Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Keller, H. U.; Küppers, M.; Fornasier, S.; Gutiérrez, P. J.; Hviid, S. F.; Jordá, L.; Knollenberg, J.; Lowry, S. C.; Rengel, Miriam; Bertini, Ivano; Cremonese, G.; Ip, W. H.; Koschny, D.; Kramm, R.; Kührt, Ekkehard; Lara, L. M.; Sierks, H.; Thomas, N.; Barbieri, C.; Lamy, Philippe; Rickman, H.; Rodrigo, R.; A’Hearn, Michael F.; Angrilli, Francesco; Barucci, M. A.; Bertaux, Jean-Loup; Deppo, Vania Da; Davidsson, B.; Cecco, M. De; Debei, S.; Fulle, M.; Gliem, F.; Groussin, O.; Moreno, J. J. Lopez; Marzari, F.; Naletto, G.; Sabau, L.; Andrés, Ángel Sanz; Wenzel, K.‐P.

doi:10.1016/j.icarus.2006.09.028

Cited by 17 publications

(19 citation statements)

References 25 publications

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“…The detection of flux from dust grains so soon after impact implies that if material from the impact traveled into the offset beam in about 10 min, the dust would have to have been moving at a speed of 700 m/s. This speed is consistent with the fastest material seen by other investigators Keller et al, 2007). The faster decrease of submicron sized amorphous carbon grain mass in the centered positions also supports the conclusion that the carbon grains are traveling at a greater speed than the amorphous olivine grains.…”

Section: Temporal Evolution Of the Dust Masssupporting

confidence: 90%

Gemini-N mid-IR observations of the dust properties of the ejecta excavated from Comet 9P/Tempel 1 during Deep Impact

Harker

Woodward

Wooden

et al. 2007

Icarus

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We present mid-infrared spectra and images from the Gemini-N (+MICHELLE) observational campaign of Comet 9P/Tempel 1 before, during, and after its encounter with Deep Impact. We use our thermal grain model to probe the 10 µm properties of the dust grains in the coma of the comet. Before impact (3 July 2005 UT), and more than 24 h after impact (5, 16, and 28 July 2005 UT), the comet dust grains were composed mostly of amorphous olivine, and were relatively large (peak of the grain size distribution a p = 0.7-1.5 µm). For the night of impact, we extract spectra by centering on the nucleus, and offset 1 from the nucleus in the direction of the impact ejecta plume. We find small dust grains (∼0.2 µm) of a diverse mineralogy (amorphous olivine, amorphous pyroxene, amorphous carbon, and crystalline olivine) populating the ejecta. The submicron sized dust grains move faster than the other, larger grains ( 0.7 µm), with amorphous olivine and amorphous carbon traveling together, and amorphous pyroxene and crystalline olivine dispersing at a similar rate. Deriving a velocity law from a time-of-flight analysis, we find that the material traveled with a velocity law scaled by v 0.2 µm = 220 ± 20 m s −1 and with a power of p = 0.5. This velocity power-law requires a sustained release of grains for the duration of 45-60 min after impact. Since the mineral species are traveling at different speeds, and there was a sustained release of grains due to a possible "gas-plume," we conclude that the different minerals did not originate from grain aggregates destroyed by the impact, but instead arise from an inhomogeneous nucleus.

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Section: Temporal Evolution Of the Dust Masssupporting

confidence: 90%

Gemini-N mid-IR observations of the dust properties of the ejecta excavated from Comet 9P/Tempel 1 during Deep Impact

Harker

Woodward

Wooden

et al. 2007

Icarus

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“…Richardson et al (2007) find that the excavated mass in the DI impact ranged from 10 5 to 10 7 kg depending on the assumed strength of the surface material. However, other observations yield 4.5-9 × 10 6 kg (Keller et al, 2007) and 1.3 × 10 7 kg (Schleicher et al, 2006) for the mass of H 2 O ice released during the impact. This suggests ∼10 6 kg for a large mini-outburst.…”

Section: The Observed and Inferred Basis Of The Modelmentioning

confidence: 92%

Cometary cryo-volcanism: Source regions and a model for the UT 2005 June 14 and other mini-outbursts on Comet 9P/Tempel 1

Belton

Feldman

A’Hearn

et al. 2008

Icarus

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“…It was the first reported in situ observation of a cometary outburst. Images taken by the Wide Angle Camera (WAC) of the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS; Keller et al 2007) on board Rosetta showed an increase of two orders of magnitude in the 67P coma surface brightness between 0940 and 1010 UT. An overview of the multi-instrument observations of the outburst can be found in Grün et al (2016).…”

Section: Introductionmentioning

confidence: 99%

Impact of a cometary outburst on its ionosphere

Hajra¹,

Henri²,

Vallières³

et al. 2017

A&A

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We present a detailed study of the cometary ionospheric response to a cometary brightness outburst using in situ measurements for the first time. The comet 67P/Churyumov-Gerasimenko (67P) at a heliocentric distance of 2.4 AU from the Sun, exhibited an outburst at ∼1000 UT on 19 February 2016, characterized by an increase in the coma surface brightness of two orders of magnitude. The Rosetta spacecraft monitored the plasma environment of 67P from a distance of 30 km, orbiting with a relative speed of ∼0.2 m s −1 . The onset of the outburst was preceded by pre-outburst decreases in neutral gas density at Rosetta, in local plasma density, and in negative spacecraft potential at ∼0950 UT. In response to the outburst, the neutral density increased by a factor of ∼1.8 and the local plasma density increased by a factor of ∼3, driving the spacecraft potential more negative. The energetic electrons (tens of eV) exhibited decreases in the flux of factors of ∼2 to 9, depending on the energy of the electrons. The local magnetic field exhibited a slight increase in amplitude (∼5 nT) and an abrupt rotation (∼36.4• ) in response to the outburst. A weakening of 10-100 mHz magnetic field fluctuations was also noted during the outburst, suggesting alteration of the origin of the wave activity by the outburst. The plasma and magnetic field effects lasted for about 4 h, from ∼1000 UT to 1400 UT. The plasma densities are compared with an ionospheric model. This shows that while photoionization is the main source of electrons, electron-impact ionization and a reduction in the ion outflow velocity need to be accounted for in order to explain the plasma density enhancement near the outburst peak.

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Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Cited by 17 publications

References 25 publications

Gemini-N mid-IR observations of the dust properties of the ejecta excavated from Comet 9P/Tempel 1 during Deep Impact

Gemini-N mid-IR observations of the dust properties of the ejecta excavated from Comet 9P/Tempel 1 during Deep Impact

Cometary cryo-volcanism: Source regions and a model for the UT 2005 June 14 and other mini-outbursts on Comet 9P/Tempel 1

Impact of a cometary outburst on its ionosphere

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