Origin of the high N2/CO ratio in comet C/2016 R2 (PanSTARRS)
Abstract
Recent observations of the long period comet C/2016 R2 (PanSTARRS) indicate an unusually high N2/CO abundance ratio, typically larger than 0.05, and at least 10 times higher than the one measured in 67P/Churyumov-Gerasimenko. Because N2 is usually depleted in these bodies, the N2/CO ratio measured in C/2016 R2 (PanSTARRS) suggests that its formation conditions in the protosolar nebula differ from those of the other comets. Here we show that this abundance ratio can be explained by C/2016 R2 (PanSTARRS)'s agglomeration from CO-dominated clathrates and N2 pure condensate, provided that the water abundance was slightly supersolar ( 1.3 x (O/H2)protosolar) in the protosolar nebula and that the formation temperature of cometary grains decreased down to 22 K at least.
- Publication:
-
EPSC-DPS Joint Meeting 2019
- Pub Date:
- September 2019
- Bibcode:
- 2019EPSC...13.1136M