The Deep Impact Earth-Based Campaign

Meech, К. J.; A’Hearn, Michael F.; Fernández, Yanga; Lisse, C. M.; Weaver, Harold A.; Biver, Nicolás; Woodney, L. M.

doi:10.1007/s11214-005-3382-8

Cited by 34 publications

(16 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This fraction is much larger than the estimates for Tempel 2 and Arend-Rigaux approximately 1% and <1%, respectively (Millis et al 1988, A'Hearn et al 1989. Based on the compilation of photometry by Meech et al (2005), the first signs of activity of comet Tempel 1 occur between 600 and 400 days before perihelion (4-3 au). Spitzer images of the comet at 478 and 464 days pre-perihelion (3.7 au) show no evidence for near aphelion activity (Lisse et al 2005, Reach et al 2007, and neither do R-band images at 4.2 au postperihelion (Hergenrother et al 2007).…”

Section: Targets Observations and Reductionmentioning

confidence: 71%

Mid-infrared spectra of comet nuclei

Kelley

Woodward

Gehrz

et al. 2017

Icarus

View full text Add to dashboard Cite

Jovian Trojan D-type asteroids have mid-infrared emissivity features strikingly similar to comet comae, suggesting that they have the same compositions and that the surfaces of the Trojans are highly porous. However, a direct comparison between a comet and asteroid surface has not been possible due to the paucity of spectra of comet nuclei at mid-infrared wavelengths. We present 5-35 {\mu}m thermal emission spectra of comets 10P/Tempel 2, and 49P/Arend-Rigaux observed with the Infrared Spectrograph on the Spitzer Space Telescope. Our analysis suggests the spectra are dominated by the comet nucleus. We fit each spectrum with the near-Earth asteroid thermal model (NEATM) and find sizes in agreement with previous values. However, the NEATM beaming parameters of the nuclei, 0.74 to 0.83, are systematically lower than the Jupiter-family comet population mean of 1.03+/-0.11, derived from 16- and 22-{\mu}m photometry. When the spectra are normalized by the NEATM model, a weak 10-{\mu}m silicate plateau is evident, with a shape similar to those seen in mid-infrared spectra of D-type asteroids. We compare, in detail, these comet nucleus emission features to those seen in spectra of the Jovian Trojan D-types (624) Hektor, (911) Agamemnon, and (1172) Aneas, as well as those seen in the spectra of seven comet comae. The comet comae present silicate features with two distinct shapes, either trapezoidal, or more rounded. The surfaces of Tempel 2, Arend-Rigaux, and Hektor best agree with the comae that present trapezoidal features. An emissivity minimum at 15 {\mu}m, present in the spectra of Tempel 2, Arend-Rigaux, Hektor, and Agamemnon, is also described, the origin of which remains unidentified. The compositional similarity between D-type asteroids and comets is discussed, and our data supports the hypothesis that they have similar origins in the early Solar System.Comment: Abridged abstract; 46 pages, 10 figures; Author's accepted manuscript with revised acknowledgement

show abstract

Section: Targets Observations and Reductionmentioning

confidence: 71%

Mid-infrared spectra of comet nuclei

Kelley

Woodward

Gehrz

et al. 2017

Icarus

View full text Add to dashboard Cite

show abstract

“…Thus remote sensing will be important for applying the full range of techniques that astronomers use, from high-speed photometry through high-resolution spectroscopy and at wavelengths from X-ray to radio. The details of the Earth-based program are described by Meech et al (2005) and the role of amateurs in this program is also discussed by McFadden et al (2005).…”

Section: Overview Of the Instruments And The Missionmentioning

confidence: 99%

Deep Impact: A Large-Scale Active Experiment on a Cometary Nucleus

et al. 2005

View full text Add to dashboard Cite

The Deep Impact mission will provide the first data on the interior of a cometary nucleus and a comparison of those data with data on the surface. Two spacecraft, an impactor and a flyby spacecraft, will arrive at comet 9P/Tempel 1 on 4 July 2005 to create and observe the formation and final properties of a large crater that is predicted to be approximately 30-m deep with the dimensions of a football stadium. The flyby and impactor instruments will yield images and near infrared spectra (1-5 µm) of the surface at unprecedented spatial resolutions both before and after the impact of a 350-kg spacecraft at 10.2 km/s. These data will provide unique information on the structure of the nucleus near the surface and its chemical composition. They will also used to interpret the evolutionary effects on remote sensing data and will indicate how those data can be used to better constrain conditions in the early solar system.

show abstract

“…A critical component of such an experiment is to have a detailed understanding of the baseline characteristics of the object, so that effects caused by the impact can be distinguished from normal behavior, such as variations due to the rotation of the nucleus or to orbital motion and changing seasons. Observing campaigns involving hundreds of astronomers were conducted to provide support (Meech et al 2005a(Meech et al , 2005b). Here we report on photometry and imaging of Tempel 1 obtained at Lowell Observatory at and in the days surrounding the Deep Impact event of 2005 July 4, which provide both a baseline and a detailed look at the impact and its aftermath.…”

Section: Introductionmentioning

confidence: 99%

Photometry and Imaging Results for Comet 9P/Tempel 1 andDeep Impact: Gas Production Rates, Postimpact Light Curves, and Ejecta Plume Morphology

Schleicher¹,

Barnes²,

Baugh³

2006

Astron J

106

View full text Add to dashboard Cite

We present Earth-based imaging and photometry results of Deep Impact target comet 9P/Tempel 1 obtained at and in the nights surrounding the time of the spacecraft's impact. These observations establish the baseline behavior of Tempel 1 prior to impact, including a water vaporization rate of 6 ; 10 27 molecules s À1 , thereby enabling us to determine the effects directly caused by this explosive event. The instantaneous fireball was not detected, but a postimpact brightening from ejecta material was prominent and shows evidence of a slowly decreasing optical depth over more than an hour of time. We have successfully reproduced both the general morphology of the ejecta plume and many details of the shape and brightness distribution on successive nights following the impact using a modified Monte Carlo jet model, with an initial impulse event in the shape of an open, thick-walled cone. As seen from Earth, the center of the plume is derived to be at a position angle of about 255 and about 20 this side of the plane of the sky, i.e., near the limb of the nucleus. Most of the observed ejecta material had an initial outflow velocity of less than 0.23 km s À1and particle sizes of less than 2.5 m (assuming compact grains). This resulted in the rapid development of a dust tail from ejecta particles as they are pushed away from the Sun by radiation pressure. Each daughter gas species exhibited an increase in production, with peaks occurring 1-2 days after impact, followed by a gradual decay back to baseline values; the shapes of these light curves suggest that the postimpact excess is due to the vaporization of ices within the ejecta over the course of a few days. In nearly all respects, comet Tempel 1 returned to preimpact conditions only 6 days after the event.

show abstract

The Deep Impact Earth-Based Campaign

Cited by 34 publications

References 24 publications

Mid-infrared spectra of comet nuclei

Mid-infrared spectra of comet nuclei

Deep Impact: A Large-Scale Active Experiment on a Cometary Nucleus

Photometry and Imaging Results for Comet 9P/Tempel 1 andDeep Impact: Gas Production Rates, Postimpact Light Curves, and Ejecta Plume Morphology

Contact Info

Product

Resources

About