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

[Richard Miles]

Thanks Jeremy,

Nicolas Biver and his colleagues are making very valuable contributions with 
the IRAM 30m radio telescope studying neutral molecules escaping from 
cometary nuclei in the few hours before they finally get ionised and 
dissociate through exposure to solar radiation.

What is rather nice is that if you look in the current June issue of the 
Journal (now published), on page 149 there is a detailed drawing of Saturn 
(in Richard McKim's report of the 1994-95 apparition of that planet) exacted 
by the selfsame Nicolas Biver using the 1m Cass at Meudon, near Paris in 
1995. He is a great example of a professional astronomer who is also an 
amateur at heart, as he continues to report detailed visual observations of 
comets and other celestial objects with great skill as an observer.

On the composition of comets, we now know that there is quite a mixture of 
water-soluble compounds present with methanol being the most abundant 
species but there is also a fair amount of formaldehyde and then significant 
quantities of formic acid, ethylene glycol (standard antifreeze!), 
formamide, ammonia, etc. and then there will be lots of ionic salts present 
which cannot volatilise and so are never measured by remote observation. All 
of these hydrophilic compounds can act as a super antifreeze so that 
nyctogenic processes on the nighttime side of the nucleus can generate 
reservoirs of highly concentrated water-based mixtures metres below the 
surface that exist in liquid form at very low temperatures (< -100 degC) - 
that's when the fun begins!  Good luck Rosetta - if Philae lands 
successfully on Comet 67P then we are in for a Pandora's box of delights 
with the new discoveries to be made.

Richard Miles



----- Original Message ----- 
From: "Jeremy Shears" <bunburyobservatory at hotmail.com>
To: <comets-disc at britastro.org>
Sent: Tuesday, May 27, 2014 5:50 PM
Subject: [BAA Comets] Complex organic molecules in comets C/2012 F6 (Lemmon) 
and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide


....is the title of an A&Ap Lett. pre-print on today's arXiv posting. 
Includes ethylene glycol (antifreeze). Maybe of relevance to Richard's 
cryo-volcanism?
http://arxiv.org/abs/1405.6605
Go well!Jeremy
Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 
(Lovejoy): detection of ethylene glycol and formamide
N. Biver, D. Bockelée-Morvan, V. Debout, J. Crovisier, J. Boissier, D.C. 
Lis, N. Dello Russo, R. Moreno, P. Colom, G. Paubert, R. Vervack, H.A. 
Weaver(Submitted on 26 May 2014)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 Institut de radioastronomie 
millim\'etrique (IRAM) in April and November-December 2013. We report the 
detection of ethylene glycol (CH2OH)2 (aGg' conformer) and formamide 
(NH2CHO) 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 CH3CHO in comet C/2013 R1 (Lovejoy), and a search for 
other complex species (methyl formate, glycolaldehyde).