Characterization of the Abydos region through OSIRIS high-resolution images in support of CIVA measurements

Alice Lucchetti (1, 2) , Gabriele Cremonese (2) , Laurent Jorda (3) , François Poulet (4) , Jean-Pierre Bibring (4) , Maurizio Pajola (1) , Fiorangela La Forgia (5) , Matteo Massironi (6) , Mohamed El-Maarry (7) , Nilda Oklay (8) , Holger Sierks (8) , Cesare Barbieri (5) , Philippe Lamy (3) , Rafael Rodrigo (9, 10) , Detlef Koschny (11) , Hans Rickman (12, 13) , Horst U. Keller (14) , Jessica Agarwal (7) , Michael F. A'Hearn (15) , Maria Antonietta Barucci (16) , Jean-Loup Bertaux (17) , Ivano Bertini (1) , Vania da Deppo (18) , Björn Davidsson (12) , Stefano Debei (19) , Mariolino de Cecco (20) , Sonia Fornasier (16) , Marco Fulle (21) , Olivier Groussin (3) , Pedro J. Gutiérrez (22) , Carsten Güttler (8) , Stubbe F. Hviid (23) , Wing-Huen Ip (24) , Jörg Knollenberg (23) , J.-Rainer Kramm (8) , Ekkehard Kührt (23) , Michael Küppers (25) , Luisa Lara (22) , Monica Lazzarin (5) , Jose Lopez-Moreno (22) , Francesco Marzari (5) , Stefano Mottola (23) , Giampiero Naletto (26, 1) , Frank Preusker (23) , Frank Scholten (23) , Nicolas Thomas (7) , Cécilia Tubiana (8) , Jean-Baptiste Vincent (8)

1 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
2 OAPD - INAF - Osservatorio Astronomico di Padova
3 LAM - Laboratoire d'Astrophysique de Marseille
4 IAS - Institut d'astrophysique spatiale
5 Dipartimento di Fisica e Astronomia "Galileo Galilei"
6 Dipartimento di Geoscienze [Padova]
7 Physikalisches Institut [Bern]
8 MPS - Max-Planck-Institut für Sonnensystemforschung
9 ISSI - International Space Science Institute [Bern]
10 CAB - Centro de Astrobiologia [Madrid]
11 RSSD - Research and Scientific Support Department, ESTEC
12 Department of Physics and Astronomy [Uppsala]
13 CBK - Space Research Centre of Polish Academy of Sciences
14 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
15 Department of Astronomy [College Park]
16 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
17 PLANETO - LATMOS
18 IFN - CNR Institute for Photonics and Nanotechnologies
19 Department of Industrial Engineering [Padova]
20 University of Trento [Trento]
21 OAT - INAF - Osservatorio Astronomico di Trieste
22 IAA - Instituto de Astrofísica de Andalucía
23 DLR Institut für Planetenforschung
24 IANCU - Institute of Astronomy [Taiwan]
25 Operations Department (ESAC)
26 DEI - Department of Information Engineering [Padova]

On 12 November 2014, the European mission Rosetta delivered the Philae lander on the nucleus of comet 67P/Churyumov-Gerasimenko (67P). After the first touchdown, the lander bounced three times before finally landing at a site named Abydos. Aims. We provide a morphologically detailed analysis of the Abydos landing site to support Philae’s measurements and to give context for the interpretation of the images coming from the Comet Infrared and Visible Analyser (CIVA) camera system onboard the lander. Methods. We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 6 December 2014 to perform the analysis of the Abydos landing site, which provided the geomorphological map, the gravitational slope map, the size-frequency distribution of the boulders. We also computed the albedo and spectral reddening maps. Results. The morphological analysis of the region could suggest that Philae is located on a primordial terrain. The Abydos site is surrounded by two layered and fractured outcrops and presents a 0.02 km2 talus deposit rich in boulders. The boulder size frequency distribution gives a cumulative power-law index of −4.0 + 0.3/ − 0.4, which is correlated with gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. The average value of the albedo is 5.8% at λ1= 480.7 nm and 7.4% at λ2= 649.2 nm, which is similar to the global albedos derived by OSIRIS and CIVA, respectively.

Keywords: 67P/Churyumov-Gerasimenko; comets; Data analysis

Domains: Earth and Planetary Astrophysics [astro-ph.EP]

Alice Lucchetti, Gabriele Cremonese, Laurent Jorda, François Poulet, Jean-Pierre Bibring, et al.. Characterization of the Abydos region through OSIRIS high-resolution images in support of CIVA measurements. Astronomy and Astrophysics - A&A, 2016, 585, L1 (5 p.). ⟨10.1051/0004-6361/201527330⟩. ⟨insu-01234274⟩