref>

<ref name="Meyer2023">{{cite conference
  |display-authors = etal
  |first1 = A. J. |last1 = Meyer
  |first2 = G. |last2 = Noiset
  |first3 = Ö. |last3 = Karatekin
  |first4 = J. |last4 = McMahon
  |first5 = H. F. |last5 = Agrusa
  |first6 = R. |last6 = Nakano
  |title = Tidal Dissipation in Didymos Following the DART Impact
  |url = https://www.hou.usra.edu/meetings/lpsc2023/pdf/2105.pdf
  |conference = 54th Lunar and Planetary Science Conference 2023
  |publisher = Lunar and Planetary Institute
  |date = March 2023 <!-- posted in Feb 2023 before scheduled presentation in Mar 2023 -->
  |issue = 2105
  |accessdate = 4 February 2023}}</ref>

<ref name="Ramsley2023">{{cite conference
  |first1 = K. R. |last1 = Ramsley
  |first2 = J. W. |last2 = Head
  |title = DART Impact: Setting Constraints Using the Tsiolkovsky Rocket Equation
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  |conference = 54th Lunar and Planetary Science Conference 2023
  |publisher = Lunar and Planetary Institute
  |date = March 2023 <!-- posted in Feb 2023 before scheduled presentation in Mar 2023 -->
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  |accessdate = 4 February 2023}}</ref>

<ref name="Kanamaru2023">{{cite conference
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  |first1 = M. |last1 = Kanamaru
  |first2 = G. |last2 = Tommei
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  |first4 = N. |last4 = Sakatani
  |first5 = Y. |last5 = Shimaki
  |first6 = S. |last6 = Tanaka
  |title = Thermophysical Model Development To Simulate Non-Gravitational Acceleration on Binary Asteroid
  |url = https://www.hou.usra.edu/meetings/lpsc2023/pdf/2949.pdf
  |conference = 54th Lunar and Planetary Science Conference 2023
  |publisher = Lunar and Planetary Institute
  |date = March 2023 <!-- posted in Feb 2023 before scheduled presentation in Mar 2023 -->
  |issue = 2949
  |accessdate = 4 February 2023}}</ref>

<ref name="Madeira2023">{{cite journal
  |first1 = Gustavo |last1 = Madeira
  |first2 = Sébastien |last2 = Charnoz
  |first3 = Ryuki |last3 = Hyodo
  |title = Dynamical origin of Dimorphos from fast spinning Didymos
  |journal = Icarus
  |date = April 2023
  |volume = 394
  |id = 115428
  |pages = 16
  |doi = 10.1016/j.icarus.2023.115428
  |arxiv = 2301.02121
  |bibcode = 2023Icar..39415428M
  |s2cid = 255440287}}</ref>

<ref name="Cheng2023">{{cite journal
  |display-authors = etal
  |first1 = Andrew |last1 = Cheng
  |first2 = Harrison |last2 = Agrusa
  |first3 = Brent |last3 = Barbee
  |first4 = Alex |last4 = Meyer
  |first5 = Tony |last5 = Farnham
  |first6 = Sabina |last6 = Raducan
  |title = Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos
  |url = https://assets.researchsquare.com/files/rs-2339073/v1_covered.pdf?c=1670565284
  |journal = Nature
  |date = March 2023
  |volume = 616 |issue = 7957 |pages = 457–460 |doi = 10.1038/s41586-023-05878-z
  |pmid = 36858075 |pmc = 10115652 |arxiv = 2303.03464
  |bibcode = 2023Natur.616..457C}}</ref>

