Optical observations of comet 67P/Churyumov-Gerasimenko with the Nordic Optical Telescope: Comet activity before the solar conjunction

• Published in: Astronomy and astrophysics (Berlin) 2015-11, Vol.583, p.A10
• Main Authors: Zaprudin, B, Lehto, H J, Nilsson, K, Pursimo, T, Somero, A, Snodgrass, C, Schulz, R
• Format: Article
• Language: English
• Subjects: Calibration; Color; Comets; European Space Agency; Monitoring; Photometry; Rosetta mission; Space telescopes
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201525703

67P/Churyumov-Gerasimenko (67P) is a short-period Jupiter-family comet that was chosen as a target for the Rosetta mission by the European Space Agency (ESA). Monitoring of 67P with the Nordic Optical Telescope (NOT; La Palma, Spain) intends to aid this mission by providing ground-based reference information about the overall activity of the target and its astrometric position before the rendezvous. The aim of this work is to perform the photometric and the astrometric monitoring of comet 67P with the NOT and to compare the results with the latest predictions for its position and activity. The very first observations were performed in the V band alone, but in the latest observations, the R band was used as well to estimate the color and nature of activity of the target. Photometric magnitudes in two colors were monitored during the period of observations. The astrometric calibration results we obtained were consistent with the predictions of the ephemerides of the Minor Planet Center, but at the moment these results are superseded with the more precise astrometric data from the Rosetta spacecraft.