Small impacts on the Giant Planet Jupiter

Transcription

1 Sall ipacts on the Giant Planet Jupiter Ricardo Hueso 1, Marc Delcroix 2, Agustin Sanchez-Lavega 1, Jose Felix Rojas 1, Josep María Góez-Forrellad 3 & Jon Juaristi-Capillo 1 1 University of the Basque Country, Bilbao (Spain) 2 Societé Astronoique de France (France) 3 Fundació Observatori Esteve Duran, Seva, Spain 49th Meeting of the AAS Division for Planetary Sciences

2 Shoeaker-Levy 9 July 16-23, 1994 A Jupiter faily coet (~ 2 k in diaeter) fragented by gravitational tides resulting in 16 fragent ipacts (6 large ipacts). July 19, 2009: Anthony Wesley discovers an ipact scar in Jupiter At the tie this was coined as a once in a lifetie event Harrington, J., et al. Jupiter book (2004). Size of the ipact object: k Sánchez-Lavega et al. ApJL (2010) (Background: HST iage of the G ipact site) Hael et al., ApJL (2010) Possible asteroidal nature: Orton et al. Icarus (2011)

3 2010: A fireball in Jupiter s atosphere! June 3, 2010 at 20:31:20 UT. Casual Jupiter observation by A. Wesley with a 15 telescope, a 60fps caera & and a red filter. The second ipact in Jupiter found by a single person! Flash ~ 1/6000 Jupiter brightness Equivalent to a +6.5 agnitude star Tie duration about 1 s Flash siultaneously observed by an aateur in Phillipines (Christopher Go) using a 11 telescope, siilar caera and a blue filter. Fast capaign to detect a debris field in the atosphere (HST, VLT, Geini, Keck, IRTF, ). No debris found! Analysis of both light-curves and lack of observable debris Flash caused by an ipact of a 8-13 object releasing x10 13 J of luinous energy Hueso et al. ApJL (2010)

4 since then 4 ore flashes (11 videos & 12 observers) in 8 years June 3, 2010 Anthony Wesley (Australia) Christopher Go (Phillipines) August 22, 2010 Masayuki Tachikawa, Kazuo Aoki, Masayuki Ishiaru (Japan). Septeber 10, 2012 Dan Petersen visual alert and accurate agnitude estiation! Video by George Hall (USA) No detections --- March 17, 2016 Gerrit Kernbauer (Austria) John McKeon (Ireland). May 26, 2017 Sauveur Pedranghelu (France), Thoas Riessler (Gerany), Andre Fleckstein (Gerany). Diversity of telescopes (fro 6 to 14 ), caeras, speeds, filters, seeing,

5 Analysis of flashes light-curves Differential photoetry + Iage calibration using Jupiter integrated flux as a reference Ipacts of objects of sizes: 5-15 releasing energies of ktns (Chelyabinsk ipactlike) Hueso et al., A&A, 2013

6 Ipact on May 26, - Lightcurves exaples Original iage Differential photoetry Average ipact location Ipact location adjusted & Aperture photoetry with background substraction (over an outer ring) + Light-curves in RGB channels in both observations + Additional light-curve fro A. Fleckstein video observations (IR) (all with lower quality and detail)

7 Ipact on May 26, - Energy calibration 1) Integrated photoetry of Jupiter disk + Solar constant at Jupiter s distance: W/ 2 2) Convolution of Solar Spectru+Caera response+jupiter spectru 3) Integrate light-curve (5-20% error) & Geoetric correction Detected Luinous energy Jupiter clouds reflection light Punctual source 4) Coputing the total luinous energy Detected energy into total luinous energy fro the deconvolution of Placnk s black body law with filter and caera responses T BB =[ ] K Factor of 2 uncertainty in energy calculation Earth s fireballs, SL9 ipacts, 2010 Jupiter fireball in R/B filters 5) Fro luinous energy to kinetic energy of the ipactor E 0 Efficiency factor converting kinetic energy to luinous energy where E 0 = luinous energy in ktn (based on observations of Earth bolides). Adapted fro Brown et al. Nature (2002)

