SL-9 Fragments A, E, H, L, Q1 Collision Onto Jupiter: Mid-Infrared Light Curves

Lagage, Pierre-Olivier; Galdemard, P.; Pantin, É.; Jouan, R.; Massé, Pierre; Sauvage, M.; Olofsson, G.; Huldtgren, M.; Belmonte, Juan Antonio; Régulo, C.; Espinosa, J. M. Rodríguez; Vidal, Luciano N.; Mosser, B.; Gautier, D.

doi:10.1017/s1539299600012363

Cited by 3 publications

(11 citation statements)

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“…The extensive series of 2.3 /xm lightcurves obtained at Siding Spring (McGregor et al 1995; see Fig. 3), and the similar series of 12 /im lightcurves obtained at La Palma (Lagage et al 1995; see Fig. 4), demonstrate conclusively that the main event began ~ 6 min after the impact time in all cases, irrespective of the distance of the impact point behind the limb.…”

Section: P D Nicholson: Impact Phenomena 97mentioning

confidence: 51%

“…Color temperatures derived from 2.3/3.1 /im flux ratios during the latter part of the H second precursor are 900-1300 K (Hamilton et al 1995), while during the equivalent phase of the R impact the 2.3/4.5 um color temperature slowly increased from 650 K at Ti + 1 min to 850 K at T + 3.5 min. Spanning a wider wavelength range, measurements of the H and L precursor peaks at 10 and 12 /im (Livengood et al 1995;Lagage et al 1995) combined with data at at 2.3 /im imply similar color temperatures of 600-625 K.…”

Section: Second Precursor (Rising Fireball)mentioning

confidence: 97%

“…A similar wavelength-dependence is shown by the H impact, where the flux was observed to drop more sharply after the second precursor at 3.1 /xm than at 2.3 /xm . Mid-IR observations of the H and L impacts show second precursors for these events at 10-12 /xm, which also faded after 30-60 sec (Livengood et al 1994;Lagage et al 1995) in contrast to their persistence at 2.3 /xm.…”

Section: Second Precursormentioning

confidence: 99%

“…These data include examples of large, medium-size and small impacts, and in addition to precursors for events C, D, G, K and W, the lightcurves show prominent shoulders for C, D and G. (The lightcurves for the later impacts were followed only through the main peak.) Figure 4, from Lagage et al (1995), presents a series of mid-IR lightcurves for the A, E, H, L and Ql impacts obtained with the 10 /xm CAMIRAS camera at the 2.6 m Nordic Optical Telescope at La Palma, in the Canary Islands. Impacts F, P2, Q2, T and U were not detected.…”

Section: Lightcurve Comparisonsmentioning

confidence: 99%

“…However, Colas et al (1995) find that the L precursor peaked ~ 15 sec later at 2.12 /xm than at 1.25 or 1.65 /xm. Drossart et al (1995) and Lagage et al (1995) note a 30 sec delay between the onset of the second L precursor at 2.3 /xm and at 12 /xm, although the second H precursor seems to have been seen essentially simultaneously at 2.3 /xm and at 10 /xm (Livengood et, al. 1994).…”

Section: Second Precursormentioning

confidence: 99%

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Earth-based observations of impact phenomena

Nicholson

1996

International Astronomical Union Colloquium

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Earth-based observations at near- and mid-infrared wavelengths were obtained for at least 15 of the SL9 impacts, ranging from the spectacular G, K and L events to the barely-detected N and V impacts. Although there were a few exceptions, most of the IR lightcurves fit a common pattern of one or two relatively faint precursor flashes, followed several minutes later by the main infrared event as the explosively-ejected plume crashed down onto the jovian atmosphere. Correlations with the impact times recorded by the Galileo spacecraft and plumes imaged by the Hubble Space Telescope lead to an interpretation of the twin precursors in terms of (i) the entry of the bolide into the upper atmosphere, and (ii) the re-appearance of the rising fireball above Jupiter's limb. Positive correlations are observed between the peak IR flux observed during the splashback phase and both pre-impact size estimates for the individual SL9 fragments and the scale of the resulting ejecta deposits. None of the fragments observed to have moved off the main train of the comet by May 1994 produced a significant impact signature. Earth-based fireball temperature estimates are on the order of 750 K, 30-60 sec after impact. For the larger impacts, the unexpectedly protracted fireball emission at 2.3 μm remains unexplained. A wide range of temperatures has been inferred for the splashback phase, where shocks are expected to have heated the re-entering plume material at least briefly to several thousand K, and further modelling is required to reconcile these data.

