Authors

J. M. Bauer; E. Kramer; A. K. Mainzer; R. Stevenson; T. Grav; J. R. Masiero; R. G. Walker; Y. R. Fernandez; K. J. Meech; C. M. Lisse; P. R. Weissman; R. M. Cutri; J. W. Dailey; F. J. Masci; D. J. Tholen; G. Pearman; E. L. Wright;Wise Team

Comments

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Abbreviated Journal Title

Astrophys. J.

Keywords

comets: individual (67P); SPACE-TELESCOPE OBSERVATIONS; THERMAL-MODEL CALIBRATION; INFRARED-SURVEY-EXPLORER; NEAR-EARTH ASTEROIDS; COMET 103P/HARTLEY 2; DUST TRAIL; PHYSICAL-PROPERTIES; SOLAR-SYSTEM; 2P/ENCKE; Astronomy & Astrophysics

Abstract

On 2010 January 18-19 and June 28-29, the Wide-field Infrared Survey Explorer (WISE) spacecraft imaged the Rosetta mission target, comet 67P/Churyumov-Gerasimenko. We present a preliminary analysis of the images, which provide a characterization of the dust environment at heliocentric distances similar to those planned for the initial spacecraft encounter, but on the outbound leg of its orbit rather than the inbound. Broadband photometry yields low levels of CO2 production at a comet heliocentric distance of 3.32 AU and no detectable production at 4.18 AU. We find that at these heliocentric distances, large dust grains with mean grain diameters on the order of a millimeter or greater dominate the coma and evolve to populate the tail. This is further supported by broadband photometry centered on the nucleus, which yield an estimated differential dust particle size distribution with a power-law relation that is considerably shallower than average. We set a 3 sigma upper limit constraint on the albedo of the large-grain dust at < = 0.12. Our best estimate of the nucleus radius (1.82 +/- 0.20 km) and albedo (0.04 +/- 0.01) are in agreement with measurements previously reported in the literature.

Journal Title

Astrophysical Journal

Volume

758

Issue/Number

1

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

8

WOS Identifier

WOS:000309520500018

ISSN

0004-637X

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