A Rigorous Attempt to Verify Interstellar Glycine

By Lewis E. Snyder, F. Lovas, J. Hollis, D. Friedel, P. Jewell, A. Remijan, V. Ilyushin, E. Alekseev, S. Dyubko. 2004

292 citations recorded by the source corpus.

In 2003, Kuan and coworkers reported the detection of interstellar glycine (NH2CH2COOH) based on observations of 27 lines in 19 different spectral bands in one or more of the sources Sgr B2(N-LMH), Orion KL, and W51 e1/e2. They supported their detection report with rotational temperature diagrams for all three sources. In this paper we present essential criteria that can be used in a straightforward analysis technique to confirm the identity of an interstellar asymmetric rotor such as glycine. We use new laboratory measurements of glycine as a basis for applying this analysis technique, both to our previously unpublished 12 m telescope data and to the previously published Swedish-ESO Submillimetre Telescope (SEST) data of Nummelin and colleagues. We conclude that key lines necessary for an interstellar glycine identification have not yet been found. We identify some common molecular candidates that should be examined further as more likely carriers of several of the lines reported as glycine. Finally, we illustrate that a rotational temperature diagram used without the support of correct spectroscopic assignments is not a reliable tool for the identification of interstellar molecules.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/5c89c67eb8e772af07574e60c1448f9ddd1824c0

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. R. Garrod
2. B. McGuire
3. E. Herbst
4. K. Menten
5. Arnaud Belloche
6. H. S. P. Müller
7. H. Linnartz
8. H. Cuppen

In Instrumentation

1. Astronomy
2. U. Virginia
3. Japan.
4. UK.
5. Usa
6. B. McGuire
7. K. Menten
8. Y. Aikawa

Citations in the corpus

• Increased complexity in interstellar chemistry: detection and chemical modeling of ethyl formate and n-propyl cyanide in Sagittarius B2(N) (2009, methodology): “We used equation A5 of Snyder et al. (2005) to compute the ordinate values: ln ( Nu gu ) = ln ( 1.67WT × 1014 S µ2Bν ) = − Eu Trot + ln (NT Z ) , (1) whereWT is the integrated intensity in K km s−1 in main-beam brightness temperature scale,S µ2 the line strength times the 16 156,10 – 146,9…”
• A THREE-PHASE CHEMICAL MODEL OF HOT CORES: THE FORMATION OF GLYCINE (2013, background): “The search for the simplest amino acid, glycine (NH2C 2COOH), toward interstellar sources has not so far yielded a detection (Snyder et al. 2005); recent upper limits toward Sgr B2(N), a spectrally- and chemically-rich hot-core source in the Galactic Center, are around 1014 – 1015 cm−2 for…”
• Complex organic molecules in protoplanetary disks (2013, background): “…of the ‘holy grails’ of prebiotic chemistry; however, thus far, searches for gas-phase glycine towards hot cores have been unsuccessful (see, e.g., Snyder et al. 2005) In Walsh et al. (2010) and Walsh et al. (2012), henceforth referred to as WMN10 and WNMA12, we calculated the chemical…”
• Mechanisms of Amino Acid Formation in Interstellar Ice Analogs (2007, background): “Although a tentative identifi­ cation of interstellar glycine has been reported, this identifica­ tion has yet to be verified (Kuan et al. 2003; Snyder et al. 2005).”
• Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M) (2013, background): “The reliability of a new detection is significantly improved by checking the presence of a molecule as a whole instead of relying on only detecting a few specific transitions (see, e.g., Snyder et al. 2005 for the disputed case of interstellar glycine).”
• Erratum: Detection of amino acetonitrile in Sgr B2(N) (2008, methodology): “Its recent “detection” claimed by Kuan et al. (2003) has been persuasively rebutted by Snyder et al. (2005).”
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules (2018, methodology): “The detection was later disputed by Snyder et al. (2005), who claimed to have identified a number of issues with the analysis.”
• Cometary glycine detected in samples returned by Stardust (2009, background): “However, this detection remains controversial because of limitations in assignment of spectral lines (Snyder et al. 2005).”
• Experimental evidence for glycolaldehyde and ethylene glycol formation by surface hydrogenation of CO molecules under dense molecular cloud conditions (2015, background): “Despite theoretical studies and laboratory-based work that show that glycine as well as several other amino acids should form in space (Muñoz Caro et al. 2002; Blagojevic, Petrie & Bohme 2003; Congiu et al. 2012; Garrod 2013), unambiguous detections are still lacking (Snyder et al. 2005).”