The problem of C_7^- as source of diffuse interstellar bands revisited

¹ Special Astrophysical Observatory, Nizhnij Arkhyz 369167, Russia e-mail: faig@sao.ru
² Center for Astronomy, Nicholas Copernicus University, Gagarina 11, 87-100 Toruń, Poland e-mail: nirski@astri.uni.torun.pl, jacek@astri.uni.torun.pl

Corresponding author: G. Galazutdinov gala@sao.ru

Received: 22 March 2001
Accepted: 8 August 2001

Abstract

We used spectra of several bright, reddened stars, most of them likely to be obscured by individual interstellar clouds, to examine the proposition that may carry several diffuse interstellar bands (DIBs) (Tulej et al. 1998). To search for the broad features of the B X system we used low resolution, very high spectra, but even in heavily reddened objects the predicted bands remain undetectable. High resolution () spectra prove that the diffuse bands, found in close vicinity of narrow lines belonging to the A X system, show variable strength ratios from object to object which proves that they are not of the same origin. The paper brings thus evidence that the molecule does not cause any of the detected DIBs.