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Colors of comet 67P/Churyumov-Gerasimenko’s active pits and their surroundings as seen by OSIRIS on board Rosetta

Oklay, Nilda and Vincent, Jean-Baptiste and Besse, Sebastien and Fornasier, Sonia and Barucci, Maria Antonietta and Lara, Luisa and Scholten, Frank and Preusker, Frank and La Forgia, Fiorangela and Lazzarin, Monica and Sierks, Holger and Hall, Ian and OSIRIS, Team (2015) Colors of comet 67P/Churyumov-Gerasimenko’s active pits and their surroundings as seen by OSIRIS on board Rosetta. EGU General Assembly, 12-17 Apr 2015, Vienna, Austria.

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Official URL: http://meetingorganizer.copernicus.org/EGU2015/EGU2015-11341.pdf

Abstract

The OSIRIS scientific imager (Optical, Spectroscopic, and Infrared Remote Imaging System, Keller et al. 2007) on board ESA’s spacecraft Rosetta is an instrument designed to observe the comet nucleus with high spatial resolution, down to a few centimeters per pixel, to provide color information of the surface using its narrow angle camera (NAC) thanks to set of dedicated filters. OSIRIS is successfully observing comet 67P in the spectral range of about 250-1000 nm since Rosetta’s arrival to the comet in the summer 2014. The illuminated northern hemisphere of the comet nucleus was mapped with various spatial resolutions (down to 15 cm/px in some regions). Besides the determination of the surface morphology in great details, such high resolution images provided us a mean to unambiguously link some activity in the coma to a series of pits on the nucleus surface (Vincent et al. 2014). This work focuses on color variations inside and in the vicinity of these active pits. Using filter ratios to limit the effect of topography and illumination conditions, we found that the floor and walls of the pits exhibit the same less red slope of the active Hapi region. We measured a ratio of reflectance (IR)/reflectance (Blue) = 1.8 in the active area and pits while it is 2.1 elsewhere on the nucleus. A full understanding of the compositional implications will require a dedicated investigation, but our preliminary results indicate already that this spectral variation is characteristic of currently active regions on 67P. Indeed, on a large scale, comet 67P’s global spectrum shows a red slope also known from the ground based observations, slightly less red in the most active area (Hapi region) when compared to the average comet surface. Variegation is also found in other places showing activity such as the active pits mentioned above. The analysis is now extended to the photometrically corrected data set in order to be able to compare observations taken under different illumination conditions. The relevant images acquired between August and December 2014 are reduced using the standard OSIRIS calibration pipeline and then converted to reflectance values (I/F). Analyzed multispectral data is produced by using USGS ISIS3 software. This process includes the sub-pixel image registration, and photometric corrections.

Item URL in elib:https://elib.dlr.de/101343/
Document Type:Conference or Workshop Item (Poster)
Title:Colors of comet 67P/Churyumov-Gerasimenko’s active pits and their surroundings as seen by OSIRIS on board Rosetta
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Oklay, NildaMax-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077, Göttingen, GermanyUNSPECIFIED
Vincent, Jean-BaptisteMPI für SonnensystemforschungUNSPECIFIED
Besse, SebastienScientific Support Office, European Space Agency, 2201, Noordwijk, Netherlands.UNSPECIFIED
Fornasier, SoniaObservatoire de Paris-Meudon, FranceUNSPECIFIED
Barucci, Maria AntoniettaLESIA-Observatoire de Paris, FranceUNSPECIFIED
Lara, LuisaIAA-CSIC Granada, SpainUNSPECIFIED
Scholten, Frankfrank.scholten (at) dlr.deUNSPECIFIED
Preusker, Frankfrank.preusker (at) dlr.deUNSPECIFIED
La Forgia, FiorangelaUniversity of Padova, Department of Physics and Astronomy, Vicolo dell'Osservatorio 3, 35122 Padova, ItalyUNSPECIFIED
Lazzarin, MonicaUniversity of Padova, Department of Physics and Astronomy, Vicolo dell'Osservatorio 3, 35122 Padova, ItalyUNSPECIFIED
Sierks, HolgerMax-Planck-Institut für SonnensystemforschungUNSPECIFIED
Hall, IanMax Planck Institute for Solar System Research , Katlenburg-Lindau, GermanyUNSPECIFIED
OSIRIS, TeamUNSPECIFIEDUNSPECIFIED
Date:2015
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Rosetta, 67P, Color
Event Title:EGU General Assembly
Event Location:Vienna, Austria
Event Type:international Conference
Event Dates:12-17 Apr 2015
Organizer:European Geosciences Union
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt ROSETTA Instrumente
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geodesy
Deposited By: Scholten, Dipl.-Ing. Frank
Deposited On:05 Jan 2016 12:52
Last Modified:31 Jul 2019 19:58

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