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Astron. Astrophys. 317, L59-L62 (1997)

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Letter to the Editor

New evidences for interstellar C60+*

B.H. Foing 1, 2 and P. Ehrenfreund 3, 2

1 Solar System Division, ESA Space Science Department, ESTEC/SO, 2200 AG Noordwijk, The Netherlands
2 Institut Astrophysique Spatiale, CNRS, Bat 121, Campus d'Orsay, France
3 Leiden Observatory, P.O. Box 9513, 2300 RA Leiden, The Netherlands

Received 22 October 1996 / Accepted 21 November 1996


The discovery and synthesis of fullerenes led to the hypothesis that they may be present and stable in interstellar space. As first evidence for the largest molecule ever detected in space, we have recently detected two new diffuse interstellar bands (DIBs) in the near-infrared that are consistent with laboratory measurements of the C60 cation. The inferred abundance (up to 0.9 % of cosmic carbon locked in C60 [FORMULA]) suggested that fullerenes may play an important role in interstellar chemistry. We present new observations towards HD183143, HD37022 and HD 80077 at 9600 Å from CFHT and ESO. The high quality of the spectra confirms without doubt the presence of the two DIBs at 9577 and 9632 Å and allows to measure reliably their strength, width and band ratio. The two correlated DIBs decrease in a UV shielded cold cloud (HD80077) but increase in a region dominated by extreme UV radiation (HD37022), with a band ratio constant within errors. Both DIBs show the same width, also consistent with a common carrier. This width of 3 cm-1 is compatible with rotational contours of C60 fullerene molecules. These results bring new evidences for C60 [FORMULA] in addition to the match with laboratory spectra.

Key words: ISM:molecules; ISM:dust; ISM:individual: HD183143, HD37022, HD80077; Line:profiles

* Based on observations with CFHT 3.6m and ESO CAT telescopes.

Send offprint requests to: B.H. Foing

© European Southern Observatory (ESO) 1997

Online publication: July 8, 1998