8 Results: Energies, Masses & Sizes of all Jupiter fireballs Assuptions on the collision Ipact velocity: v 60 k / s (luinous efficiency) Density: 2.0 g / c 3 Density: 0.6 g / c 3 Ipacts reported in Hueso et al June 3, 2010 Energy ktn Mass Tn 14 J August 20, 2010 Energy ktn Mass Tn 14 J Sept. 10, 2012 (ost intense) Energy ktn Mass Tn 14 J Size (diaeter) D D Size (diaeter) D D Size (diaeter) D D Latest Jupiter ipacts March 17, 2016 May 26, 2017 (sallest ipact) Energy ktn Mass Tn 14 J Energy ktn Mass Tn 14 J Size (diaeter) D D Size (diaeter) D D Chebyalinsk-like events [450 ktn] and 5-60 ties less energetic than Tunguska ( ktn) 1-3x10-6 less than the cobined SL9 ipacts ( ktn)

9 How large ust an object be to leave a visible feature on the planet? HST observations of SL9 ipact debris Galileo light-curves of SL9 fragent ipacts Chapan, GRL, 1995 E/F H Q1 R D/G N Q1 Hael et al., Science, 1995 Extensive nuerical siulations Fragent N had an estiated size of 45 with a ean density of 0.25 g/c 3 Crawford, Annals of the NY Acadey of Science, 1997 SL-9 fragent N: 14 ties ore assive than the largest possible ass for the flash detected in Septeber 2012 or 180 ties ore assive than the sallest flash detected in May 2017.

10 How representative are these flashes of siilar undetected ipacts in Jupiter? Statistical analysis of aateur iages contributed to the PVOL2 database (17643 iages since 2010) Geographical location of observers 21 # Iages fro Low latitudes: 21% # Iages fro North latitudes: 65% # Iages fro South latitudes: 16% The efficiency of detecting ipacts by the aateur counity increases with oppositions oving towards suer in the north heisphere

11 1000 s of Terabytes of Jupiter s observations in the hard-drives of the aateur counity! Differential photoetry of video observations shows the ipacts better than the eye can see Marc Delcroix s DeTeCt 2.1 : Largest effort to find ore ipacts on analysis of video observations Coand line software used by >70 collaborators analyzing >70,000 videos worth 83 days sparsed over a decade Log files of negative detections are later analyzed DeTeCt3.0: UPV/EHU + Marc Delcroix (Funded by Europlanet-2020 RI But ost of the observations are under bad conditions and the software does not find the ipacts in the worst observations.

12 Estiation of the nuber of coparable Jupiter ipacts per year Higher than [4.4] (Detect project) Original estiation in 2013 with 3 flashes fro a qualitative assesent of distribution of observations [5-50] 0 [per year] 2 ipacts in 2 onths in 2010 require a higher flux of ipacts [4.5-45] (sae arguents with 5 ipacts in 8 years) [50] per year Absolute iniu [0.67] [7.5-45] (correction fro bad weather in the Norh heisphere) (6 ipacts in 9 yrs counting the 2009 ipact) Monte-Carlo siulations 1 ipact in 8 years with teporal coverage 25% accuulated (longitudinal distribution of tie of about 400 hrs observers) + 50% weather + A. Wesley & C. Go 50% quality or detection capability [5-15] [22-44] Iprobability of a single observer finding 2 ipacts in 9 years (A. Wesley) 2 ipacts in 400 hours Global estiate: [5-30] We only observe 9/12 onths and 1/3 of the planet total flux of size ipacts per year

13 Updated Flux of ipacts in Jupiter & Conclusions 10 size objects should be detected yearly in the next Jupiter oppositions. A huge flash leaving an observable debris field could be observable in Jupiter every 5-15 years on average when correcting fro the tie we observe Jupiter. Cobined possible sizes of the 5 events An sall debris field caused by the ipact of a size objects could occulr once every 5-10 years and could be detectable once every 7-12 years for about one week for regular aateur observers. Juno s continuous otivation of aateur and professional observers will help to find ore ipacts the next year with a Jupiter opposition on May 9.