<ref name="Daly2023">{{cite journal
  |display-authors = etal
  |first1 = R. Terik |last1 = Daly
  |first2 = Carolyn M. |last2 = Ernst
  |first3 = Olivier S. |last3 = Barnouin
  |first4 = Nancy L. |last4 = Chabot
  |first5 = Andrew S. |last5 = Rivkin
  |first6 = Andrew F. |last6 = Cheng
  |title = Successful Kinetic Impact into an Asteroid for Planetary Defense
  |url = https://www.nature.com/articles/s41586-023-05810-5.epdf?sharing_token=jXTdHVlr11N2aOxA24DQBNRgN0jAjWel9jnR3ZoTv0NHE9hcFPwYuoQWDVTaVa0x4GyKs5Owh-6-nPe432v_6KQRKJOCfnGVhme0HLffSgL3Y4QVPuAFf4BXuGPBDV2W114tRBHiXdraz_ZBBmDUEs5-_v7OYz5yMWrK_qElp2xf3UQmYtOkfuB_QsbDFbFt21kVRwCvLCx1MO4n1oK7N2OYDHsJVEQ6POGiA3FiMrD_eHe0KqNxxFwwogC3MnDqAQ66V9YB8R-v2iunQ9cd9Q%3D%3D&tracking_referrer=www.space.com
  |journal = Nature
  |date = March 2023
  |volume = 616 |issue = 7957 |pages = 443–447 |doi = 10.1038/s41586-023-05810-5
  |pmid = 36858073 |pmc = 10115643 |arxiv = 2303.02248
  |bibcode = 2023Natur.616..443D }}</ref>

<!-- unused
<ref name="Graykowski2023">{{cite journal
  |display-authors = etal
  |first1 = Ariel |last1 = Graykowski
  |first2 = Ryan A. |last2 = Lambert
  |first3 = Franck |last3 = Marchis
  |first4 = Dorian |last4 = Cazeneuve
  |first5 = Paul A. |last5 = Dalba
  |first6 = Thomas M. |last6 = Esposito
  |title = Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact
  |journal = Nature
  |date = March 2023
  |volume = 616 |issue = 7957 |pages = 461–464 |doi = 10.1038/s41586-023-05852-9
  |pmid = 36858076 |pmc = 10115630 |arxiv = 2303.05548
  |bibcode = 2023arXiv230305548G}}</ref>
-->

<ref name="Li2023">{{cite journal
  |display-authors = etal
  |first1 = Jian-Yang
  |last1 = Li
  |first2 = Masatoshi
  |last2 = Hirabayashi
  |first3 = Tony
  |last3 = Farnham
  |first4 = Matthew
  |last4 = Knight
  |first5 = Gonzalo
  |last5 = Tancredi
  |first6 = Fernando
  |last6 = Moreno
  |title = Ejecta from the DART-produced active asteroid Dimorphos
  |url = https://assets.researchsquare.com/files/rs-2292349/v1/34562254-db7b-4289-a7ff-238159687528.pdf?c=1669139626
  |journal = Nature
  |date = March 2023
  |volume = 616
  |issue = 7957
  |pages = 452–456
  |doi = 10.1038/s41586-023-05811-4
  |pmid = 36858074
  |pmc = 10115637
  |arxiv = 2303.01700
  |bibcode = 2023Natur.616..452L
  |access-date = 4 February 2023
  |archive-date = 7 March 2023
  |archive-url = https://web.archive.org/web/20230307161053/https://assets.researchsquare.com/files/rs-2292349/v1/34562254-db7b-4289-a7ff-238159687528.pdf?c=1669139626
  |url-status = dead
  }}</ref>

<ref name="Thomas2023">{{cite journal
  |display-authors = etal
  |first1 = Cristina A. |last1 = Thomas
  |first2 = Shantanu P. |last2 = Naidu
  |first3 = Peter |last3 = Scheirich
  |first4 = Nicholas A. |last4 = Moskovitz
  |first5 = Petr |last5 = Pravec
  |first6 = Steven R. |last6 = Chesley
  |title = Orbital Period Change of Dimorphos Due to the DART Kinetic Impact
  |url = https://www.nature.com/articles/s41586-023-05805-2.epdf?sharing_token=YRh4Eyy6C_2rY32dpDWMvNRgN0jAjWel9jnR3ZoTv0OS4WTElJ09_qri44_z5vPAUIL35_x93QgSDpbGEI6I_LlAizV8gHKjsImCQvUx_50In4IPkBHazpDPqxuNXD9WyXWinLOOxBZC5G8JwgQfps4vO2hNNkv759PcDRrAPBRopiwNeXeZ7XJI-ROdYjsUimVD-CGdugWclBklYFE7i1qL5SHhTjNywsuBNmZk0DeQv3-zIOCOfCCnmxTq29F4yJEBe_3fWCBg3_2rJxqGCw%3D%3D&tracking_referrer=www.space.com
  |journal = Nature
  |date = March 2023
  |volume = 616 |issue = 7957 |pages = 448–451 |doi = 10.1038/s41586-023-05805-2
  |pmid = 36858072 |pmc = 10115635 |arxiv = 2303.02077
  |bibcode = 2023Natur.616..448T}}</ref>