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Section: P D Nicholson: Impact Phenomena 97mentioning

confidence: 51%

Section: Second Precursor (Rising Fireball)mentioning

confidence: 97%

Section: Second Precursormentioning

confidence: 99%

Section: Lightcurve Comparisonsmentioning

confidence: 99%

Section: Second Precursormentioning

confidence: 99%

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Earth-based observations of impact phenomena

Nicholson

1996

International Astronomical Union Colloquium

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Optical imaging of the impact plume on Jupiter from fragment L of comet D/Shoemaker-Levy 9

Fitzsimmons

Andrews

Catchpole

et al. 1996

Monthly Notices of the Royal Astronomical Society

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We report optical CCD imaging and photometry of the impact plume on Jupiter resulting from the destruction of fragment L of DjShoemaker-Levy 9. The plume appears resolved in several frames, with the largest dimensions appearing similar to those of other plumes imaged by HST. The light curve and timings are consistent with an ejection velocity for the plume material of v=:: 20 km S -1. The plume itself was detected by reflected sunlight from dust grains, and the observed fluxes are consistent with an optically thick plume composed of silicates. A large flare in the light curve was observed -7 min after the initial maximum, the cause of which is unclear.

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Comet Shoemaker‐Levy 9 Fragment Size Estimates: How Big Was the Parent Body?^a

Crawford

1997

Annals of the New York Academy of Sciences

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The impact of Comet Shoemaker-Levy 9 on Jupiter in July, 1994 was the largest, most energetic impact event on a planet ever witnessed. Because it broke up during a close encounter with Jupiter in 1992. it was bright enough to be discovered more than a year prior to impact, allowing the scientific community an unprecedented opportunity to assess the effects such an event would ha\7e. Many excellent observations were made from Earth-based telescopes, the Hubble Space Telescope (HST) and the Galileo spacecraft en route to Jupiter. In this paper, these observations are used in conjunction with computational simulations performed with the CTH shock-physics hydrocode to determine the sizes of the fifteen fragments that made discernible impact features on the planet. To do this, CTH was equipped with a radiative ablation model and a post-processing radiative ray-trace capability that enabled light-flux predictions (often called the impact flash) for the viewing geometries of Galileo and ground-based observers. The five events recorded by Galile0 were calibrated to give fragment size estimates. Compared against ground-based and HST observations, these estimates were extended using a least-squares analysis to assess the impacts of the remaining ten fragments. Some of the largest impacts (L, G and K) were greater that 1 km in diameter but the density of the fragments was low, about 0.25 g/cm3. The volume of the combined fifteen fragments would make a sphere 1.8 km in diameter. Assuming a pre-breakup density of 0.5 g/cm3, the parent body of Shoemaker-Levy 9 had a probable diameter of 1.4 km. The total kinetic energy of all the impacts was equivalent to the explosive yield of 300 Gigatons of TNT- In early July, 1992, periodic comet Shoemaker-Levy 9 broke up during a close encounter with Jupiter. For a brief two year period, about 20 large fragments and associated debris followed one last orbit about Jupiter before striking the planet at an estimated velocity of 60 kids. The largest fragments entered the Jovian atmosphere during the week of July [16][17][18][19][20][21][22] 1994. Although the impact sites were located just beyond the limb of Jupiter and were not directly visible from Earth, the Galileo spacecraft was positioned for direct viewing of the impact sites. While impact phenomena were not spatially resolved by the spacecraft, its timing, spectral and luminosity data are invaluable for comparison with analytical and numerical models. Fireballs and plumes generated by the impacts were visible in line-of-sight from Earth within a minute ( Fig. 1) and the impact locations themselves rotated into view within 7-20 minutes (Hammel et al., 1995). The wealth of data provided by this fortuitous event gives us an opportunity to assess models of meteoroid entry into planetary atmospheres and, in the context of this paper, to estimate the size of the ShoemakerLevy 9 parent body based on observations of the radiated light flux observed by the Galiledspacecraft and by Earth-based telescopes. The eventual goal of our modeling effo...

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SL-9 Fragments A, E, H, L, Q1 Collision Onto Jupiter: Mid-Infrared Light Curves

Cited by 3 publications

References 0 publications

Earth-based observations of impact phenomena

Earth-based observations of impact phenomena

Optical imaging of the impact plume on Jupiter from fragment L of comet D/Shoemaker-Levy 9

Comet Shoemaker‐Levy 9 Fragment Size Estimates: How Big Was the Parent Body?^a

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SL-9 Fragments A, E, H, L, Q1 Collision Onto Jupiter: Mid-Infrared Light Curves

Cited by 3 publications

References 0 publications

Earth-based observations of impact phenomena

Earth-based observations of impact phenomena

Optical imaging of the impact plume on Jupiter from fragment L of comet D/Shoemaker-Levy 9

Comet Shoemaker‐Levy 9 Fragment Size Estimates: How Big Was the Parent Body?a

Contact Info

Product

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Comet Shoemaker‐Levy 9 Fragment Size Estimates: How Big Was the Parent Body?^a