The EDIBLES survey

Context. Numerous studies of diffuse interstellar band (DIB) profiles have detected substructures, which in turn suggests that large molecules are acting as their carriers. However, some of the narrowest DIBs generally do not show such substructures, suggesting the possibility of very small carriers. Aims. Based on the previously found tight correlation of the three narrow DIBs at 6196, 6440, and 6623 Å and the present detection of weaker side DIBs to each of them in the extensive dataset from the ESO Diffuse Interstellar Bands Large Exploration Survey, we investigated whether they may stem from small linear carrier molecules. This approach can lead to concrete DIB carrier suggestions, which can be tested in laboratory measurements in future studies. Methods. We suggest that the DIBs we studied here represent individual rotational transitions of a small molecule. We determined the molecular constants from observations and compared them with data from a large set of quantum-chemical calculations to constrain possible carrier candidates. Furthermore, we determined the rotational temperatures by fitting line ratios using the fitted molecular models. Results. We determined molecular constants for three DIB systems and the corresponding transition types. The fitted rotational temperatures lie within the range of known interstellar diatomic molecules. We identified several DIB carrier candidates, almost all of them molecular ions. Some of them are metastable species, indicating the possibility of collision complexes as DIB carriers. Conclusions. If our hypothesis holds, this would be a major step towards the identification of a carrier molecule of the 6196 Å DIB, the strongest among the narrow DIBs.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-02-28
DOI
https://doi.org/10.1051/0004-6361/202453259
Citations
1
Primary Topic
Atmospheric Ozone and Climate
Type
article
Field-Weighted Citation Impact
1.30

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article

The EDIBLES survey

Milan Ončák, Bernard Foing, J. Cami, Jacco Th. van Loon et al.
1 citations
Astronomy and Astrophysics
Atmospheric Ozone and Climate
1.30
article

The EDIBLES survey

Milan Ončák, Bernard Foing, J. Cami, Jacco Th. van Loon, J. V. Smoker, A. Farhang, R. Lallement, A. Ebenbichler, Martin Cordiner, N. Przybilla, Helgi Rafn Hróðmarsson, P. Ehrenfreund, N. L. J. Cox, Charmi Bhatt
article en
1 citations

Abstract

Context. Numerous studies of diffuse interstellar band (DIB) profiles have detected substructures, which in turn suggests that large molecules are acting as their carriers. However, some of the narrowest DIBs generally do not show such substructures, suggesting the possibility of very small carriers. Aims. Based on the previously found tight correlation of the three narrow DIBs at 6196, 6440, and 6623 Å and the present detection of weaker side DIBs to each of them in the extensive dataset from the ESO Diffuse Interstellar Bands Large Exploration Survey, we investigated whether they may stem from small linear carrier molecules. This approach can lead to concrete DIB carrier suggestions, which can be tested in laboratory measurements in future studies. Methods. We suggest that the DIBs we studied here represent individual rotational transitions of a small molecule. We determined the molecular constants from observations and compared them with data from a large set of quantum-chemical calculations to constrain possible carrier candidates. Furthermore, we determined the rotational temperatures by fitting line ratios using the fitted molecular models. Results. We determined molecular constants for three DIB systems and the corresponding transition types. The fitted rotational temperatures lie within the range of known interstellar diatomic molecules. We identified several DIB carrier candidates, almost all of them molecular ions. Some of them are metastable species, indicating the possibility of collision complexes as DIB carriers. Conclusions. If our hypothesis holds, this would be a major step towards the identification of a carrier molecule of the 6196 Å DIB, the strongest among the narrow DIBs.

Astronomy and AstrophysicsVol. 695
Leiden University (NL), Western University (CA), Centre National de la Recherche Scientifique (FR), Goddard Space Flight Center (US), University of America (US), Délégation Paris 7 (FR), Universität Innsbruck (AT), Université Paris-Est Créteil (FR), Université Paris Cité (FR), Université Paris Sciences et Lettres (FR), Paris-Est Sup (FR), Sorbonne Paris Cité (FR), Galaxies, Etoiles, Physique et Instrumentation (FR), Royal Observatory (GB), Groupe de Recherche en Agriculture Biologique (FR), European Southern Observatory (CL), Laboratoire Interuniversitaire des Systèmes Atmosphériques (FR), Institute for Research in Fundamental Sciences (IR), Laboratoire Techniques, Territoires et Sociétés (FR), European Space Research and Technology Centre (NL), UK Astronomy Technology Centre (GB), Keele University (GB), Catholic University of America (US), Search for Extraterrestrial Intelligence (US)
Austrian Science Fund, Universität Innsbruck, Natural Sciences and Engineering Research Council of Canada
Openalex Percentile: Top 26%
Atmospheric Ozone and Climate
1.30
DOIOpen Access PDFOpenAlex
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