Editing Comet Shoemaker–Levy 9 (section)

== Longer-term effects ==
[[File:Subtle Ripples in Jupiter's Rings by Galileo PIA13893 modest.jpg|thumb|Ripples in the rings of Jupiter seen by Galileo spacecraft, caused by Shoemaker-Levy 9]]
The visible scars from the impacts could be seen on Jupiter for many months. They were extremely prominent, and observers described them as more easily visible than the [[Great Red Spot]]. A search of historical observations revealed that the spots were probably the most prominent transient features ever seen on the planet, and that although the Great Red Spot is notable for its striking color, no spots of the size and darkness of those caused by the SL9 impacts had ever been recorded before, or since.<ref name="Hockey">{{cite journal |last=Hockey |first=T.A. |year=1994 |title=The Shoemaker–Levy 9 Spots on Jupiter: Their Place in History |journal= Earth, Moon, and Planets |doi=10.1007/BF00612878 |volume=66 |issue=1 |pages=1–9 |bibcode=1994EM&P...66....1H|s2cid=121034769 }}</ref>

The impact produced many new species in the stratosphere of Jupiter. Long-lasting species are [[Water vapor|H<sub>2</sub>O]], [[Carbon monoxide|CO]], [[Carbon monosulfide|CS]] and [[Hydrogen cyanide|HCN]].<ref name=":0">{{Cite journal |last1=Rodríguez-Ovalle |first1=Pablo |last2=Fouchet |first2=Thierry |last3=Cavalié |first3=Thibault |last4=Lellouch |first4=Emmanuel |last5=Fletcher |first5=Leigh N. |last6=Harkett |first6=Jake |last7=Hue |first7=Vincent |last8=Benmahi |first8=Bilal |last9=Pater |first9=Imke de |date=2025-04-01 |title=JWST observations of exogenic species on Jupiter: HCN, H2O, and CO2 |url=https://www.aanda.org/articles/aa/full_html/2025/04/aa53575-24/aa53575-24.html |journal=Astronomy & Astrophysics |language=en |volume=696 |pages=A173 |bibcode=2025A&A...696A.173R |doi=10.1051/0004-6361/202453575 |issn=0004-6361|doi-access=free }}</ref> H<sub>2</sub>O emission was monitored between 2002 and 2019 with the [[Odin (satellite)|Odin Space Telescope]] and showed a linear decline.<ref>{{Cite journal |last1=Benmahi |first1=B. |last2=Cavalié |first2=T. |last3=Dobrijevic |first3=M. |last4=Biver |first4=N. |last5=Bermudez-Diaz |first5=K. |last6=Sandqvist |first6=Aa |last7=Lellouch |first7=E. |last8=Moreno |first8=R. |last9=Fouchet |first9=T. |last10=Hue |first10=V. |last11=Hartogh |first11=P. |last12=Billebaud |first12=F. |last13=Lecacheux |first13=A. |last14=Hjalmarson |first14=Å |last15=Frisk |first15=U. |date=2020-09-01 |title=Monitoring of the evolution of H2O vapor in the stratosphere of Jupiter over an 18-yr period with the Odin space telescope |url=https://www.aanda.org/articles/aa/full_html/2020/09/aa38188-20/aa38188-20.html |journal=Astronomy & Astrophysics |language=en |volume=641 |pages=A140 |arxiv=2007.05415 |bibcode=2020A&A...641A.140B |doi=10.1051/0004-6361/202038188 |issn=0004-6361}}</ref> Spectroscopic observers found that [[ammonia]] and [[carbon disulfide]] (CS<sub>2</sub>) persisted in the atmosphere for at least fourteen months after the collisions, with a considerable amount of ammonia being present in the stratosphere as opposed to its normal location in the troposphere.<ref name="McGrath 2">{{cite journal |last1=McGrath |first1=M.A. |date=September 1996 |title=Long-term Chemical Evolution of the Jupiter Stratosphere Following the SL9 Impacts |journal=Bulletin of the American Astronomical Society |volume=28 |page=1149 |bibcode=1996DPS....28.2241M |last2=Yelle |first2=R. V. |last3=Betremieux |first3=Y.}}</ref> CS was detected 19 years after the impact with the [[Atacama Submillimeter Telescope Experiment]] in the atmosphere of Jupiter. The CS total mass showed a 90% decrease.<ref>{{Cite journal |last1=Iino |first1=T. |last2=Ohyama |first2=H. |last3=Hirahara |first3=Y. |last4=Takahashi |first4=T. |last5=Tsukagoshi |first5=T. |date=2016-11-22 |title=SUBMILLIMETER OBSERVATION OF JUPITER'S STRATOSPHERIC COMPOSITION: DETECTION OF CARBON MONOSULFIDE (J = 7 − 6) 19 YEARS AFTER THE COMETARY IMPACT |journal=The Astronomical Journal |language=en |volume=152 |issue=6 |pages=179 |arxiv=1610.02802 |bibcode=2016AJ....152..179I |doi=10.3847/0004-6256/152/6/179 |doi-access=free |issn=0004-6256 }}</ref>

