EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign

K. J. Meech (1) , Michael F. A'Hearn (2) , J. A. Adams (3) , P. Bacci (4) , J. Bai (5) , L. Barrera (6) , M. Battelino (7) , J. M. Bauer (8) , E. Becklin (9) , B. Bhatt (10) , N. Biver (11) , D. Bockelée-Morvan (11) , Dennis Bodewits (2) , H. Böhnhardt (12) , J. Boissier , B. P. Bonev , W. Borghini , J. R. Brucato , E. Bryssinck , M. W. Buie , H. Canovas , D. Castellano , S. B. Charnley (13) , W. P. Chen , P. Chiang , Y.-J. Choi , D. J. Christian , Y.-L. Chuang , A. L. Cochran (14) , P. Colom (11) , M. R. Combi (15) , I. M. Coulson , J. Crovisier (11) , N. Dello Russo (16) , K. Dennerl , K. Dewahl , M. A. Disanti (13) , M. Facchini , T. L. Farnham (2) , Y. Fernández , H. G. Florén , U. Frisk (7) , T. Fujiyoshi , R. Furusho , T. Fuse , G. Galli , D. A. García-Hernández (17) , A. Gersch (2) , Z. Getu , E. L. Gibb , M. Gillon , E. Guido , R. A. Guillermo (1) , Edith Hadamcik (18) , O. Hainaut , H.B. Hammel , D.E. Harker , J.K. Harmon , W.M. Harris , P. Hartogh (12) , M. Hashimoto , B. Häusler , T. Herter (3) , A. Hjalmarson , S.T. Holland (13) , M. Honda , S. Hosseini , E.S. Howell , N. Howes , H. H. Hsieh (1) , H.-Y. Hsiao , D. Hutsemékers , S.M. Immler (13) , W.M. Jackson , S.V. Jeffers , E. Jehin , T.J. Jones , M. de Juan Ovelar , H. M. Kaluna (1) , T. Karlsson (7) , H. Kawakita , J. V. Keane (1) , L.D. Keller , M. S. Kelley (2) , D. Kinoshita , N.N. Kiselev , J. Kleyna (1) , M.M. Knight , H. Kobayashi , H.A. Kobulnicky , L. Kolokolova (2) , M. Kreiny , Y.-J. Kuan , M. Küppers , J.M. Lacruz , W.B. Landsman (13) , L.M. Lara , A. Lecacheux (11) , Anny Chantal Levasseur-Regourd (18) , B. Li , J. Licandro , R. Ligustri , Z.-Y. Lin , M. Lippi (12) , D.C. Lis , C. M. Lisse (16) , A.J. Lovell , S.C. Lowry , H. Lu , S. Lundin (7) , K. Magee-Sauer , P. Magain , J. Manfroid , E. Mazzotta Epifani , A. Mckay , M.D. Melita , H. Mikuz , S.N. Milam (13) , G. Milani , M. Min , R. Moreno , B.E.A. Mueller , M.J. Mumma (13) , M. Nicolini , M.C. Nolan , H.L. Nordh , P.B. Nowajewski , Odin Team , T. Ootsubo , L. Paganini (13) , C. Perrella , J. Pittichová (1) , E. Prosperi , Y.L. Radeva (13) , W. T. Reach (9) , A.J. Remijan , M. Rengel (12) , T.E. Riesen (1) , M. Rodenhuis , D.P. Rodríguez , R.W. Russell , D. K. Sahu (10) , N.H. Samarasinha , A. Sánchez Caso , A. Sandqvist , G. Sarid (1) , M. Sato , D.G. Schleicher , E.W. Schwieterman , A.K. Sen , D. Shenoy , J.-C. Shi , Y. Shinnaka , J. Skvarc , C. Snodgrass (12) , M.L. Sitko , S. Sonnett (1) , S. Sosseini , G. Sostero , S. Sugita , B.M. Swinyard , S. Szutowicz , N. Takato , P. Tanga (19) , P.A. Taylor , G.-P. Tozzi , R. Trabatti , J. M. Trigo-Rodríguez (17) , C. Tubiana (12) , M. de Val-Borro (12) , W. Vacca (9) , B. Vandenbussche , J. Vaubaillion (20) , F.P. Velichko , S.F. Velichko , R. J. Vervack (16) , M.J. Vidal-Nunez , G.L. Villanueva (13) , C. Vinante , J.-B. Vincent (12) , M. Wang , L.H. Wasserman , J. Watanabe , H. A. Weaver (16) , P.R. Weissman , S. Wolk , D.H. Wooden , C.E. Woodward , M. Yamaguchi , T. Yamashita , P.A. Yanamandra-Fischer , Bin Yang (1) , J.-S. Yao , D.K. Yeomans , T. Zenn (1) , H. Zhao , J.E. Ziffer

1 Institute for Astronomy [Honolulu]
2 Department of Astronomy [College Park]
3 Department of Astronomy [Ithaca]
4 Centro Astronomico di Libbiano
5 Yunnan Astronomical Observatory
6 UMCE - Universidad Metropolitana de Ciencias de la Educación
7 SSC - Swedish Space Corporation
8 JPL - Jet Propulsion Laboratory
9 Stratospheric Observatory for Infrared Astronomy
10 IIA - Indian Institute of Astrophysics
11 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
12 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
13 GSFC - NASA Goddard Space Flight Center
14 McDonald Observatory
15 AOSS - Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor]
16 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
17 ICE-CSIC - Institut de Ciencies de l'Espai [Barcelona]
18 PLANETO - LATMOS
19 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides
20 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

K. J. Meech, Michael F. A'Hearn, J. A. Adams, P. Bacci, J. Bai, et al.. EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign. The Astrophysical journal letters, 2011, 734 (1), pp.L1. ⟨10.1088/2041-8205/734/1/L1⟩. ⟨hal-00595472⟩