Gemini and Lowell Observations of 67P/Churyumov-Gerasimenko During the Rosetta Mission

Abstract

We present observations of comet 67P/Churyumov-Gerasimenko acquired in support of the $Rosetta$ mission. We obtained usable data on 68 nights from 2014 September until 2016 May, with data acquired regularly whenever the comet was observable. We collected an extensive set of near-IR $J$, $H$, and $Ks$ data throughout the apparition plus visible-light images in $g^{\prime }$, $r^{\prime }$, $i^{\prime }$, and $z^{\prime }$ when the comet was fainter. We also obtained broadband $R$ and narrowband $CN$ filter observations when the comet was brightest using telescopes at Lowell Observatory. The appearance was dominated by a central condensation and the tail until 2015 June. From 2015 August onwards there were clear asymmetries in the coma, which enhancements revealed to be due to the presence of up to three features (i.e., jets). The features were similar in all broadband filters; $CN$ images did not show these features but were instead broadly enhanced in the southeastern hemisphere. Modeling using the parameters from Vincent et al. (2013) replicated the dust morphology reasonably well, indicating that the pole orientation and locations of active areas have been relatively unchanged over at least the last three apparitions. The dust production, as measured by $A(0^{\circ })f\rho$ peaked $\sim$30 days after perihelion and was consistent with predictions from previous apparitions. $A(0^{\circ })f\rho$ as a function of heliocentric distance was well fit by a power-law with slope $-$4.2 from 35-120 days post-perihelion. We detected photometric evidence of apparent outbursts on 2015 August 22 and 2015 September 19, although neither was discernible morphologically in this dataset.

Accepted by MNRAS; 15 pages, 6 figures, 2 tables

References in corpus (7)

• A New Algorithm For Difference Image Analysis
• Summer fireworks on comet 67P
• Image Enhancement Techniques for Quantitative Investigations of Morphological Features in Cometary Comae: A Comparative Study
• The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission
• Mt. Wendelstein Imaging of the Post-Perihelion Dust Coma of 67P/Churyumov-Gerasimenko in 2015/2016
• 2014-2015 Multiple Outbursts of 15P/Finlay
• On the origin of inner coma structures observed by Rosetta during a diurnal rotation of comet 67P/Churyumov-Gerasimenko

Cited by in corpus (6)

• The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission
• Near-UV and optical spectroscopy of comets using the ISIS spectrograph on the WHT
• Analysis of Hybrid Gas-Dust Outbursts Observed at 67P/Churyumov-Gerasimenko
• Searching for Outbursts in the Ground-Based Photometry of 67P/Churyumov-Gerasimenko
• MUSE observations of comet 67P/Churyumov-Gerasimenko: A reference for future comet observations with MUSE
• VLT spectropolarimetry of comet 67P: Dust environment around the end of its intense Southern summer