Production Rates for the Stardust Mission Target: 81P/Wild 2

Fink, Uwe; Hicks, M.; Fevig, Ronald

doi:10.1006/icar.1999.6182

Cited by 42 publications

(51 citation statements)

References 10 publications

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“…The slopes of all other profiles are >−1.5, hence within the limits for a steady-state coma distorted by solar radiation pressure. The values of December 1996 and April 1997 are consistent with those resulting from similar observations of this comet obtained between February and June 1997 (Fink et al 1999). …”

Section: Coma Profilessupporting

confidence: 88%

“…It is well known that the use of different models (Vectorial versus Haser Model in most cases) and different lifetimes/scalelengths leads to systematic, model dependent differences between the resulting production rates. We have compared our values of 3 April 1997 with those obtained for 2 April 1997 by Fink et al (1999) who determined production rates of CN, C 2 , and NH 2 from different emission bands (CN: 9100 Å, C 2 : 5520 Å, NH 2 : 6335 Å) and using the Haser model with considerably different scalelengths. Both data sets show large differences, particularly in the CN and the NH 2 production rate for which Fink et al (1999) determined values that are higher by factors of ∼2.5, and ∼5, respectively.…”

Section: Spectramentioning

confidence: 99%

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Characterization of STARDUST target comet 81P/Wild 2 from 1996 to 1998

Schulz

Stüwe

Boehnhardt

et al. 2003

A&A

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Abstract. We present the results of our monitoring of comet 81P/Wild 2, the target of the S mission. Broad-band filter images and medium resolution spectra of this comet obtained along its pre-and postperihelion orbit between 1996 and 1998 were analysed in terms of coma morphology and activity. The morphological coma investigation revealed the presence of longlasting fan structures, which remained essentially unchanged for at least three months. The (B − V) and (V − R) colour indices were determined at three different positions along the orbit. The two-dimensional analysis showed a uniform colour over the entire coma. Hence, the material composing the structures is not different from that of the underlying coma. The distribution of coma brightness as a function of projected distance from the nucleus shows no peculiarities. The evolution of the comet's activity during the pre-and postperihelion phase appears to be asymmetric in that activity increases faster preperihelion than it decreases postperihelion. The production rates (or their upper limits in the case on a non-detection) of CN, C 2 , C 3 , and NH 2 were determined from the spectrophotometric observations and compared to other values published in the literature.

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Section: Coma Profilessupporting

confidence: 88%

Section: Spectramentioning

confidence: 99%

Characterization of STARDUST target comet 81P/Wild 2 from 1996 to 1998

Schulz

Stüwe

Boehnhardt

et al. 2003

A&A

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“…The average value in this work (Table 3) is -0.45 ± 0.13, which would place Wild 2 in the "depleted" category according to this taxonomic classification. However, the value is about four times lower than the mean value for depleted comets but is similar to the average value (-0.58 ± 0.15) estimated by Fink et al (1999), which was measured to be (-0.34 ± 0.17) by Farnham et al (2005). The data of log [Q(C 2 )/Q(CN)] for the interval from 1978 to 2010 is plotted in Fig.…”

Section: Compositionsupporting

confidence: 72%

Physical studies of 81P/Wild 2 from the last two apparitions

Lin

Lara

Vincent

et al. 2012

A&A

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Context. We downloaded data for the comet 81P/Wild 2 for May and June 2004 from the ESO archive and monitored this comet from January to August 2010 during its 6th perihelion passage since its discovery in 1978. Photometric data were used to monitor the comet's gas and dust activity as a function of heliocentric distance. Non-photometric data were used for an analysis of the evolution of the dust coma morphology. Aims. The goal of the analysis of the observational data was to characterize the evolution of the cometary activity as the nucleus approaches the Sun. We also aimed to assess the gas and dust production rates for the last two apparitions and investigated the evolution of the dust coma morphology during the last passage in 2010. Methods. The long-slit spectra data were acquired with the EFOSC2 instrument mounted at the 3.6. m ESO telescope in Chile, while narrowband and broadband images were obtained using the 1-m telescope at the Lulin Observatory in Taiwan. Image enhancing techniques were used to investigate the evolution of the dust coma morphology in the R-broadband images, and we modeled the evolution of these dust jets. Where possible, we studied the dust and gas production rate, and the radial profiles of the dust brightness in the Sun-anti-sunward directions.Results. The morphological analysis helped us to detect the jet structures in the dust coma by using the Larson-Sekanian filter. In May 2004, only one feature had been found on the sunward side. In 2010, one of the jet features had been switched-off after January, and at least four new jets were found from April to May. The physical properties show an average reddening between 4420 Å and 6840 Å of 8.4% per 1000 Å and the average resulting log of the C 2 -to-CN production rate ratio is -0.454 ± 0.13, which would place Wild 2 in the "depleted" category according to the taxonomic classification. The slope of the radial dependence of the gas production rates for CN and C 2 is very consistent with observations of many other Jupiter-family comets. The slopes of the surface brightness lie between 0.98 and 1.38 in the images taken at the Lulin observatory, whose the range interval from 2000 km to 30 000 km is roughly consistent with the ρ −1 law. However, the gradient of the radial profile in the sunward direction in the outer region (4.0 ≤ log ρ(km) ≤ 4.5) is slightly steeper than that in the inner region (3.3 ≤ log ρ(km) ≤ 4.0).