<ref name="PDC-Naidu2023">{{cite conference
  |display-authors = etal
  |first1 = Shantanu P. |last1 = Naidu
  |first2 = Steven R. |last2 = Chesley
  |first3 = Nick |last3 = Moskovitz
  |first4 =  Lance A. M. |last4 = Benner
  |first5 = Marina |last5 = Brozovic
  |first6 = Petr |last6 = Pravec
  |title = Change in the mutual orbit of Dimorphos due to the DART impact
  |url = https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/fa5dcb20a6424c088ae2cc7b89a60964
  |conference = 8th IAA Planetary Defense Conference
  |location = Vienna, Austria
  |date = 2 April 2023
  |pages = 17
  |archive-url = https://web.archive.org/web/20230404230925/https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/fa5dcb20a6424c088ae2cc7b89a60964
  |archive-date = 4 April 2023
  |url-status= live}}</ref>

<ref name="Horizons-orbitchange">{{cite web
  |title      = Horizons Batch showing Dimorphos orbital elements on epochs 2022-Sep-26 23:15 (pre-impact) to 2022-Sep-26 23:16 (post-impact)
  |url        = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27Dimorphos%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%272022-09-26%2023:15%27&STOP_TIME=%272022-09-26%2023:16%27&STEP_SIZE=%271%20minute%27&CENTER=%27@20065803%27&OUT_UNITS=%27KM-D%27
  |work       = [[JPL Horizons On-Line Ephemeris System|JPL Horizons]]
  |publisher  = Jet Propulsion Laboratory 
  |accessdate = 24 March 2023}}</ref>

<ref name="Scheirich2023">{{cite conference
  |first1 = P. |last1 = Scheirich
  |first2 = P. |last2 = Pravec
  |title      = Post-Impact Mutual Orbit of the Didymos Binary System Derived from Photometry 
  |url        = https://www.hou.usra.edu/meetings/acm2023/pdf/2050.pdf
  |conference = Asteroids, Comets, Meteors Conference 2023
  |publisher  = Lunar and Planetary Institute
  |issue      = 2851
  |date       = June 2023}}</ref>

<ref name="Pravec2023">{{cite conference
  |display-authors = etal
  |first1 = P. |last1 = Pravec
  |first2 = P. |last2 = Scheirich
  |first3 = A. J. |last3 = Meyer
  |first4 = H. F. |last4 = Agrusa
  |first5 = R. |last5 = Nakano
  |first6 = M. |last6 = Hirabayashi
  |title      = Dimorphos's Post-Impact Lightcurves and Constraints on Its Post-Impact Spin State and Shape
  |url        = https://www.hou.usra.edu/meetings/acm2023/pdf/2052.pdf
  |conference = Asteroids, Comets, Meteors Conference 2023
  |publisher  = Lunar and Planetary Institute
  |issue      = 2851
  |date       = June 2023}}</ref>

<ref name="Fodde2023">{{cite arXiv
  |display-authors = etal
  |first1     = Iosto |last1 = Fodde
  |first2     = Jinglang |last2 = Feng
  |first3     = Massimiliano |last3 = Vasile
  |first4     = Jesús |last4 = Gil-Fernández
  |title      = Design and Analysis of Robust Ballistic Landings on the Secondary of a Binary Asteroid
  |class      = astro-ph.IM
  |date       = October 2023
  |eprint      = 2310.19844}}</ref>

}}

== External links ==
* {{commonscatinline}}

{{2022 in space}}
{{Solar System moons (compact)}}

[[Category:Asteroid satellites]]
[[Category:Named minor planets]]
[[Category:Radar-imaged asteroids]]
[[Category:Active asteroids]]
[[Category:Astronomical objects discovered in 2003]]
[[Category:Minor planets visited by spacecraft]]