Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide

Abstract

A spectral survey in the 1 mm wavelength range was undertaken in the long-period comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy) using the 30 m telescope of the Ins titut de radioastronomie millimétrique (IRAM) in April and November−December 2013. We report the detection of ethylene glycol (CH 2 OH) 2 (aGg' conformer) and formamide (NH 2 CHO) in the two comets. The abundances relative to water of ethylene glycol and formamide are 0.2-0.3% and 0.02% in the two comets, similar to the values measured in comet C/1995 O1 (Hale-Bopp). We also report the detection of HCOOH and CH 3 CHO in comet C/2013 R1 (Lovejoy), and a search for other complex species (methyl formate, glycolaldehyde).

TRAPPIST photometry and imaging monitoring of comet C/2013 R1 (Lovejoy): Implications for the origin of daughter species

“…Our values agree within the error bars with the ones reported by Biver et al (2014) and Paganini et al (2014b) for early November. In October, however, the OH production rates we derived are slightly higher than the water production rates measured by Paganini et al (2014a).…”

“…In October, the CN and HCN production rates are consistent between each other (except for October 27 and 29 for which HCN production rates reported by Paganini et al 2014b are almost a factor two lower than those measured a few days before and a few days after, maybe because of rotational variation very close to the nucleus). In November, our CN production rates agree with those reported by Paganini et al (2014b) and Biver et al (2014), especially if we take the rise in comet activity into account. The HCN production rates reported by Agúndez et al (2014) are lower than our CN production rates, but they are also lower than those derived by Paganini et al (2014b) and Biver et al (2014) only a few days earlier.…”

“…In November, our CN production rates agree with those reported by Paganini et al (2014b) and Biver et al (2014), especially if we take the rise in comet activity into account. The HCN production rates reported by Agúndez et al (2014) are lower than our CN production rates, but they are also lower than those derived by Paganini et al (2014b) and Biver et al (2014) only a few days earlier.…”

“…Only a few results have been published so far about comet C/2013 R1 (Lovejoy). We summarize the results reported in Paganini et al (2014b), Agúndez et al (2014), andBiver et al (2014) in Table 4, along with our daughter species production rates. From this table, we notice that there is a significant dispersion between production rates measured almost simultaneously with different instruments and from different wavelength ranges.…”

The Main Belt Comets and ice in the Solar System

“…With large dishes or arrays on Earth a large number of molecules have been identified in comets (e.g., Biver et al 2002Biver et al , 2014, especially hydrocarbons, with methanol and HCN being most regularly observed, and abundances normally measured relative to HCN. Water is generally not identified from the ground, although Drahus et al (2012) were able to detect the 183 GHz band with the 30 m IRAM telescope during the close approach of comet 103P, at Q = 1.7 × 10 25 mol s −1 .…”