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“…Farnham & Schleicher (2005) found a reddening of 36 ± 23% in the green-ultraviolet and 20 ± 10% in the green-blue ranges during the 1983/84 and 1997 apparitions. Moreover, the authors reported colors extracted from reflectance spectra obtained by Fink et al (1999) in 1997 (9-16% between 5300 and 9800 Å).…”

Section: Dust Colorsmentioning

confidence: 99%

“…To support the Stardust mission, 81P was the target of an extensive observational campaign before the spacecraft encounter, which made this object one of the best-known comets in science (Fink et al 1999;Mäkinen et al 2001;Hanner & Hayward 2003;Ishiguro et al 2003;Schulz et al 2003;Sekanina 2003;Farnham & Schleicher 2005;Ferrín 2007).…”

Section: Introductionmentioning

confidence: 99%

Photometric observations of comet 81P/Wild 2 during the 2010 perihelion passage

Bertini

Barbieri

et al. 2012

A&A

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Context. The Jupiter-family comet 81P/Wild 2, target of the NASA Stardust mission, is very important in the context of the studies of pristine objects in the solar system. First, it was only recently deflected into the present orbit, having spent at least 300 yr at higher heliocentric distance prior to the orbital change in 1974. It is therefore likely that the comet experienced a recent activation with consequent low alteration of its original material. Second, it is the only comet whose coma material was brought back to Earth for laboratory analysis. We observed the object between 2010 February 9 and September 9 for a total of 11 nights during the 2010 perihelion passage. Aims. The goals of the campaign were the characterization of the comet's dust activity and the comparison with previous apparitions to derive hints on the secular behavior of the object. Methods. Broadband R-and I-images were acquired using three instruments: ALFOSC, CAMELOT, and TCP. The first one is mounted at the Nordic Optical Telescope on La Palma, while the second and the third are mounted at the Instituto de Astrofisica de Canarias 0.82-m telescope on Tenerife. We analyzed the presence and variability of dust structures in the coma with image-enhancing techniques, the radial profile of the dust brightness, and we measured the dust production rate and the dust reddening. Results. We found evidence of a long-lasting sunward fan and anti-solar tail activity throughout all our observations up to a heliocentric distance of 2.42 AU. A f ρ measurements suggest a pre-perihelion peak of the activity, caused by a seasonal effect, plus two post-perihelion outbursts. Both spatial and A f ρ radial profiles indicate a steady-state coma at nucleocentric distances greater than ∼1000-2000 km. The color analysis reveals a moderately reddened dust with a 6-9%/1000 Å reddening, consistent with the current picture of cometary dust. The second outburst emitted dust with lower reddening. Conclusions. The comparison with previous perihelion passages points toward a recurrent main activity always driven by the same areas on the nucleus, producing dust with similar characteristics and in similar coma structures in different years. Our A f ρ measurement at the longest heliocentric distance suggests the comet was less dust-productive in 2010, pointing toward a possible secular aging of the object and its activity. The change of dust colors during the unusual second outburst suggests that an internal part of the nucleus has different physical properties compared with those that produce the recurrent main activity, pointing toward a heterogeneous comet.

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Production Rates for the Stardust Mission Target: 81P/Wild 2

Cited by 42 publications

References 10 publications

Characterization of STARDUST target comet 81P/Wild 2 from 1996 to 1998

Characterization of STARDUST target comet 81P/Wild 2 from 1996 to 1998

Physical studies of 81P/Wild 2 from the last two apparitions

Photometric observations of comet 81P/Wild 2 during the 2010 perihelion passage

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