The new species can help to reveal the processes in Jupiter’s [[aurora]]. [[Atacama Large Millimeter Array|ALMA]] did detect CO and HCN. In and near the auroral region HCN was depleted. Chemical processes bonds HCN on large aurora-produced [[Aerosol|aerosols]].<ref>{{Cite journal |last1=Cavalié |first1=T. |last2=Rezac |first2=L. |last3=Moreno |first3=R. |last4=Lellouch |first4=E. |last5=Fouchet |first5=T. |last6=Benmahi |first6=B. |last7=Greathouse |first7=T. K. |last8=Sinclair |first8=J. A. |last9=Hue |first9=V. |last10=Hartogh |first10=P. |last11=Dobrijevic |first11=M. |last12=Carrasco |first12=N. |last13=Perrin |first13=Z. |date=September 2023 |title=Evidence for auroral influence on Jupiter's nitrogen and oxygen chemistry revealed by ALMA |url=https://ui.adsabs.harvard.edu/abs/2023NatAs...7.1048C/abstract |journal=Nature Astronomy |language=en |volume=7 |issue=9 |pages=1048–1055 |arxiv=2407.07385 |bibcode=2023NatAs...7.1048C |doi=10.1038/s41550-023-02016-7 |issn=2397-3366}}</ref> [[James Webb Space Telescope|JWST]] observations from December 2022 did detect an increase of H<sub>2</sub>O in the south polar region, while [[Carbon dioxide|CO<sub>2</sub>]] is depleted. This is seen as an exchange of [[oxygen]] between the two molecules in the southern auroral region. HCN is also depleted towards the south polar region.<ref name=":0" />

Atmospheric temperature dropped to normal levels much more quickly at the larger impact sites than at the smaller sites: at the larger impact sites, temperatures were elevated over a region {{convert|15000|to|20000|km|abbr=on}} wide, but dropped back to normal levels within a week of the impact. At smaller sites, temperatures 10 K (10 '''°'''C; 18 '''°'''F) higher than the surroundings persisted for almost two weeks.<ref name="Bézard">{{cite journal |last=Bézard |first=B. |date=October 1997 |title=Long-term Response of Jupiter's Thermal Structure to the SL9 Impacts |journal=Planetary and Space Science |volume=45 |issue=10 |pages=1251–1271 |doi=10.1016/S0032-0633(97)00068-8 |bibcode=1997P&SS...45.1251B}}</ref> Global stratospheric temperatures rose immediately after the impacts, then fell to below pre-impact temperatures 2–3&nbsp;weeks afterwards, before rising slowly to normal temperatures.<ref name="Moreno">{{cite journal |last1= Moreno|first1=R.|date=June 2001 |title= Jovian Stratospheric Temperature during the Two Months Following the Impacts of Comet Shoemaker–Levy 9|journal=Planetary and Space Science |volume=49 |issue=5 |pages=473–486 |doi=10.1016/S0032-0633(00)00139-2 |bibcode=2001P&SS...49..473M |last2= Marten |first2= A |last3= Biraud |first3= Y |last4= Bézard |first4= B |last5= Lellouch |first5= E |last6= Paubert |first6= G |last7= Wild |first7= W}}</ref>

Comet Shoemaker-Levy 9 also did cause ripples in the [[Rings of Jupiter|ring system of Jupiter]], which were first observed with [[Galileo (spacecraft)|Galileo]] and later with [[New Horizons]] 13 years later the rings still show ripples, suggesting that subsequent events may have also tilted the rings.<ref>{{Cite journal |last1=R. |first1=Showalter, Mark |last2=M. |first2=Hedman, Matthew |last3=A. |first3=Burns, Joseph |date=May 2011 |title=The Impact of Comet Shoemaker-Levy 9 Sends Ripples Through the Rings of Jupiter |url=https://ui.adsabs.harvard.edu/abs/2011Sci...332..711S/abstract |journal=Science |language=en |volume=332 |issue=6030 |pages=711–713 |bibcode=2011Sci...332..711S |doi=10.1126/science.1202241 |pmid=21454755 |issn=0036-8075 |archive-url=http://web.archive.org/web/20240906175924/https://ui.adsabs.harvard.edu/abs/2011Sci...332..711S/abstract |archive-date=2024-09-06}}</ref> Additionally it is predicted that the comet could have formed a new ring around Jupiter.<ref>{{Cite journal |last=Horanyi |first=Mihaly |date=December 2024 |title=Did SL9 Leave Behind a New Jovian Ring? |url=https://ui.adsabs.harvard.edu/abs/2024AGUFMNH43D2442H/abstract |journal=AGU Fall Meeting 2024 |issue=2442 |bibcode=2024AGUFMNH43D2442H}}</ref>