Strong CO+ and N2+ Emission in Comet C/2016 R2 (Pan-STARRS)
Abstract
We report on imaging and spectroscopic observations of comet C/2016 R2 (Pan-STARRS) obtained with the 0.8 m and 2.7 m telescopes of McDonald Observatory in 2017 November and December, respectively. The comet was at a heliocentric distance greater than 3 au during both sets of observations. The images showed a well-developed tail with properties that suggested it was an ion tail. The spectra confirmed that we were observing well-developed bands of CO+ and N2+. The N2+ detection was unequivocally cometary and was one of the strongest bands of N2+ detected in a comet spectrum. We derived the ratio of these two ions and from that we were able to derive that N2/CO = 0.15. This is the highest such ratio reported for a comet.
This Letter includes data taken at The McDonald Observatory of The University of Texas at Austin.- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2018
- DOI:
- 10.3847/2041-8213/aaab57
- arXiv:
- arXiv:1801.01199
- Bibcode:
- 2018ApJ...854L..10C
- Keywords:
-
- comets: individual: 2016 R2;
- molecular processes;
- protoplanetary disks;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- Published in ApJL 9 February 2018. This version includes an erratum on the last page after references (accepted by ApJL) on the value of N2/CO